Bio 202

Front 1

What is heredity

Back 1

the transmission of traits from one generation to the next

Front 2

what is genetics

Back 2

the scientific study of heredity and variation

Front 3

what are the 2 methods of reproduction and explain

Back 3

asexual- mitosis gives rise to 2 identical daughter cells
sexual- 2 parents contribute DNA to one offspring. The sperm & egg fuse during fertilization to give rise to a single cell that will develop into offspring

Front 4

what is a life cycle

Back 4

the genration to generation sequence of stages in the reproductive history of an organism

Front 5

what forms the basis of variations we see in organisms?

Back 5

homologous chromosomes

Front 6

What are alleles?

Back 6

alternative forms of a gene

Front 7

how how sex chromosomes distinguished from other chromosomes

Back 7

by being non homologus (females have XX & males have XY)

Front 8

what is a human somatic cell

Back 8

any cell other than gamete

Front 9

what is karyotype

Back 9

an ordered display of pairs of chromosomes from a cell

Front 10

what are the steps of meiosis

Back 10

interphase I of meiosis (chromosome replicate), meiosis I (homologus chromosomes seperate), meiosis II (sister chromatides seperate)

Front 11

what happens during prophase I

Back 11

homologus chromosomes become closely associated in synapsis, exchange segments via crossing over, and then seperate.

Front 12

what happens in synapsis

Back 12

homologus chromosomes loosely pair up, aligned gene by gene

Front 13

what indicates that crossing over had occured?

Back 13

presence of chiasma

Front 14

what happens in metaphase I

Back 14

paired homologus chromosomes line up at the metaphase plate, with one chromosome "facing" each pole. Then kinetochore microtubules attach to one of the 2 homologus chrsomosome, so that one homologue will be drawn to one pole, and the other homologue to the other pole.

Front 15

what happens in anaphase I

Back 15

pairs of homologus chromosomes seperate

Front 16

what does the chiasmata do

Back 16

hold homologues together

Front 17

what happens during telophase I and cytokinesis

Back 17

2 haploid daughter cells form

Front 18

what happens during prophase II

Back 18

a new spindle apparatus forms in each cell, and the nuclear membrane breaks down

Front 19

what happens in metaphase II

Back 19

chromosomes align along the metaphase plate in each cell and kinetochore microtubules from opposite poles attach to opposite sides of the same centromere

Front 20

what happens in telophase II

Back 20

the nuclear membranes re-form around 4 different clusters of chromosomes, and the chromosomes begin decondensing

Front 21

What does cytokinesis do

Back 21

seperates the cytoplasn and 4 haploid cells result

Front 22

what are the steps in mitosis

Back 22

prophase (chrmosome replicate), metaphase & telophase(chromosomes align at the metaphase plate), sister chromatids seperate during anaphase

Front 23

compare mitosis and meiosis

Back 23

1- mitosis conserves the # of chromosome sets, producing cells that are genetically identical to the parent cell
2-meiosis reduces the # of chromosome sets from 2 (diploid) to one (haploid), producing cells that differ genetically from eachother and from the parent cell
3- the mechanism for seperating sister chromatids is virtually identical in meiosis II and mitosis

Front 24

what are 3 events unique in meiosis?

Back 24

1-synapsis and crossing over in prophase I
2-at the metaphase plate, there are paired homologus chromosomes , instead of sister chromatids, that seperate and are carried to opposite poles of the cell

Front 25

whats the original source of genetic diversity?

Back 25

mutations (change in an organism's DNA)

Front 26

what is parthenogenesis

Back 26

development of an adult unfertilized egg which undergoes a mitotic division without cell cleavage to become a diploid cell

Front 27

what 3 mechanisms contribute to genetic variation?

Back 27

1-independant assortment of chromosomes
2-crossing over
3-random fertilization

Front 28

what is the # of combinations possible when chromosomes assort independantly into gametes?

Back 28

2^n where n is the haploid #

Front 29

what is independant assortment

Back 29

the results of alternative arrangements of maternal & paternal homologus chromosome pairs on the metaphase plate in meiosis I

Front 30

what happens during crossing over?

Back 30

homologus chromosomes pair up gene by gene and homologus portions of 2 nonsister chromatids trade places

Front 31

what is random fertilization

Back 31

the matter of chance of which 2 gametes fuse to form a zygote

Front 32

what is synapotnemal complex

Back 32

mechanism 4 double DNA strand damage repair

Front 33

what does gene disorder refer to

Back 33

the harmful effect a detrimental allele produces when it occurs at a significant frequency in a population

Front 34

what are most human genetic disorders caused by

Back 34

a mutated DNA sequence which encodes an altered protein

Front 35

what is a pedigree

Back 35

a family tree that describes the interrelationships of parents and children across generations.

Front 36

what do the dominance/recessiveness relationships of alleles depend on?

Back 36

the level at which we examine the phenotype

Front 37

What is Tay-Sachs disease?

Back 37

a dysfunctional enzyme causes an accumulation of lipids in the brain

Front 38

For Tay-Sachs disease, what are the dominance/recessiveness relationships of alleles?

Back 38

organismal level- the allele is recessive
biochemical level-the phenotype if incompletely dominant
molecular level- the alleles are codominant

Front 39

What causes cystic fibrosis

Back 39

mutation in the CFTR gene, which encodes a PM chloride channel protein. the mutation encodes a protein that is not efficiently delivered to the plasma membrane

Front 40

what does the loss of CFTR at PM do?

Back 40

it impairs the ability of cells to transport chloride ions into and out of the cell. Released Cl= causes the cells to release water (osmosis) and the water things the mucus. Without Cl- transport, there is less water, and the music thick and syrupy.

Front 41

what is sickle cell disease caused by?

Back 41

the substitution of a single amino acid in the hemoglobin protein in red blood cells.

Front 42

What kind of disorder is sickle cell anemia?

Back 42

a recessive inherited disorder in which afflicted individuals have defective hemoglobin, and thus are unable to properly transport oxygen to tissues.

Front 43

what are the symptoms of sickle cell anemia

Back 43

-physical weakness
-organ damage
-paralysis

Front 44

is the allele dominant or recessive for sickle cell disease

Back 44

organismal level- nonsickle allele is incompletely dominant to the sickle cell allele.
molecular level- the 2 alleles are codominant as both normal and abnormal (sick cell) hemoglobins are synthesized

Front 45

What are the characteristics of sickle cells

Back 45

-breakdown of red blood cells
-clumping of cells and clogging of small blood vessels
-accumulation of sickled cells in spleen

Front 46

homozygous (sickle cell) wild types are susceptible to what?

Back 46

malaria

Front 47

if a phenotype is due to autosomal dominant allele, individuals who are homozygous or heterozygous for the trait will display which phenotype?

Back 47

the dominant phenotype

Front 48

What is an example of a late onset lethal dominant disorder?

Back 48

Huntington's disease

Front 49

What is Huntington's disease and what is it caused by?

Back 49

it is a degenerative disease of the nervous system. its caused by defects in the huntington protein that leads to its gradual aggregation in the brain

Front 50

whats the mutation in huntington's disease and why is it dominant?

Back 50

trinucleotide repeat expansion disorder like Fragile-X syndrome which is a constriction at the tip of the X chromosome

Front 51

what is the phenomenon known as anticipation?

Back 51

when individuals are phenotypically normal, but their sons were affected, and later generations showed earlier onset and more severe symptoms.

Front 52

what is the normal function of protein made by FMRI

Back 52

to bind to mRNAs involved in neuron function and regulate translation

Front 53

What happens if the FMRI protein is not made?

Back 53

these mRNAs are not translated in sufficient amounts, the nerve cells die;loss of nerve cells can result in MR

Front 54

What is Fragile X syndrome caused by

Back 54

an expansion of CGG repeat

Front 55

what repeat if Huntington's disease caused by

Back 55

CAG repeat

Front 56

What is Friedrich's ataxia caused by

Back 56

GAA repeat

Front 57

What is myotonic dystrophy caused by

Back 57

CTG repeat

Front 58

what happens when the polyglutamine tract expands

Back 58

the protein must be folded correctly for its normal function but if the polyglutamine tract is expanded, the folding of this protein will not be normal

Front 59

if a trait appears equally often in males and females, what is it likely to be?

Back 59

autosomal

Front 60

if males are much more likely to have the trait, what is it likely to be?

Back 60

X-linked

Front 61

An affected male produces

Back 61

-carrier daughters
-normal sons

Front 62

A carrier female produces

Back 62

-carrier and normal daughters
-affected and normal sons

Front 63

what is nondisjunction?

Back 63

when the X chromosomes dont seperate

Front 64

what is trisomy

Back 64

3 chromosomes

Front 65

what is monosomy

Back 65

1 chromosome

Front 66

non disjunction of sex chromosomes can result in:

Back 66

-XXX triple-X females
-XXY males (Klinefelter syndrome)
-XO females (Turner syndrome)
-OY nonviable zygotes
-XYY males (Jacob syndrome)

Front 67

what does deletion do

Back 67

removes a chrmosomal segment

Front 68

what does duplication do

Back 68

repeats a segment

Front 69

what does inversion do

Back 69

reverses a segment within a chromosome

Front 70

what does translocation do

Back 70

moves a segment from one chromosome to another, nonhomologus one.

Front 71

what is genomic imprinting

Back 71

the phenotype depends on which parent passed along the alleles for those traits & it involves the silencing of certain genes that are "stamped" with an imprint during gamete production

Front 72

Whats an example of genomic imprinting?

Back 72

the mutant Igf2 allele inherited from the mother results in the mutant Igf2 not being expressed but the mutant Igf2 allele inherited from the father results in the normal Igf2 allele not being expressed

Front 73

what are extranuclear genes (or cytoplasmic genes)

Back 73

genes found in organelles in the cytoplasm, such as mitochondria and chloroplasts. theyre inherited maternally

Front 74

what do mutations in mitochondrial DNA do

Back 74

disrupt the mitochondria's ability to efficiently generate energy for the cell.

Front 75

What are frequently observed features of mutations in mitochondrial DNA

Back 75

-muscle weakness
-problems with movement
-diabetes
-loss of intellectual functions (dementia)
-hearing loss
-abnormalities involving the eyes and vision

Front 76

mutations in four mitochondrial genes have been identified in people with what disease?

Back 76

Leber hereditary optic neuropathy

Front 77

what are multifactorial disorders

Back 77

disorders with a genetic component plus environmental influence

Front 78

What necessitated cellular specialization and cellular signaling?

Back 78

the evolution of multicellular organisms

Front 79

what is cell communication necessary for?

Back 79

structural and functional integrity of tissues and organs

Front 80

what is signal transduction

Back 80

the process by which a cell converts an extracellular signal into a response

Front 81

what is a hormone

Back 81

an information-carrying molecule that is secreted from a cell, circulates in the body, and acts on target cells far from the signaling cell

Front 82

how do polypeptides serve as hormones

Back 82

theyre not lipid soluble; bind to receptors on surface of target cell

Front 83

how do amino acid derivatives serve as hormones

Back 83

most are not lipid soluble; bind to receptors on surface of target cell

Front 84

how do steroids serve as hormones?

Back 84

theyre lipid soluble; bind to receptors inside target cell

Front 85

what is the overview of cell signaling?

Back 85

1-reception (extracellular signal molecule binds to a receptor protein)
2-transduction (activation of an intercellular signaling pathway that is mediated by a series of signaling proteins)
3-response (one or more of these proteins interacts with a target protein)

Front 86

what is transduction

Back 86

when cascades of molecular interactions relay signals from receptors to target molecules in the cell

Front 87

whats good about multistep pathways?

Back 87

-can amplify a signal: a few molecules can produce a large cellular response
-provide more opportunities for coordination and regulation

Front 88

what is phosphorylation of proteins

Back 88

a major mechanism for regulating the activity of proteins, moving from an inactive to an active state.

Front 89

what is a ligand

Back 89

the signal molecule which fits into the receptor in a way thats similar to the interaction between a substrate and the catalytic site of an enzyme

Front 90

what are the 3 main types of membrane receptors?

Back 90

-G-protein-linked receptors
-receptor tyrosine kinases
-ion channel receptors

Front 91

what are G proteins

Back 91

peripheral membrane proteins located inside the cell that are closely associated with transmembrane signal receptors

Front 92

when are G proteins activated

Back 92

when they bind GTP

Front 93

when are G proteins deactivated

Back 93

when they hydrolyze the bound GTP and GDP

Front 94

what do tyrosine-kinase receptors do

Back 94

they mediate growth factors and local regulators that stimulate cells to grow and reproduce

Front 95

what is a distinguished feature of the tyrosine-kinase receptor

Back 95

it can activate many signal transduction pathways simultaneously, in contrast to the G protein receptor, which only activated a single pathway at a time

Front 96

what are ion-channel receptors

Back 96

oftern referred to as ligand-gated ion channel. when a signal molecule binds as a ligand to the receptor, the gate allows specific ions, such as Na+ or Ca+ through a channel in the receptor

Front 97

What did it show when the activation of glycogen phosphorylase by epinephrine could not happen with purified components in a test tube

Back 97

-epinephrine does not activate glycogen phosphorylase directly
-the plasma membrane is somehow involved

Front 98

what are second messengers

Back 98

small, non-protein, water-soluble molecules or ions that can readily spread throughout cells by diffusion

Front 99

what is the most common second messenger

Back 99

cyclic AMP (cAMP) and Ca++

Front 100

how does cAMP work?

Back 100

adenylyl cyclase, an enzyme in the plasma membrane, converts ATP to cAMP in response to an extracellular signal, phophodiesterase converts cAMP to AMP, quenching the signal.

Front 101

what did Sutherland show about cAMP

Back 101

that when epinephrine is bound to plasma membrane, cAMP is elevated and then glycogen is broken down to glucose

Front 102

what happens with epinephrine is bound to its receptor site?

Back 102

adenylyl cyclase is activated

Front 103

what is PlP2

Back 103

a membrane phospholipid thats cleaved by phospholipase C into inositol triphosphate (IP3) and diacylglycerol (DAG)

Front 104

what are relay molecules

Back 104

molecules that relay the signal from the receptor to the response

Front 105

what do phosphatase enzymes do

Back 105

remove the phosphates

Front 106

what does cell signaling lead to

Back 106

regulation of cytoplasmic activities or transcription

Front 107

what is apoptosis

Back 107

programmed or controlled cell suicide; a cell is chopped and packaged into vesicles that are digested by scavenger cells

Front 108

what are caspases

Back 108

main proteases (enzymes that cut up proteins) that carry out apoptosis

Front 109

what can apoptosis be triggered by

Back 109

-an extracellular death-signaling ligand
-DNA damage in the nucleus
-protein misfolding in the endoplasmic reticulum

Front 110

what is a virus

Back 110

a genome enclosed in a protective coat; viruses are infectious particles consisting of nucleic acid encases in a protein coat, and in some cases, a membranous envelope.

Front 111

what is an isolated virus

Back 111

a merely packaged set of genes going from one host to another.

Front 112

how do viruses reproduce

Back 112

using lytic or lysogenic cycles

Front 113

what is the lytic cycle

Back 113

a phage reproductive cycle that culminates in the death of the host cell. It also produces new phages and digests the host's cell wall, releasing the progeny viruses.

Front 114

what is a virulent phage

Back 114

a phage that reproduces only by the lytic cycle

Front 115

what does late gene expression generate

Back 115

capsid proteins and lytic enzymes

Front 116

what is the lysogenic cycle

Back 116

it replicates the phage genome without destroying the host. The viral DNA molecule is incorporated into the host cell's chromosome.

Front 117

what is the integrated viral DNA known as

Back 117

prophage (provirus)

Front 118

what are temperate phages

Back 118

phages that use both the lytic and lysogenic cycles

Front 119

what are the 2 key variables on the basic scheme of viral infection and reproductions that are represented among animal viruses

Back 119

1-the type of nucleic acid that serves as virus genetic material
2-the presence of absence of a membranous envelope

Front 120

what is a viral genome usually

Back 120

a single linear or circular molecule of nucleic acid

Front 121

what is a capsid

Back 121

a protein coat which encases a genome

Front 122

what are viral envelopes

Back 122

membranes cloaking their capsids; they're derived from the membrane of the host cell but also have some viral proteins and glycoproteins embedded within

Front 123

what is a host range

Back 123

the limited range of host cells which each type of virus can infect

Front 124

how do viruses identify host cells

Back 124

by a "lock and key" fit between proteins on the outside of virus and specific receptor molecules on the host's surface.

Front 125

where is the broadcast variety of RNA genomes found

Back 125

in viruses that infect animals

Front 126

The genome is a template for what?

Back 126

mRNA synthesis

Front 127

The mRNA is a template for what?

Back 127

viral genome replication

Front 128

what are retroviruses

Back 128

they're enveloped viruses possessing an RNA genome, and replicate via a DNA intermediate

Front 129

what's an example of a retrovirus

Back 129

Human immunodeficiency virus (HIV), the virus that causes AIDS

Front 130

how may viruses damage or kills cells

Back 130

by causing the release of hydrolytic enzymes from lysosomes

Front 131

what are vaccines

Back 131

harmless variants or derivatives of pathogenic microbes, that stimulate the immune system to mount defenses against the actual pathogen

Front 132

what is AZT (azido thymidine)

Back 132

a pyrimidine analogue used as an anti-HIV because it interferes with reverse transcriptase

Front 133

what is the emergence of viral diseases due to?

Back 133

1-mutation that alters virus host range or pathogenicity
2-spread of existing viruses from one species to another
3-dissemination of a virus from a small, isolated population to a larger population

Front 134

what do RNA viruses (like influenza) tend to have high mutation rates?

Back 134

because replication of their nucleic acid lacks proofreading

Front 135

what are prions

Back 135

infectious proteins that spread a disease; a misfolded form of a normal brain protein

Front 136

what is genomics?

Back 136

the study of all the genes in an organism and how they function together

Front 137

what is bioinformatics

Back 137

the application of computational methods to the storage and analysis of biological data

Front 138

What are the 3 stages of the Human Genome Project

Back 138

1-genetic (linkage) mapping
2-physical mapping
3-DNA sequencing

Front 139

what is a linkage map (genetic map)

Back 139

it maps the location of several thousand genetic markers on each chromosome

Front 140

what is a genetic marker

Back 140

a gene or other identifiable DNA sequence

Front 141

What are recombination frequencies used for

Back 141

to determine the order and relative distances between genetic markers

Front 142

whats a physical map

Back 142

it expresses the distance between genetic markers, usually as the number of base pairs along the DNA

Front 143

how is a physical map constructed

Back 143

by cutting a DNA molecule into many short fragments and arranging them in order by identifying overlaps

Front 144

what are sequencing machines used for

Back 144

to determine the complete nucleotide sequence of each chromosome

Front 145

what is the whole-genome shotgun approach

Back 145

powerful computer programs are used to order fragments into a continuous sequence

Front 146

what are the 2 approaches to sequencing DNA

Back 146

1-hierarchical sequencing
2-shotgun sequencing

Front 147

what is comparative genomics

Back 147

the analysis and comparison of genomes from different species. the purpose is to gain a better understanding of how species have evolved and to determine the function of genes and non-coding regions of the genome

Front 148

what does conservation in primary sequence predict?

Back 148

conservation in secondary and tertiary structure

Front 149

how many base pairs does the human genome contain

Back 149

about 3 million nucleotide base pairs

Front 150

what is the average gene size

Back 150

about 3000 bases, but sizes vary greatly

Front 151

what is the total number of genes in a human

Back 151

22,000

Front 152

By how much do human DNA sequences differ from one another

Back 152

less than .1%

Front 153

what does the bulk of most eukaryotic genomes consist of

Back 153

noncoding DNA sequences (junk DNA)

Front 154

what are pseudogenes

Back 154

former genes that have accumulated mutations and are nonfunctional

Front 155

what are exons

Back 155

regions of genes coding for protein or giving rise to rRNA and tRNA

Front 156

what is simple sequence DNA

Back 156

contains many copies of tandemly repeated short sequences

Front 157

what is a short tandem repeat (STR)

Back 157

a series of repeating units of 2-5 nucleotides

Front 158

what is the basis of change at the genomic level

Back 158

mutation

Front 159

what is the evolution of the ancestral globin gene

Back 159

1-duplication of ancestral gene
2-mutation in both copies
3-transposition to different chromosomes
-further duplications and mutations

Front 160

what do errors in meiosis result in

Back 160

an exon being duplicated on one chromosome and deleted from the homologus chromosome

Front 161

what happens in exon shuffling

Back 161

errors in meiotic recombination lead to some mizing and matching of exons, either within a gene or between 2 nonallelic genes

Front 162

what may multiple copies of similar transposable elements do

Back 162

facilitate recombination, or crossing over between different chromosomes

Front 163

what can insertion of transposable elements within a protein-coding sequence do

Back 163

block protein production

Front 164

what can insertion of transposable elements within a regulatory sequence do

Back 164

increase of decrease protein production

Front 165

what do comparative studies of genomes do

Back 165

-advance our understanding of the evolutionary history of life
-help explain how the evolution of development leads to morphological diversity

Front 166

what are highly conserved genes

Back 166

genes that have changed very little over time

Front 167

what do highly conserved genes inform us about

Back 167

relationships among species that diverged from each other a long time ago

Front 168

what is the significant difference between mice and humans and chimps?

Back 168

in the structure of genes and the activities of their protein products

Front 169

what is HAR-1

Back 169

rapidly evolving gene thats expressed in the brain & encodes a stable structural RNA that seems to be involved in regulating the expression of many other genes

Front 170

what is HAR2

Back 170

gene that regulates expression in the wrist and thumb during fetal development...contributes to morphological changes required for dexterity

Front 171

what is AMY1

Back 171

salivary amylase, facilitates starch digestion

Front 172

what is LCT

Back 172

lactase, in most species only expressed in nursing infants

Front 173

whats the FOXP2 gene

Back 173

its product turns on genes involved in vocalization

Front 174

what is cancer

Back 174

a growth disorder of cells

Front 175

where do cancers originate from

Back 175

a single cell which has become unable to regulate its growth(replication) and begins to proliferate in an uncontrolled manner, forming a tumor

Front 176

what are tumors characterized by

Back 176

deregulation of cell division and cell death

Front 177

what is tumor caused by

Back 177

either increased cell division or decreased apoptosis

Front 178

what is tumorigenesis

Back 178

a multi-step process by multiple genetic alterations that progressively transform normal cells into malignant cells

Front 179

what are the 6 acquired capabilities of cancer cells

Back 179

1-growth signal autonomy
2-evasion of growth inhibitory signals
3-evasion of apoptosis
4-unlimited replicative potential
5-angiogenesis
6-invasion and metastasis

Front 180

what is mitogenic signaling transmitted to the nucleus via?

Back 180

complex cytoplasmic circuits called "signal transduction" pathways

Front 181

genes that normally regulate cell growth and division during the cell cycle include:

Back 181

-genes for growth factors
-their receptors
-intracellular molecules of signaling pathways

Front 182

what are oncogenes

Back 182

cancer-causing genes

Front 183

what are proto-oncogenes

Back 183

normal cellular genes that code for proteins that stimulate normal cell growth and division

Front 184

A DNA change that makes a proto-oncogene excessively active converts it to what?

Back 184

an oncogene, which may promote excessive cell division and cancer

Front 185

what is Ras

Back 185

the first and foremost human oncogene

Front 186

what is the Ras protein

Back 186

encoded by the ras gene, its a G protein that relays a signal from a growth factor receptor to a cascade of protein kinases

Front 187

what does Ras signaling do

Back 187

upregulates levels of cyclin D, which is required for G1/S transition

Front 188

Deregulating Ras signaling impacts which cellular activities

Back 188

-cytoskeleton cell motility
-translation
-apoptosis
-cell-cell junctions
-endocytosis
-nuclear transport Ca+2 signaling
-membrane trafficking vesicle formation
-transcription
-cell-cycle progression

Front 189

What is apoptosis (programmed cell death)

Back 189

a latent, rapid cell suicide program that is activated by damaged or deranged cells, leading to their elimination

Front 190

what is p53

Back 190

the key effector of the apoptotic response; prevents the proliferation of damaged cells

Front 191

what does p53 do if DNA damage is detected?

Back 191

it initiates DNA repair pathway

Front 192

what does p53 do if damage/stress is prolonged or severe

Back 192

it promotes programmed cell death

Front 193

how does p53 work?

Back 193

it binds to specific DNA sits and activates the expression of certain target genes. The protein products of these target genes are the effectors of the p53 response, which includes cell cycle arrest (withdrawl), DNA repair, & programmed cell death (apoptosis)

Front 194

what genetic changes accompany tumor progression in the colon

Back 194

-loss of tumor suppressor gene APC
-activation of ras oncogene
-loss of tumor suppressor gene DCC
-loss of tumor suppressor p53
-additional mutations

Front 195

what is the plasma membrane

Back 195

the boundary that separates the living cell from its surroundings; it exhibits selective permeability, allowing some substances to cross it more easily than others

Front 196

what are cellular membranes

Back 196

fluid mosaics of lipids and proteins

Front 197

what does amphipathic mean

Back 197

they have both hydrophobic and hydrophilic regions

Front 198

what do membrane lipids include

Back 198

phospholipids and sterols (cholesterol and phytosterols)

Front 199

what is a simple membrane

Back 199

a phospholipid bilayer

Front 200

what part of the protein is hydrophillic

Back 200

the polar and charged amino acids

Front 201

what part of the protein is hydrophobic

Back 201

the nonpolar amino acids

Front 202

what is membrane fluidity

Back 202

membrane lipids drift laterally, and even "flip flop"

Front 203

what is fluorescence photobleaching

Back 203

1-label lipids with a fluorescent "tag"
2-focus a strong beam on a cell surface to bleach the label
3-watch how fast the label comes back from unbleached parts

Front 204

what happens to membranes as temperatures cool

Back 204

membranes switch from a fluid state to a solid state

Front 205

what are integral proteins

Back 205

at least partially inserted into membranes; most completely span out (even several times)

Front 206

what are peripheral proteins

Back 206

attached to the membrane surface, cytoskeleton, ECM but not inserted

Front 207

when is the asymmetrical distribution of proteins, lipids, and associated carbohydrates in the plasma membrane determined

Back 207

when the membrane is built by the ER and Golgi apparatus

Front 208

what are transmembrane proteins

Back 208

integral proteins that span that membrane

Front 209

what are some functions of membrane proteins

Back 209

1)transport
2)enzymatic activity
3)signal transduction
4)intercellular joining
5)cell-cell recognition
6)attachment to the cytoskeleton and extracellular matrix (ECM)

Front 210

how do cells recognize each other

Back 210

by binding to surface molecules, often carbohydrates, on the plasma membrane

Front 211

do hydrophobic (nonpolar) molecules pass through the membrane rapidly?

Back 211

yes

Front 212

do polar molecules cross the membrane easily

Back 212

no

Front 213

what is diffusion

Back 213

the net drift of molecules in the direction of lower concentration due to random thermal movement

Front 214

what happens at dynamic equilibrium

Back 214

many molecules cross one way at cross in the other direction

Front 215

what is passive transport

Back 215

the diffusion of a substance across a membrane without the expenditure of cellular energy

Front 216

what is osmosis

Back 216

the diffusion of water across a selectively permeable membrane

Front 217

what is the direction of osmosis determined by

Back 217

a difference in total solute concentration

Front 218

what is tonicity

Back 218

the ability of a solution to cause a cell to gain or lose water

Front 219

what is an isotonic solution

Back 219

solute concentration is the same as that inside the cell; no net water movement across the plasma membrane

Front 220

what is a hypertonic solution

Back 220

solute concentration is greater than that inside the cell; cell loses water

Front 221

what is hypotonic solution

Back 221

solute concentration is less than that inside the cell; cell gains water

Front 222

what is osmoregulation

Back 222

control of water balance

Front 223

what do cell wall do

Back 223

help maintain water balance

Front 224

what happens to plant cells in a hypertonic environment

Back 224

plant cells lose water & eventually, the membrane pulls away from the cell wall, a usually lethal effect called plasmolysis

Front 225

what is facilitated diffusion

Back 225

transport proteins speed movement of molecules across the plasma membrane

Front 226

what do transport proteins do

Back 226

allow passage of hydrophilic substances across the membrane

Front 227

what are channel proteins

Back 227

transport proteins that have a hydrophilic channel that certain molecules or ions can use as a tunnel

Front 228

what are carrier proteins

Back 228

transport proteins that bind to molecules and change shape to shuttle them across the membrane

Front 229

what is a gated channel

Back 229

a membrane channel whose permeability is regulated;facilitated or mediated transport system

Front 230

what are 2 major types of gated channels involved in the opening of the channel

Back 230

1-voltage-gated channel (response to changes in electrical potential)
2-ligand-gated channel (response to the binding of a molecule, such as a neurotransmitter, to a specific receptor)

Front 231

what is active transport

Back 231

the movement of a solute across a biological membrane such that the movement is directed upward in a concentration gradient (against the gradient) and requires the expenditure of energy

Front 232

what is membrane potential

Back 232

the voltages across each cells' membranes (electrical potential energy from opposite charge seperation)

Front 233

what is the electrochemical gradient

Back 233

2 combined forces which drive the diffusion of ions across the membrane
-a chemical force
-an electrical force

Front 234

what is an electrogenic pump

Back 234

a transport protein that generates the voltage across the membrane (membrane potential)

Front 235

when does cotransport (couples transport) occur

Back 235

when active transport of a solute indirectly drives transport of another solute

Front 236

what does bulk transport across the plasma membrane occur by

Back 236

exocytosis & endocytosis

Front 237

what are vesicles

Back 237

the way in whcich large molecules, such as polysaccharides and proteins, cross the membrane

Front 238

what is exocytosis

Back 238

when the cell secretes (exports) macromolecules by fusion of vesicles with the plasma membrane

Front 239

what happens in endocytosis

Back 239

the cell takes in macromolecules by forming vesicles from the plasma membrane

Front 240

what are 3 types of endocytosis

Back 240

-phagocytes (cellular eating): cell engulfs particle in a vacuole
-pinocytosis (cellular drinking):cell creates sesicle around fluid
-receptor-mediated endocytosis: binding of ligands to receptors triggers vesicle formation

Front 241

what is receptor-mediated endocytosis

Back 241

a process by which specific substances are brought into the cell that are in low concentration or only to be used in specific cell types

Front 242

what is the living cell

Back 242

a miniature chemical factory where thousands of reactions occur; it extracts energy and applies energy to perform work

Front 243

what is metabolism

Back 243

the totality of an organism's chemical reactions

Front 244

what do catabolic pathways do

Back 244

release energy by breaking down complex molecules into simpler compounds

Front 245

what do anabolic pathways do

Back 245

consume energy to build complex molecules from simpler ones

Front 246

what is bioenergetics

Back 246

the study of how organisms manage their energy resources

Front 247

what is energy

Back 247

the capacity to do work

Front 248

what are different forms of energy

Back 248

-heat
-chemical
-electrical
-mechanical
-radiant

Front 249

what id potential energy

Back 249

stored energy; energy that matter possesses because of its location or structure

Front 250

what are examples of potential energy

Back 250

-chemical
-nuclear
-gravitational
-mechanical

Front 251

what is kinetic energy

Back 251

energy of movement

Front 252

what are examples of kinetic energy

Back 252

-electrons
-atomos
-waves
-molecules
-objects

Front 253

what is thermodynamics

Back 253

the study of energy transformations

Front 254

what does the 1st law of thermodynamics state?

Back 254

the energy of the universe is constant; energy can be transferred and transformed, but it cant be created or destroyed

Front 255

what does the 2nd law of thermodynamics state?

Back 255

every energy transfer or transformation increases the entropy (disorder) of the universe, because some energy is always lost, usually as heat.

Front 256

how does energy enter the ecosystem

Back 256

as light

Front 257

how is energy lost in the ecosystem

Back 257

as heat

Front 258

what does the free-energy change of a reaction tell us?

Back 258

whether the reaction occurs spontaneously

Front 259

what needs to happen for a chemical reaction to be spontaneous

Back 259

the reactants must have more potential energy than the products and/or be more ordered than the product

Front 260

when there's high potential energy, is there more or less order?

Back 260

more order

Front 261

what is a living system's free energy (G)

Back 261

energy that is available to do work when temperature and pressure and uniform, as in a living cell

Front 262

How do we determine how a metabolic reaction has changed the free energy of the cell?

Back 262

We measure the change in free energy, delta G

Front 263

what is the change in free energy?

Back 263

G final state - G initial state

Front 264

what is the change is free energy during a process related to

Back 264

the change in enthalpy (delta H), and the change in entropy or disorder (delta S), times the temperature

Front 265

what is the delta G is a negative number

Back 265

the products have less free energy than the reactant and more disorder

Front 266

The delta G needs to be what in order for the process to be spontaneous

Back 266

negative delta G

Front 267

what is free energy a measure of

Back 267

a system's instability, its tendency to change to a more stable state; higher G to lower G

Front 268

what is equilibrium

Back 268

the state of maximum stability

Front 269

whats an exergonic (energy toward) reaction

Back 269

it proceeds with a net release of free energy and is spontaneous

Front 270

what's an endergonic (energy toward) reaction

Back 270

it absorbs free energy from its surroundings and is not spontaneous

Front 271

what three main kinds of work does a cell do

Back 271

-mechanical
-transport
-chemical

Front 272

How do cell manage energy resources to do work

Back 272

by energy coupling, the use of an exergonic process to drive an endergonic one

Front 273

what does ATP do

Back 273

drives endergonic reactions by phosphorylation, transferring a phosphate group to some other molecule, such as a reactant.

Front 274

what are enzymes

Back 274

proteins that carry out most catalysis in living organisms

Front 275

what do enzymes do

Back 275

stabilize associations between substrates (molecules that will undergo a chemical reaction)

Front 276

what is the initial energy needed to start a chemical reaction called

Back 276

the free energy of activation, or activation energy

Front 277

what is a catalyst

Back 277

a chemical agent that speeds up a reaction without being consumed by the reaction

Front 278

what is the active site

Back 278

the region on the enzyme where the substrate binds

Front 279

what is the reactant that an enzyme acts on called

Back 279

the enzyme's substrate

Front 280

what does induced fit mean

Back 280

that many enzymes change shape when they bind to the substrate

Front 281

how can the active site lower an E_A_ barrier?

Back 281

-orienting substrates correctly
-straining substrate bonds
-providing a favorable microenvironment
-covalently bonding to the substrate

Front 282

what's an acid-base catalysis

Back 282

enzyme chain transfer H+ to or from the substrate- a covalent bond breaks

Front 283

what's covalent catalysis

Back 283

a functional group in a side chain bonds covalently with the substrate

Front 284

what's metal ion catalysis

Back 284

metals on side chains loose or gain electrons

Front 285

what are environmental factors that affect enzyme activity

Back 285

-optimal temperature
-optimal pH

Front 286

what are cofactors

Back 286

nonprotein enzyme helpers, usually metal ions, (minerals) found in the active site participating in catalysis

Front 287

what are coenzymes

Back 287

nonprotein organice molecules required for proper enzymatic activity

Front 288

what are inhibitors

Back 288

molecules that bind to an enzyme to decrease enzyme activity

Front 289

what do competitive inhibitors do

Back 289

bind to the active site of an enzyme, competing with the substrate

Front 290

how would chemical chaos result

Back 290

if a cell's metabolic pathways were not tightly controlled

Front 291

what is allosteric regulation

Back 291

a protein's function at one site is affected by binding of a regulatory molecule at another site, called an allosteric site

Front 292

what do allosteric inhibitors do

Back 292

stabilize the inactive form of the enzyme, inhibiting activity

Front 293

what do allosteric activators do

Back 293

stabilize the active form of the enzyme, promoting enzyme activity

Front 294

what is cooperativity

Back 294

a form of allosteric regulation that can amplify enzyme activity

Front 295

what are caspases

Back 295

proteolytic enzymes

Front 296

what is feedback inhibition

Back 296

the switching off of a metabolic pathway by its end product

Front 297

what is photosynthesis

Back 297

the process that converts solar energy into chemical energy

Front 298

how do autotrophs sustain themselves

Back 298

without eating anything derived from other organisms

Front 299

where do heterotrophs obtain their organic material from

Back 299

other organisms

Front 300

what do photoautotrophs do

Back 300

use the energy of sunlight to make organic molecules from the water and carbon dioxide

Front 301

why is only 5% of the sun's energy that reaches the Earth converted into chemical energy?

Back 301

-not all wavelengths absorbed
-much energy is lost during conversion of light energy to chemical energy, and during the carbon fixation reactions

Front 302

what are the 2 sets of reactions that photosynthesis consists of

Back 302

-light dependent reactions
-light independent reactions

Front 303

What do the light-dependent reactions produce

Back 303

O2 from H2O

Front 304

what do light-independent reactions produce

Back 304

sugar from CO2

Front 305

what are light dependent and light independent reactions linked by

Back 305

electrons

Front 306

what are chloroplasts

Back 306

highly structured, membrane-rich organelles

Front 307

what are thylakoids

Back 307

internal vesicle-like structures: these are embedded with photosynthetic pigments, such as chlorophyll

Front 308

what is grana (granum)

Back 308

columns or stacks of thylakoids

Front 309

what is stroma

Back 309

semi-liquid surrounding thylakoids

Front 310

what do light reactions convert

Back 310

solar energy into NADPH & ATP and release molecular oxygen (splitting of water)

Front 311

what does the calvin cycle convert

Back 311

CO2, ATP, and NADPH into sugar (carbon fixation)

Front 312

what is the electromagnetic spectrum

Back 312

the entire range of electromagnetic energy, or radiation

Front 313

what is wavelength

Back 313

the distance between crests of waves

Front 314

what are pigments

Back 314

substances that absorb visible light

Front 315

why do leaves appear green

Back 315

because chlorophyll reflects and transmits green light

Front 316

what is the main photosynthetic pigment

Back 316

chlorophyll a

Front 317

what are accessory pigments called

Back 317

carotenoids

Front 318

what do carotenoids do

Back 318

absorb excessive light that would damage chlorophyll

Front 319

what do accessory pigments like chlorophyll b do

Back 319

broaden the spectrum used for photosynthesis

Front 320

what is an absorption spectrum

Back 320

a graph plotting a pigment's light absorption versus wavelength

Front 321

what is a porphyrin ring

Back 321

light-absorbing "head" of molecule; note magnesium atom at center

Front 322

whats the hydrocarbon tail

Back 322

it interacts with hydrophobic regions of proteins inside thylakoid membranes of chloroplasts; H atoms not shown

Front 323

what is a photon

Back 323

a discrete amount of light energy

Front 324

what happens when a molecule absorbs a protein

Back 324

one of its electrons is elevated to a higher orbital

Front 325

what are photons absorbed

Back 325

when the energy of the photon is equal to the difference between the ground state and the excited state of the electron

Front 326

red photons raise electrons to which state

Back 326

state 1

Front 327

blue photons raise photons to which state

Back 327

state 2

Front 328

what is fluorescence

Back 328

the afterglow when excited electrons fall back to the ground state and photons are given off

Front 329

what is a photosystem

Back 329

a reaction center associated with light-harvesting complexes

Front 330

what are the 2 types of photosystems in the thylakoid membrane

Back 330

1-photosystem II
2-photosystem I

Front 331

photosystem II is best at absorbing what wavelength

Back 331

680 nm

Front 332

photosystem I is best at absorbing what wavelength

Back 332

700 nm

Front 333

what do photosystems I & II have in common

Back 333

both have chlorophyll a; but they're associated with different proteins, which affects their absorption spectra

Front 334

what are the 2 possible routes for electron flow

Back 334

1-cyclic
2-linear

Front 335

what is the predominant route of electron flow & explain

Back 335

Linear (non cyclic) electron flow: light energy drives the synthesis of both NADPH and ATP by energizing both photosysystems in the thylakoid membrane

Front 336

Describe mitochondria

Back 336

-oxidative phosphorylation
-energy of electron comes from food
-protons are pumped from the matrix to the intermembrane space
-ATP is made in the matrix
-ATP is made utilizing NADH

Front 337

Describe chloroplasts

Back 337

-photophosphorylation
-energy of electron comes from sunlight
-protons are pumped from stroma into the thylakoid space
-ATP is made in stroma
-ATP is made without utilizing NADPH

Front 338

what is carbon fixation

Back 338

CO2 is incorporated into organic molecules that are already in the chloroplasts

Front 339

what must happen for net synthesis of one G3P

Back 339

the cycle must take place 3 times, fixing 3 molecules of CO2

Front 340

G3P molecules produced by the Calvin cycle are often used to make what

Back 340

glucose and fructose (combined to form sucrose)

Front 341

what are the main photosynthetic products

Back 341

sucrose & starch

Front 342

what is the energy entering chloroplasts as sunlight stored as

Back 342

chemical energy in organic compounds

Front 343

what does energy flow into the ecosystem as

Back 343

sunlight

Front 344

what does energy leave the ecosystem as

Back 344

heat

Front 345

what does photosynthesis generate

Back 345

O2 and organic molecules, which are used in cellular respiration

Front 346

what is the most important source of chemical potential energy

Back 346

electrons

Front 347

What does hydrolysis of the bond between the 2 outermost phosphate groups result in?

Back 347

formation of ADP and Pi (H2PO-4) in a highly exergonic reaction, with 7.3 kcal of energy released per mole of ATP hydrolyzed

Front 348

what is energy coupling

Back 348

when a reactant is phosphorylated, the exergonic phosphorylation reaction is paired with an endergonic reaction

Front 349

when do endergonic reactions become exergonic

Back 349

when the substrates of enzymes involved are phosphorylated

Front 350

what are reduction-oxidation reactions (redox reactions)

Back 350

a class of chemical reactions that involve the loss or gain of an electron

Front 351

When does an electron lose potential energy

Back 351

when it shifts from a less electronegative atom to a more electronegative atom, therefore the reduced version has more energy than the oxidized one

Front 352

What is the partner that becomes reduced in cellular respiration when glucose is oxidized

Back 352

nicotinamide adenine dinucleotide (NAD+)

Front 353

What is a second electron acceptor in cellular respiration

Back 353

flavin adenine dinucleotide (FAD)

Front 354

what is the 4 step process of cellular respiration

Back 354

1-glucose is broken down to pyruvate
2-pyruvate is processed to form acetyl-CoA
3-Acetyl-CoA is oxidized to CO_2_
4-compounds that were reduced in steps 1-3 (NADH and FADH_2_) are oxidized in reactions that lead to ATP production

Front 355

what is glycolysis

Back 355

a series of 10 chemical reactions, its the first step in glucose oxidation

Front 356

what happens in glycolysis

Back 356

glucose is broken down into 2 3-carbon molecules of pyruvate, and the potential energy released is used to phosphorylate ADP to form ATP

Front 357

what are the 2 major phases of glycolysis

Back 357

-energy investment phase
-energy payoff phase

Front 358

what is an isomerase

Back 358

an enzyme that rearranges a molecule into a structural isomer

Front 359

what is substrate-level phosphorylation

Back 359

when an enzyme transfers a phosphate group from a substrate molecule to ADP

Front 360

what is coenzyme A

Back 360

a cofactor; it accepts acetyl groups and transfers them to substrates

Front 361

where does the citric acid cycle or Krebs cycle take place

Back 361

in the mitochondrial matrix

Front 362

whats the citric acid cycle

Back 362

the acetyl group of acetyl CoA joins the cycle by combining with oxaloacetate, forming citrate. The next 7 steps decompose the citrate back to oxaloacetate, making the process a cycle

Front 363

what is the electron transport chain (ETC)

Back 363

the proteins involved in the redox reactions

Front 364

How does electron transport generate ATP?

Back 364

electron transfer in the electron transport chain causes proteins to pump H+ from the mitochondrial matrix to the intermembrane space

Front 365

what is the H+ in electron transport referred to as

Back 365

a proton-motive force, emphasizing its capacity to do work

Front 366

what is ATP synthase

Back 366

an enzyme complex consisting of an ATPase "knob" component (the F1 unit) and a membrane bound, proton-transporting base component (the F0 unit), connected by a "stalk."

Front 367

what is chemiosmosis

Back 367

the use of energy in a H+ gradient to drive cellular work

Front 368

why is oxygen the most effective electron acceptor

Back 368

because of its high electronegativity

Front 369

what are smaller drops in free energy associated with

Back 369

ATP synthesis

Front 370

what are larger drops in free energy associated with

Back 370

the production of NADH and FADH_2_

Front 371

what is the sequence of energy flow during cellular respiration

Back 371

glucose -> NADH ->electron transport chain -> proton-motive force ->

Front 372

in the absence of O2, how is ATP produced

Back 372

glycolysis couple with fermentation or anaerobic respiration to produce ATP

Front 373

what does fermentation consist of

Back 373

glycolysis plus reactions that regenerate NAD+, which can be reused by glycolysis

Front 374

how much ATP does cellular respiration produce

Back 374

38 ATP per glucose molecule

Front 375

how much ATP does fermentation produce

Back 375

2 ATP per glucose molecule

Front 376

what is a characteristic of obligate anaerobes

Back 376

they carry out fermentation or anaerobic respiration and cant survive in the presence of O2

Front 377

what is a characteristic of facultative anaerobes

Back 377

they can survive using either fermentation or cellular respiration

Front 378

how are fatty acids broken down

Back 378

by beta oxidation and yeield acetyl CoA

Front 379

what is control of catabolism based mainly on

Back 379

regulating the activity of enzymes at strategic points in the catabolic pathway

Front 380

what is overnourishment

Back 380

excessive intake of food energy with the excess stored as fat

Front 381

what does insulin do

Back 381

it promotes transport of glucose into body cells, and stimulates liver and muscle cells to store glucose as glycogen, blood glucose drops

Front 382

what does the pancreas do

Back 382

secretes the hormone glucagon into the blood

Front 383

what does glucagon do

Back 383

it promotes the breakdown of glycogen in the liver and the release of glucose into the blood

Front 384

what is glucagon

Back 384

a peptide hormone (29aa) that is synthesized by the alpha cells of the pancreas

Front 385

what is the primary function of glucagon

Back 385

to increase levels of glucose in the blodd

Front 386

what is cell division

Back 386

a process in which cells make 2 daughter cells that are genetically identical to the parent cell

Front 387

what does cell division require

Back 387

replication of genomic DNA, and then separation of the 2 copies of genomic DNA into daughter cells

Front 388

what are the functions of cell division

Back 388

1-reproduction
2-growth and development
3-tissue renewal

Front 389

A cell cannot divide into 2, 2 into 4, etc. unless which 2 processes alternate?

Back 389

1-doubling the genome (which is the total complement of DNA)
2-separating the duplicated genome into 2 identical halves

Front 390

where does DNA replication begin

Back 390

at the origin of replication

Front 391

why is cell division in eukaryotes more problematic?

Back 391

1-eukaryotes have more than 1 chromosome
2- eukaryotes have much more DNA/unit space

Front 392

what is the eukaryotes' mechanism to separate chromosomes in the nucleus?

Back 392

1-duplication of each chromosome during the S phase of the cell cycle produces a chromosome consisting of 2 identical sister chromatids that are attached
2-condense the chromosomes into a compact form
3-separate the sister chromatids
4-distribute these exact replicas equally between the 2 daughter cells

Front 393

what are the phases that the cell cycle consists of

Back 393

G1=cell growth and preparation of the chromosomes for replication
S=synthesis of DNA (replication)
G2=growth and preparation for chromosomal segreagation
M=2 parts: mitosis (nuclear division) and cytokinesis (division of the cytoplasm)

Front 394

what is mitosis

Back 394

the process by which cells divide their genetic material and nucleus (=nuclear division)

Front 395

what is cytokinesis

Back 395

division of the cytoplasm

Front 396

what are chromosomes

Back 396

a combination of DNA and proteins

Front 397

what is chromatin

Back 397

the DNA-protein complax which is organized and packaged by associated associated proteins
that maintain chromosomal structure and control gene activity

Front 398

what are histones

Back 398

basic proteins, acidic DNA coils tightly around histone core, resembles beads on a string

Front 399

what is nucleosome

Back 399

DNA wrapped around the core of 8 histone proteins

Front 400

what is condensins

Back 400

a complex of proteins which aids the scaffold of proteins

Front 401

what are sister chromatids

Back 401

2 copies of the replicated chromosome

Front 402

what is the centromere

Back 402

constriction in chromosome, contains DNA repeats that bind specific proteins

Front 403

what is kinetochore

Back 403

protein "disc" that will bind mitotic spindle

Front 404

what is cohesin

Back 404

complex of proteins holding replicated chromosomes together, at their centromeres, until they are properly configured for seperation

Front 405

what are the 5 sub-phases of mitosis

Back 405

-prophase
-prometaphase
-metaphase
-anaphase
-telophase

Front 406

what happens just before mitosis begins

Back 406

1-in S phase, chromosomes have been duplicated.
2-the seeds of the mitotic spindle (centrioles) begin to grow

Front 407

what is the centrosome

Back 407

microtubule-organizing center that nucleates the formation of the mitotic spindle

Front 408

what is the mitotic spindle

Back 408

a cytoskeletal machine composed of microtubules and associated proteins

Front 409

what are the 3 classes of microtubules in the fully formed mitotic spindle

Back 409

1-astral
2-kinetochore
3-overlap

Front 410

what happens during prophase

Back 410

the mitotic spindle appears to push the centrosomes away from eachother. The centrosomes are actually propelled toward opposite ends (poles) of the cell by the lengthening of the microtubules between them. chromosomes condense, with sister chromatids joined together

Front 411

what happens during prometaphase

Back 411

the nuclear envelope fragments. the microtubles from the spindle interact with the chromosomes

Front 412

what is the metaphase plate

Back 412

an imaginary plane equidistant between the poles in which the sister chromatids are all arranges in a line. it occurs because the spindle fibers are pushing and pulling one another with and equal and opposite force.

Front 413

what happens during anaphase

Back 413

sister chromatids are suddenly separated and each is pulled toward the pole to which it is attached by spindle fibers. each can now be considered a chromosome

Front 414

what are cohesins

Back 414

proteins that hold sister chromatids together

Front 415

what happens during telophase

Back 415

2 nuclei begin to form, surrounded by the fragments of the parent's nuclear envelope. chromatin become less tightly coiled. cytokinesis begins.

Front 416

what did similar types of fusion experiments demonstrate

Back 416

-if one cell is in S and the other is in G1, the G1 nucleus immediately entered S phase
-if a cell in M phase was fused to any other cell in any other phase, the second nucleus entered mitosis
-conclusion from these and other experiments is that events of the cell cycle are directed by a distinct cell cycle control system, a cyclically operating set of molecules that both triggers and coordinates key events

Front 417

what is a checkpoint

Back 417

the process by which an incomplete upstream event generates a signal that inhibits the initiation of downstream events. a checkpoint in the cell cycle is a critical control point where stop and go signals regulate the cycle.

Front 418

where are the 3 major checkpoints found

Back 418

in the G1, G2, and M phases

Front 419

what may happen if the cell proceeds past a checkpoint

Back 419

-insufficient cell size
-incomplete chromosome replication
-incomplete attachment of chromosomes to microtubules

Front 420

what do checkpoint defects result in

Back 420

-genomic instability
-mutability
-disarray

Front 421

what are the molecules that induce progression through the cell cycle

Back 421

cyclically activated protein kinases

Front 422

what are the 2 types of proteins involved in cell cycle control

Back 422

-cyclins
-cyclin dependent kinases

Front 423

what are cyclins

Back 423

proteins that are produced in synchrony with the cell cycle

Front 424

what forms cyclin-dependent kinases (Cdks)

Back 424

the complex of kinases and cyclin

Front 425

whats an example of an internal signal

Back 425

that kinetochores not attached to spindle microtubules send a molecular signal that delays anaphase

Front 426

why do cancer cells grow out of control

Back 426

-make required growth factors themselves
-have abnormal signaling pathways that fail to convey frowth factor signals or that are constitutively active
-have defects in Cdks or other cell cycle signaling machinery that normally insures DNA replication and mitosis occur only when conditions are favorable

Front 427

what do treatments for metastasizing cancers include

Back 427

high-energy radiation and chemotherapy with toxic drugs

Front 428

why were peas a good experimental system

Back 428

-they're easy and inexpensive to cultivate
-reproduce quickly
-can be raised in a small space, in large numbers
-amenable to genetic analyses
-come in many varieties

Front 429

what does self pollination result in

Back 429

true breeding lines

Front 430

what would Mendel do in a typical breeding experiment

Back 430

he would cross pollinate two contrasting true-breeding varieties. this mating or crossing produces a mixed variety (hybrid) and so is called a hybridization

Front 431

what are the parents in hybridization called

Back 431

the P generation

Front 432

what are the hybrid offspring called

Back 432

the F1 generation

Front 433

what is produced when F1 hybrids self-pollinate

Back 433

F2 generation

Front 434

describe the process of cross-pollination

Back 434

1-remove anthers from one plant
2-collect pollen from a different plant
3-transfer pollen to a stigma of the individual whose anthers have been removed

Front 435

what is a gene

Back 435

a segment of DNA that encodes for a protein or (more accurately) an RNA molecule.

Front 436

what does Mendel's law of segregation state

Back 436

that allele pairs seperate or segregate during gamete formation and randomly unite at fertilization

Front 437

what are the 4 related concepts that contribute to Mendel's model that he proposed to account for his 3:1 pattern

Back 437

1-there are alternative forms for genes called alleles and these different forms account for variations in inherited characters
2- for each character, an organism inherits 2 alleles, one from each parent
3-if 2 alleles at a locus differ, then one, the dominant allele determines the organism's appearance; the other recessive allele has no noticeable effect on the organism's appearance
4-the 2 alleles for each character segregate during gamete production and end up in different gametes

Front 438

what is the punnet square a useful tool for

Back 438

determining the ratios of specific offspring that could be expected from a particular breeding

Front 439

what is an organism having a pair of identical alleles said to be?

Back 439

homozygous for the gene controlling that character

Front 440

what is an organism having the 2 different alleles

Back 440

heterozygous for that gene (Pp)

Front 441

what happens in dihybrid crosses

Back 441

true breeding plants that differed in 2 characteristics were examined

Front 442

what does the law of independent assortment state?

Back 442

that each pair of alleles segregates independently of other pairs of alleles during gamete formation

Front 443

how can we determine probability of any genotype or phenotype

Back 443

by multiplying together the probability of an egg and sperm having a particular allele

Front 444

what is continuous variation

Back 444

the greater the number of genes influencing a character, the more continuous the expected distribution of character variation will be

Front 445

what is incomplete dominance

Back 445

the phenotype of the heterozygote is intermediate between those of the 2 homozygotes

Front 446

what is codominance/multiple allelism

Back 446

2 or more alleles affect the phenotype in seperate distinguishable ways, that is, several alleles are dominant over the recessive

Front 447

what is epistasis

Back 447

non allelic gene interaction that affects phenotype

Front 448

what is pleiotropy

Back 448

the ability of a gene to affect an organisms phenotype in many different ways

Front 449

what is the information content of DNA in the form of?

Back 449

specific sequences of nucleotides

Front 450

what is gene expression

Back 450

the process by which DNA directs protein synthesis, includes 2 stages: transcription & translation

Front 451

what is the "one gene-one enzyme" experiment

Back 451

they irradiated Neurospora with x-rays (which were known to induce mutations) and screened the survivors for mutants which could no longer grow on minimal medium, but could grow on complete medium, and also on minimal medium if it was supplemented with one essential nutrient

Front 452

what is the link between genotype and phenotype

Back 452

proteins

Front 453

what is the central dogma that summarizes the flow of information in cells

Back 453

DNA code for RNA, which codes for proteins.

Front 454

how are the instructions for assembling amino acids into proteins encoded into DNA

Back 454

there are 20 amino acids but there are only 4 nucleotide bases in DNA

Front 455

what is the triplet code

Back 455

a series of non-overlapping, three nucleotide words, called codons. one codon specifies one amino acid.

Front 456

how is the genetic code redundant?

Back 456

because amino acids are specified by more than one codon

Front 457

how is the genetic code unambiguous

Back 457

because any one codon always specifies the same one amino acid

Front 458

what is the reading frame

Back 458

after the start codon, subsequent codons are read in frame as a series of non-overlapping three letter words

Front 459

what does insertion or deletion of a single base pair cause?

Back 459

a "frameshift" mutation that will cause the genetic message to be misread.

Front 460

what is transcription

Back 460

RNA synthesis

Front 461

what is the promotor

Back 461

the DNA sequence where RNA polymerase attaches

Front 462

what is a transcription unit

Back 462

the stretch of DNA that is transcribed

Front 463

what is the transcription initiation complex

Back 463

the completed assembly of transcription factors and RNA polymerase bound to a promoter

Front 464

what happens during initiation

Back 464

after RNA polymerase binds to the promoter, the DNA strands unwind, and the polymerase initiates RNA synthesis at the start point on the template strand

Front 465

what are introns

Back 465

noncoding regions called intervening sequences

Front 466

what are exons

Back 466

other regions that are eventually expressed, usually translated into amino acid sequences

Front 467

what occurs during splicing

Back 467

it removes introns & joins exons, creating an mRNA molecule with a continuous coding sequence

Front 468

what do spliceosomes consist of

Back 468

a variety of proteins and several small nuclear ribonucleoproteins (snRNPs) that recognize the splice sites

Front 469

what is the ribozyme

Back 469

the RNA molecule has enzymatic activity. because it is single stranded, it can form various secondary structures, and specially modified bases contribute to catalytic activity.

Front 470

what is translation

Back 470

the process of protein synthesis using an mRNA template to specify the order of amino acids

Front 471

what does translation require

Back 471

the function of a very large number of mulecules

Front 472

what happens in translation

Back 472

-codons are translated sequentially into amino acids as a ribosome moves along an mRNA
-tRNAs act as adapters, bringing amino acids to the ribosome by the appropriate base pairing between the codon of the mRNA & the anti-codon of tRNA
-each different tRNA has a specific anti-codon that recognizes and base pairs with the codon of the mRNA

Front 473

what do tRNAs function as

Back 473

adaptors in reading information from RNA into synthesis of protein

Front 474

how are molecules of tRNA different?

Back 474

-each carries a specific amino acid on one end
-each has an anticodon on the other end

Front 475

why is each tRNA used repeatedly

Back 475

-to pick up its designated amino acid in the cytosol
-to deposit the amino acid at the ribosome
-to return to the cytosol to pick up another copy of that amino aicd

Front 476

Describe structure of tRNA

Back 476

-short and have characteristic secondary structure called a cloverleaf, which is stabilized by the presence of unusual bases, and intramolecular base pairing
-also contains a 3' CCA tail that is added post-transcriptionally and is the site at which amino acids are attached

Front 477

which 2 regions of tRNA remain single stranded?

Back 477

-the anti-codon
-the 3' amino acid attachment site

Front 478

what are the 3 stages of translation

Back 478

-initiation
-elongation
-termination

Front 479

what are the 3 cavities on the ribosome into which a tRNA fits?

Back 479

E, P site, and A site

Front 480

what are the A & P sites on the ribosome for?

Back 480

for incoming and resident tRNAs

Front 481

what is the E site on the ribosome for

Back 481

outgoing tRNAs

Front 482

what is codon recognition

Back 482

binding of charged tRNA to ribosome A site &hydrogen binding between codon & anti-codon)

Front 483

what happens during the formation of a peptide bond?

Back 483

an rRNA molecule catalyzes the formation of a peptide bond between the polypeptide in the P site (P=peptidy) with the new amino acid in the A site

Front 484

what happens during translocation

Back 484

the ribosome moves along the mRNA, one codon at a time

Front 485

where does protein synthesis begin on free ribosomes?

Back 485

in the cytosol

Front 486

what allows translation to begin in prokaryotic cell while transcription progresses

Back 486

lack of a nuclear envelope

Front 487

hows a eukaryotic cell different from a prokaryotic cell

Back 487

-the nuclear envelope separates transcription from translation
-extensive RNA processing occurs in the nucleus

Front 488

what are mutations

Back 488

changes in the genetic material of a cell or virus

Front 489

what are point mutations

Back 489

chemical changes in just one base pair of a gene

Front 490

what does a change of a single nucleotide in a DNA template strand lead to

Back 490

production of an abnormal protein

Front 491

what are the 2 categories in which point mutation within a gene can be divided into

Back 491

-base-pair substitutions
-base-pair insertions or deletions

Front 492

what does a base-pair substitution do

Back 492

replaces one nucleotide and its partner with another pair of nucleotides

Front 493

what kind of mutations can a base-pair substitution cause

Back 493

silent, missense, or nonsense mutations

Front 494

what is special about silent mutations

Back 494

they do not change the amino acid specified by the codon

Front 495

what is special about missense mutations

Back 495

they still code for an amino acid, but not the right amino acid

Front 496

what is special about nonsense mutations

Back 496

they change an amino acid codon into a stop codon, nearly always leading to a nonfunctional protein

Front 497

what are insertions and deletions

Back 497

additions or losses of nucleotide pairs in a gene

Front 498

what are frame-shift mutations

Back 498

single bases inserted or deleted, usually leads to nonfunctional proteins

Front 499

when can spontaneous mutations occur

Back 499

during DNA replication, recombination, or repair

Front 500

by which mechanisms do mutagens cause mutations

Back 500

-depurination
-deamination
-oxidation

Front 501

what is depurination

Back 501

loss of the purine (A or G) base from the nucleotide

Front 502

what does deamination of cytosine to uracil result in

Back 502

a C:T transition

Front 503

what are ROS (reactive onxygen species)

Back 503

superoxide, hydrogen peroxide, hydroxyl radicals

Front 504

what does UV light form

Back 504

pyrimidine dimers; stable covalent bonds between adjacent pyrimidines

Front 505

what is DNA adducts

Back 505

covalent bond between mutagen and DNA

Front 506

what is organic chemistry

Back 506

the study of compounds that contain carbon

Front 507

what does electron configuration determine

Back 507

the kinds and # of bonds an atom will form with other atoms

Front 508

what are hydrocarbons

Back 508

organic molecules consisting of only carbon & hydrogen

Front 509

what are isomers

Back 509

compounds with the same molecular formula but different structures and properties

Front 510

what are structural isomers

Back 510

have different covalent arrangements of their atoms

Front 511

what are geometric isomers

Back 511

have the same covalent arrangements but differ in spatial arrangements

Front 512

what are enantiomers

Back 512

isomers that are mirror images of each other

Front 513

what are functional groups

Back 513

the components of organic molecules that are most commonly involved in chemical reactions

Front 514

what are the 7 most important functional groups

Back 514

-hydroxyl group
-carboxyl group
-sulfhydryl group
-methyl group
-carbonyl group
-amino group
-phosphate group

Front 515

what are the functional properties of a hydroxyl

Back 515

-polar
-attracts water molecules

Front 516

what are the functional properties of a carbonyl

Back 516

a ketone and an aldehyde may be structural isomers with different properties

Front 517

what are functional properties of carboxyl

Back 517

-has acidic properties
-the covalent bond between oxygen and hydrogen is so polar that hydrogen ions ten to dissociate reversibly

Front 518

what are the functional properties of amino

Back 518

acts as a base; can pick up a proton from the surrounding solution
-ionized with a charge of 1+ under cellular conditions

Front 519

what are the functional properties of sulfhydryl

Back 519

2 sulfhydryl groups can interact to help stabilize protein structure

Front 520

what are the functional properties of phosphate

Back 520

-makes the molecule of which it is a part an anion
-can transfer energy between organic molecules

Front 521

what is ATP?

Back 521

adenosine triphosphate, the primary energy transferring molecule in the cell, it consists of an organic molecule called adenosine attached to a string of 3 phosphate groups

Front 522

How do functional groups contribute to molecules?

Back 522

they contribute to a molecule's solubility, polarity, stability, charge, and/or activity

Front 523

what are the 4 most important atoms which make up 96% of the matter found in organisms

Back 523

hydrogen, carbon, nitrogen, oxygen

Front 524

what are trace elements

Back 524

elements required in minute amounts

Front 525

what is matter

Back 525

anything that takes up space and has mass

Front 526

what makes up matter

Back 526

elements

Front 527

what makes up elements

Back 527

atoms

Front 528

what is an atom

Back 528

the smallest unit of matter that retains the properties of an element

Front 529

what are molecules and compounds

Back 529

when atoms are combines in fixed numbers

Front 530

what makes up the nucleus

Back 530

protons and neutrons

Front 531

what is the neutron charge

Back 531

0

Front 532

what is the proton charge

Back 532

+1

Front 533

what is the electron charge

Back 533

-1

Front 534

what is the atomic #

Back 534

# protons

Front 535

what is the atomic mass

Back 535

# protons + # neutrons in daltons (amu)

Front 536

what are isotopes

Back 536

atomic forms of the same element with different number of nuetrons

Front 537

what are radioactive isotopes valuable as

Back 537

-determining the age of samples
-cytotoxic and mutagenic agents
-induce mutations in DNA
-biological "tracers": radioactive labeling of biological molecules and following their fate in a cell or organism

Front 538

what is energy

Back 538

the capacity to cause change

Front 539

what is potential energy

Back 539

energy that matter had because of its location or structure

Front 540

what is energy level

Back 540

an electron's state of potential energy

Front 541

what is an orbital

Back 541

the 3-dimensional space (path) where an electron is found 90% of the time

Front 542

what are valence electrons

Back 542

electrons in the outermost shell

Front 543

what are elements with a full valence shell

Back 543

chemically inert

Front 544

whats a covalent bond

Back 544

the sharing of a pair of valence electrons by 2 atoms

Front 545

what is electronegativity

Back 545

an atom's attraction for the electrons in a covalent bond

Front 546

whats special about a covalent bond

Back 546

the atoms share the electron equally

Front 547

whats special about a polar covalent bond

Back 547

one atom is more electronegative, and the atoms dont share the electron equally

Front 548

how are ionic bonds in a dry environment

Back 548

strong (salt crystals form)

Front 549

how are ionic bonds in a wet environment

Back 549

weak (salt crystals dissolve in water)

Front 550

when is a hydrogen bond formed

Back 550

when a hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom

Front 551

what are weak chemical bonds called

Back 551

Van der Waals Interactions

Front 552

what is a molecule's shape determined by

Back 552

the positions of its atoms' valence orbitals

Front 553

what are chemical reactions

Back 553

the making and breaking of chemical bonds

Front 554

what are reactants

Back 554

the starting molecules of a chemical reaction

Front 555

what are products

Back 555

the final molecules of a chemical reaction

Front 556

what does polarity allow water molecules to do

Back 556

form hydrogen bonds with each other

Front 557

what are 4 of water's properties that facilitate an environment for life

Back 557

-cohesive behavior
-ability to moderate temperature
-expansion upon freezing
-versatility as a solvent

Front 558

what is cohesion

Back 558

the phenomenon that collectively, hydrogen bonds hold water molecules together

Front 559

what is adhesion

Back 559

an attraction between different substances

Front 560

what is surface tension

Back 560

a measure of how hard it is to break the surface of a liquid

Front 561

what is heat

Back 561

a measure of the total amount of kinetic energy due to molecular motion

Front 562

what is temperature

Back 562

measures the intensity of heat due to average kinetic energy of molecules

Front 563

what can water's high specific heat be traced to

Back 563

hydrogen bonding

Front 564

what is evaporation

Back 564

transformation of a substance from liquid to gas

Front 565

what is heat of vaporization

Back 565

the heat a liquid must absorb for 1g to be converted to gas

Front 566

what is evaporative cooling

Back 566

the process of a liquid evaporating as its remaining surface cools

Front 567

what are substances that dissolve in water called

Back 567

hydrophillic

Front 568

what are substances that don't dissolve in water called

Back 568

hydrophobic

Front 569

what is a colloid

Back 569

a stable suspension of fine particles in a liquid

Front 570

what is a hydration shell

Back 570

a sphere of water molecules which surrounds an ion which is dissolved in water

Front 571

what is molecular weight

Back 571

the sum of all of the weights of all the atoms in a molecule

Front 572

what is a mole

Back 572

the # of grams of a substance that equals its molecular weight

Front 573

what is molarity

Back 573

# of moles of solute per liter of solution

Front 574

what is pH defined by

Back 574

-log[H+]

Front 575

what are buffers

Back 575

solutions in which the pH remains relatively constant when small amounts of acid or base are added

Front 576

what is acid precipitation

Back 576

rain, snow, or fog with a pH lower than 5.2

Front 577

what does a release of CO2 from fossil fuel combustion contribute to

Back 577

-a warming of earth called the "greenhouse" effect
-acidification of the oceans

Front 578

whats a polymer

Back 578

a high molecular weight compound consisting of long chains that may be open, closed, linear, branched, or cross linked

Front 579

do condensation or dehydration reactions require of yield energy?

Back 579

they require energy

Front 580

do hydrolysis reactions require or yield energy

Back 580

yield energy

Front 581

whats a condensation reaction

Back 581

monomer in, water out

Front 582

whats a hydrolysis reaction

Back 582

water in, monomer out

Front 583

whats a carbohydrate

Back 583

a carbon hydrate or hydrated carbon atoms

Front 584

what are the types of carbohydrates?

Back 584

-monosaccharides
-oligosaccharides
-polysaccharides

Front 585

what is the general empirical formula for carbohydrates?

Back 585

(CH2O)n

Front 586

what do mono & disaccharides end in

Back 586

the suffix "ose"

Front 587

when is a disaccharide formed

Back 587

when a dehydration reaction joins 2 monosaccharides

Front 588

what is the bond that holds the disaccharide together called?

Back 588

covalent bond, glycosidic linkage

Front 589

what are the structure and function of a polysaccharide determined by

Back 589

its sugar monomers and the positions of glycosidic linkages

Front 590

what is starch used for

Back 590

energy storage in plant cells

Front 591

what is glycogen used for

Back 591

energy storage in animal cells

Front 592

what is cellulose used for

Back 592

structural support in cell walls of plants and many algae

Front 593

what is cellulose

Back 593

a straight chain polysaccharide composed on glucose molecules linked by means of beta glycosidic bonds

Front 594

what are polysaccharides made from

Back 594

sugar monomers by removal of water (condensation synthesis)

Front 595

what is amylose

Back 595

the form os starch that is composed of long, unbranched chains of glucose units which are joined by means of glycosidic bonds

Front 596

what is amylopectin

Back 596

the form of starch that is composed of long, branched chains of glucose units which are joined by means of alpha and glycosidic bonds

Front 597

what is glycogen

Back 597

a highly branched homopolysaccharide of D-glocose units that is a major form of storage of carbohydrate in animals; the glucose units are linked by means of alpha and alpha glycosidic bonds

Front 598

what is cellulase

Back 598

an enzyme that digests cellulose

Front 599

what is chitin

Back 599

a structural polysaccharide, its found in the exoskeleton of arthropods, it provides structural support for the cell walls of many fungi

Front 600

what are lipids

Back 600

a diverse group of hydrophobic molecules

Front 601

what is the unifying feature of lipids

Back 601

having little or no affinity for water

Front 602

what are the most biologically important lipids

Back 602

-neutral lipids (fats (oils)
-phospholipids
-steroids

Front 603

what are fats constructed from

Back 603

glycerol and fatty acids

Front 604

what is glycerol

Back 604

a 3-carbon alcohol with a hydroxyl group attached to each carbon

Front 605

what does a fatty acid consist of

Back 605

a carboxyl group attached to a long carbon skeleton

Front 606

how do fats form

Back 606

via dehydration reactions

Front 607

what do fats consist of

Back 607

glycerol linked by ester linkages to 3 fatty acids

Front 608

describe saturated fatty acids

Back 608

have the max # of hydrogen atoms possible and no double bonds

Front 609

describe unsaturated fatty acids

Back 609

have one or more double bonds. can be commercially hydrogenated to make margarine or shortening

Front 610

what do waxes contain

Back 610

fatty acids combined with other alcohols and hydrocarbons

Front 611

what is a phospholipid

Back 611

two fatty acids and a phosphate group attached to a glycerol

Front 612

what is amphipathic

Back 612

hydrophobic + hydrophillic

Front 613

how do phospholipids arrange themselves when in an aqueous environment

Back 613

phospholipid bilayer or phospholipid micelle

Front 614

what are steroids

Back 614

lipids characterized by a carbon skeleton consisting of 4 fused rings

Front 615

what are sterols

Back 615

steroids with a polar-OH group on one end, and a non-polar hydrocarbon on the other end

Front 616

what do steroid hormones control

Back 616

development, behavior, and biochemical processes.

Front 617

where does trans fat come from

Back 617

commercial hydrogenation of oils. it changes the texture and shelf-life, but isnt natural & its unhealthy

Front 618

what are the 2 types of nucleic acids

Back 618

deoxyribonucleic acid (DNA)
ribonucleic acid (RNA)

Front 619

what is DNA

Back 619

genetic material that organisms inherit from their parents

Front 620

what does DNA contain

Back 620

the information that cells reuire to function; genes that code for proteins

Front 621

what are the components of nucleotides

Back 621

-nitrogenous base
-pentose sugar
-phosphate

Front 622

what are the 2 families of nitrogenous bases

Back 622

-pyrimidines: have single 6-membered ring
-purines: have a 6-membered ring fused to a 5-membered ring

Front 623

what are sugars

Back 623

poly-hydroxyaldehydes or ketones

Front 624

what is glucose

Back 624

a hexose containing 6 carbon atoms

Front 625

what is ribose

Back 625

a pentose containing 5 carbon atoms

Front 626

how is the nitrogenous base linked to the other ribose sugar

Back 626

through a bond denoted as the N-beta glycosyl bond

Front 627

whats a double helix

Back 627

2 polynucleotides spiraling around an imaginary axis in a DNA molecule

Front 628

whats antiparallel

Back 628

the arrangement in the DNA double helix,where the 2 backbones run in opposite 5'->3' directions from eachother

Front 629

how do the nitrogenous bases in DNA pair up

Back 629

-adenine with thymine
-guanine with cytosine

Front 630

in all cellular DNAs regardless of the species:

Back 630

-the # of adenosine residues is equal to the # of cytidine residues
-the # of guanosine residue is equal to the # of cytidine residues
-sum of purine residues equals sum of pyrimidine residues

Front 631

how are bases from 2 strands held together by

Back 631

hydrogen bonds

Front 632

what is base pairing used for?

Back 632

-preserving info
-repairing mistakes
-transferring info

Front 633

what is the primary structure of RNA

Back 633

single strand of ribonucleotides linked by phosphodiester bonds

Front 634

whats the secondary structure of RNA

Back 634

stem-loop hairpins may form by internal H-bonding

Front 635

what are the chemical differences between DNA & RNA

Back 635

-uracil base vs. thymine base
-ribose sugar vs. deoxyribose sugar

Front 636

what's the function of enzymatic proteins

Back 636

selective acceleration of chemical reactions

Front 637

what's the function of structural proteins

Back 637

support

Front 638

what's the function of storage proteins

Back 638

storage of amino acids

Front 639

what's the function of transport proteins

Back 639

transport of other substances

Front 640

what's the function of hormonal proteins

Back 640

coordination of an organism's activities

Front 641

what's the function of receptor proteins

Back 641

response of cell to chemical stimuli

Front 642

what's the function of contractile and motor proteins

Back 642

movement

Front 643

what's the function of defensive proteins

Back 643

protection against disease

Front 644

what are amino acids

Back 644

organic molecules with carboxyl and amino groups

Front 645

why do amino acids differ in their properties

Back 645

due to different side chains, called R groups

Front 646

what is a protein

Back 646

a polymer of amino acids linked to one another by peptide bonds

Front 647

what is a peptide bond formation called

Back 647

dehydration or condensation

Front 648

what does a functional protein consist of

Back 648

one or more polypeptides twisted, folded, and coiled into a unique shape

Front 649

what determines a protein's 3-dimensional conformation

Back 649

the sequence of amino acids (primary structure)

Front 650

what do the coils and folds of secondary structure result from?

Back 650

hydrogen bonds between repeating constituents of the polypeptide backbone

Front 651

what are the typical secondary structures of proteins

Back 651

-a coil called an alpha helix
-a beta pleated sheet

Front 652

what can depict a protein's conformation

Back 652

ribbon models and space-filling models

Front 653

what is tertiary structure of proteins determined by

Back 653

interactions among various side chains (R groups)

Front 654

what are the possible interaction between R groups?

Back 654

-hydrogen bonds
-ionic bonds
-hydrophobic interactions
-van der Waals interactions

Front 655

what are disulfide bridges

Back 655

strong covalent bonds

Front 656

when does quarternary structure result?

Back 656

when 2 or more polypeptide chains form one macromolecule

Front 657

what is collagen

Back 657

a fibrous protein consisting of 3 polypeptides coiled like a rope

Front 658

what is hemoglobin

Back 658

a globular protein consisting of 4 polypeptides

Front 659

what is sickle-cell disease & what does it result from

Back 659

an inherited blood disorder, results from a single amino acid substitution in the protein hemoglobin

Front 660

what can cause a protein to unravel

Back 660

alternations in pH, salt concentration, temperature, or other environmental factors

Front 661

what is denaturation

Back 661

loss of a protein's native conformation

Front 662

what are chaperonins

Back 662

protein molecules that assist the proper folding of other proteins

Front 663

what has protein mis-folding been implicated in

Back 663

cystic fibrosis, Alzheimer's, and Parkinson's

Front 664

what is the cell theory

Back 664

-all organisms are made of cells
-the cell is the functional unit of life, the simplest collection of matter that can live
-all cells are descended from earlier cells

Front 665

what are the basic features of all cells

Back 665

-plasma membrane
-semifluid substance called cytosol
-chromosomes (carry genes)
-ribosomes (make proteins)

Front 666

what are the 2 types of cells

Back 666

prokaryotic or eukaryotic

Front 667

what is a prokaryote

Back 667

a simple, unicellular organism, such as bacterium, that lacks a discrete nucleus surrounded by a nuclear membrane, and that contains its genetic material within a single chromosome

Front 668

what is a eukaryotic

Back 668

DNA exists in chromosomes, in a nucleus thats bounded by a membranous nuclear envelope. eukaryotic cells have membrane-bound organelles. eukaryotic cells are generally much larger than prokaryotic cells.

Front 669

what are the most common shapes of prokaryotes

Back 669

-spheres (cocci)
-rods (bacilli)
-spirals

Front 670

what do prokaryotic cells lack?

Back 670

nuclei and membrane-bound organelles

Front 671

what is the most important feature of nearly all prokaryotic cells & why

Back 671

their cell wall, which maintains cell shape, provides physical protection, and prevents the cell from bursting in a hypotonic environment

Front 672

what is peptidoglycan

Back 672

a network of sugar polymers cross-linked by polypeptides.

Front 673

what does penicillin do

Back 673

it inactivates the enzyme that cross-links the strands, weakening the cell wall, eventually destroying the cell.

Front 674

what is a capsule

Back 674

an outer sticky, jelly-like coat made of lipo-poly-saccharide around the bacteria

Front 675

what is the gram stain used for

Back 675

for scientists to classify many bacterial species into Gram-positive and Gram-negative groups based on cell wall composition

Front 676

what is different about gram-negative bacteria

Back 676

have less peptidoglycan and an outer membrane that can be toxic, and they are more likely to be antibiotic resistant

Front 677

what is a large surface (cell membrane) needed for

Back 677

for the cell to interact with the environment

Front 678

why are cells divided into compartments

Back 678

to reduce diffusion distances and to separate "incompatible" reactions and their products

Front 679

describe bright-field microscopy

Back 679

light passes directly through these human cells. unless natural pigments are present, there is little contrast and details are not distinguished

Front 680

describe phase-contrast microscopy

Back 680

contrast in the image is increased by emphasizing differences in refractive index (the capacity to bend light), thereby enhancing light and dark regions in the cell.

Front 681

describe differential interference-contrast microscopy

Back 681

it uses 2 beams of polarized light. the combined images look as if the cell is casting a shadow on 1 side

Front 682

describe fluorescence microscopy

Back 682

a natural substance in the cell or a flourescent dye that binds to a specific cell material is stimulated by a beam of light, and the longer wavelength fourescent light is observed coming directly from the eye

Front 683

describe confocal microscopy

Back 683

it uses fluorescent materials but adds a system of focusing both the stimulating and emitted light so that s single plane through the cell is seen.

Front 684

describe stained bright-field microscopy

Back 684

a stain added to preserve cells enhances contrast and reveals details not otherwise visible.

Front 685

what are the 2 basic types of electron microscopes

Back 685

-scanning electron microscopes: focus a beam of electrons onto the surface of a specimen, providing images that look 3D
-transmission electron microscopes (TEMs): focus a beam of electrons through thin sections of a specimen

Front 686

what are TEMs used for

Back 686

mainly to study the internal ultrastructure of cells

Front 687

describe transmission electron microscopy

Back 687

a beam of electrons is focused on the object by magnets. objects appear darker if they absorb the electrons. if the electrons pass through they are detected on a fluorescent screen.

Front 688

describe scanning electron microscopy

Back 688

directs eletrons to the surface of the sample, where they cause other electrons to be emitted. these electrons are viewed on a screen. the 3-dimensional surface of the object can be visualized.

Front 689

describe freeze-fracture microscopy

Back 689

cells are frozen and then a knife is used to crack them open. they crack often passes through the interior of plasma and internal membranes. the "bumps" that appear are usually large proteins embedded in the interior of the membrane

Front 690

what does cell fractionation do

Back 690

it takes cells apart and seperates the major organelles from one another, by size, using high-speed centrifuges

Front 691

what is the plasma membrane

Back 691

the membrane at the boundary of every cell that acts as a selective barrier, thus regulating the cells chemical composition

Front 692

what is the nucleus

Back 692

the genetic library of the cell, contains most of the cell's genes

Front 693

what is chromatin

Back 693

the complex of DNA and protein that makes up the eukaryotic chromosome. when the cell isnt dividing, it isnt visible with a light microscope

Front 694

what is nucleolus

Back 694

a region in the nucleus active in the synthesis of ribosomal RNA and ribosome assembly

Front 695

what is a nuclear envelope

Back 695

the double membrane in eukaryotes that encloses the nucleus separating it from the cytoplasm

Front 696

what is nuclear lamina

Back 696

the nuclear side of the envelope containing protein filaments (intermediate filaments) that maintain the shape of the nucleus

Front 697

what is nuclear pore complex

Back 697

the multi-protein structure forming a channel through the nuclear envelope allowing selected molecules to move between the nucleus and cytoplasm

Front 698

what is a ribosome

Back 698

a particle composed of ribosomal RNA and ribosomal proteins that associates with messenger RNA and catalyzes the synthesis of protein

Front 699

which 2 locations do ribosomes carry out protein synthesis in

Back 699

-in the cytosol (free ribosomes)
-on the outside of the endoplasmic reticulum (ER) or the nuclear envelope (bound ribosomes)

Front 700

what does the endomembrane system do

Back 700

it regulates protein traffic and performs metabolic functions in the cell

Front 701

what are the components of the endo (within) membrane system

Back 701

-nuclear envelope
-endoplasmic reticulum
-golgi apparatus
-lysosomes
-vacuoles
-plasma membrane

Front 702

what is the endoplasmic reticulum

Back 702

a network of membranous tubules and sacs within the cytoplasm of eukaryotic cells, where lipids are synthesized and membrane bound proteins and secretory proteins are made

Front 703

what is the different between smooth ER & rough ER

Back 703

smooth ER lacks ribosomes but rough ER has ribosomes studding its cytosolic surface

Front 704

what is smooth ER involved in

Back 704

lipid synthesis, carbohydrate metabolism, detoxification (liver), calcium storage

Front 705

what is rough ER involved in

Back 705

the synthesis of membrane bound proteins and secretory proteins, which are distributed by transport vesicles

Front 706

what is the golgi apparatus

Back 706

the shipping and recieving center

Front 707

what is cisternae

Back 707

flattened membranous sacs in the golgi apparatus

Front 708

what are the functions of the golgi apparatus

Back 708

-modifies proteins and lipids made in the ER, and sorts and packages them into transport vesicles
-manufactures macromolecules, such as cell wall polysaccharides in plants and extracellular matrix glycosaminoglycans in animal cells.

Front 709

what is a lysosome

Back 709

a membranous sac of hydrolytic enzymes found in animal cells. its produced by the ER + Golgi

Front 710

what is tay-sachs caused by

Back 710

mutation in gene encoding an enzyme that digests gangliosides, a fatty acid found in brain and nerve cells.

Front 711

what are vacuoles

Back 711

membrane-bound sacs with varied functions

Front 712

what are food vacuoles formed by

Back 712

phagocytosis

Front 713

what do contractile vacuoles do

Back 713

pump excess water out of cells

Front 714

what do central vacuoles do

Back 714

hold organic compounds and water

Front 715

what is tonoplast

Back 715

membrane that surrounds the central vacuole

Front 716

what is mitochondria the site of

Back 716

cellular respiration

Front 717

what are chloroplasts the sites of

Back 717

photosynthesis

Front 718

what do mitochondria produce

Back 718

ATP, the cells energy currency

Front 719

whats the structure of mitochondria

Back 719

they have a smooth outer membrane and a higly folded inner membrane. the inner membrane creates 2 compartments: intermembrane space and mitochondrial matrix. the membrane folds, called cristae, present a large surface are for membrane bound enzyme complexes that synthesize ATP

Front 720

what does chloroplast structure include

Back 720

-thylakoids, membranous sacs
-stroma, the internal fluid

Front 721

what is the peroxisome

Back 721

a membrane-bounded organelle that uses molecular oxygen to oxidize organic molecules. in the process, hydrogen peroxide is produced.

Front 722

what are the functions of peroxisome?

Back 722

-detoxification of alcohols and other compounds
-breaking down fatty acids

Front 723

what is the cytoskeleton

Back 723

a network of fibers that organizes structures and activities in the cell

Front 724

what does the cytoskeleton do

Back 724

helps to support the cell and maintain its shape

Front 725

what are the 2 networks that comprise the cytoskeleton

Back 725

-microfilaments
-intermediate filaments
-microtubules

Front 726

what are microtubules

Back 726

hollow rods about 25nm in diameter and variable length

Front 727

what are functions of microtubules

Back 727

-shaping the cell
-guiding movement of organelles

Front 728

what is the centrosome

Back 728

a "microtubule-organizing center: from which spindle microtubules grow out of

Front 729

how do microtubules polymerize (grow) & depolymerize (shrink)

Back 729

by adding and removing heterodimers

Front 730

what are kinesins

Back 730

motor molecules that move various types of vesicles along microtubule tracks.this process is ATP dependent.

Front 731

what does cilia do

Back 731

it circulates fluids, moves egg into oviduct, lines air passages to sweep mucus containing bacteria, pollutants, etc.

Front 732

what is flagella required for

Back 732

sperm motility

Front 733

what is the common ultrastructure that cilia and flagella share

Back 733

a core of microtubules , called an axoneme, sheathed by the plasma membrane

Front 734

what is dynein

Back 734

a motor protein which "walks" along the microtubules causing them to bend

Front 735

what are microfilaments

Back 735

solid rods about 7nm in diameter, built as a twisted double chain of actin subunits

Front 736

what is the structural role of microfilaments

Back 736

to bear tension, resisting pulling forces within the cell

Front 737

what are microfilaments formed by

Back 737

actin subunits

Front 738

what is actin

Back 738

the most abundant intracellular protein in a eukaryotic cell

Front 739

what are the 2 forms in which actin exists

Back 739

-G-actin, a globular monomer
-F-actin, a linear polymer of G-actin subunits

Front 740

what does each actin molecule contain

Back 740

a Mg+2 complexed with either ATP or ADP

Front 741

what is cytoplasmic streaming

Back 741

a circular flow of cytoplasm within cells

Front 742

what do intermediate filaments do

Back 742

support cell shape and fiz organelles, including the nucleus, in place, and are more permanent than MT and MF

Front 743

what are nuclear lamins

Back 743

dense mesh under nuclear envelope that anchors the chromosomes and shapes the nucleus

Front 744

what are vimentins

Back 744

the type of IF found in fibroblasts (connective tissue)

Front 745

what are extracellular structures of the cell

Back 745

-cell walls of plants
-the extracellular matrix (ECM) of animal cells
-intercellular junctions

Front 746

what is the cell wall

Back 746

an extracellular structure that distinguishes plant cells from animal cells;it protects the plant cell, maintains its shape, and prevents uptake of water

Front 747

what are cell wall made of

Back 747

cellulose microfibrils embedded in a matrix of other highly branched polysaccharides and protein

Front 748

what is middle lamella

Back 748

thin layer of "sticky" polysaccharides between primary walls of adjacent cells

Front 749

what are plasmodesmata

Back 749

channels between adjacent plant cells, ions, small molecules pass

Front 750

what are the functions of the ECM (extracellular matrix)

Back 750

-protection
-support
-adhesion
-movement
-regulation

Front 751

what are integrins

Back 751

membrane proteins that connect ECM to cytoskeletal-associated proteins

Front 752

what is glycoprotein

Back 752

large proteins like collagen and fibronectin, with small CHO

Front 753

what happens at tight junctions

Back 753

membranes of neighboring cells are pressed together, preventing leakage of extracellular fluid

Front 754

what do desmosomes (anchoring junctions) do

Back 754

fasten cells together into strong sheets

Front 755

what do gap junctions (communication junctions) do

Back 755

provide cytoplasmic channels between adjacent cells

Front 756

what does the chromosome theory of inheritance state

Back 756

-mendelian genes have specific loci (positions) on chromosomes
-chromosomes undergo segregation and independent assortment

Front 757

what does the law of segregation state

Back 757

that the 2 alleles for each gene separate during gamete formation

Front 758

what does the law of independent assortment state

Back 758

alleles of genes on non homologous chromosomes assort independently during gamete formation

Front 759

where does the first solid evidence associating a specific gene with a specific chromosome come from

Back 759

Thomas Hunt Morgan, an embryologist

Front 760

what make fruit flies a convenient organism for genetic studies

Back 760

-they breed at a high rate
-a generation can be bred every 2 weeks
-they have only 4 pairs of chromosomes

Front 761

what is wild type

Back 761

normal phenotype

Front 762

what are mutant phenotypes

Back 762

traits alternative to the wild type

Front 763

what does the chromosomal theory of inheritance state

Back 763

that genes are present on chromosomes

Front 764

what are linked genes

Back 764

genes located on the same chromosome that tend to be inherited together

Front 765

what is genetic recombination

Back 765

the production of offspring with combinations of traits differing from either parent

Front 766

what are parental types

Back 766

offspring with a phenotype matching one of the parental phenotypes

Front 767

what are recombinant types or recombinants

Back 767

offspring with nonparental phenotypes (new combinations of traits)

Front 768

what does crossing over of homologous chromosomes do

Back 768

it breaks the physical connection between genes on the same chromosome

Front 769

what is a genetic map

Back 769

an ordered list of the genetic loci along a particular chromosome

Front 770

what did Alfred Sturtevant predict about genes

Back 770

that the farther apart 2 genes are, the higher the probablility that a crossover will occur between them and therefore the higher the recombination frequency

Front 771

what is a linkage map

Back 771

a genetic map of chromosome based on recombination frequencies

Front 772

what are cytological maps

Back 772

they indicate the position of genes with respect to chromosomal features

Front 773

what are single nucleotide polymorphisms (SNPs)

Back 773

anonymous markers which can be detected by molecular techniques, such as PCR and DNA sequencing

Front 774

what are hermaphrodites

Back 774

organisms that have both male and female organs and produce both typed of gametes

Front 775

what are dioecious organisms

Back 775

they come in 2 sexes, male or female, and each individual will produce only 1 type of gamete

Front 776

an individual who inherits 2 X chromosomes usually develop as what?

Back 776

a female

Front 777

an individual who inherits an X and a Y chromosome usually develops as what?

Back 777

a male

Front 778

what a SRY

Back 778

sex determining region Y chromosome, its a transcription factor required from testis production

Front 779

what is DAZ

Back 779

another Y chromosome gene required for sperm production

Front 780

what can the differences between Y chromosomes be used for?

Back 780

to establish or reconstruct paternal lineages

Front 781

what is a Barr Body

Back 781

when one X chromosome per cell condenses into a compact object

Front 782

what is a sex-linked gene

Back 782

a gene located on either sex chromosome

Front 783

what does a female need for a recessive sex-linked trait to be expressed?

Back 783

2 copies of the allele

Front 784

what does a male need for a recessive sex-linked trait to be expressed?

Back 784

one copy of the allele

Front 785

what are some disorders caused by recessive alleles on the X chromosome in humans?

Back 785

-color blindness
-duchenne muscular dystrophy
-hemophilia

Front 786

what did James Watson and Francis Crick introduce?

Back 786

an elegant double-helical model for the structure of deoxyribonucleic acid, or DNA

Front 787

what does the DNA program direct the development of?

Back 787

biochemical, anatomical, physiological, and behavioral traits

Front 788

what is the phenomenon transformation?

Back 788

a change in genotype and phenotype due to assimilation of foreign DNA

Front 789

what are bacteriophages (phages)

Back 789

viruses widely used in molecular genetics research

Front 790

what happens during DNA replication

Back 790

the parent molecule unwinds, and 2 new daughter strands are built based on base-pairing rules

Front 791

what does watson and crick's semiconservative model of replication predict?

Back 791

that when a double helix replicates, each daughter molecule will have one old strand and one newly made strand

Front 792

what is conservative replication

Back 792

the original chromosome is copied but remains unchanged. one chromosome is composed of old strands and the other of new strands

Front 793

what is dispersive replication

Back 793

the replication process generates 2 new chromosomes, with new and old sections of DNA mixed together randomly.

Front 794

where does replication begin

Back 794

at the origins of replication, where the 2 DNA strands are separated, opening up a replication "bubble"

Front 795

what is the rate of elongation in bacteria?

Back 795

500 nucleotides per second

Front 796

what is the rate of elongation in human cells?

Back 796

50 per second

Front 797

what is a nucleoside triphosphate

Back 797

each nucleotide that is added to a growing DNA strand

Front 798

what happens as each monomer of dNTP joins the DNA strand?

Back 798

it loses 2 phosphate groups as a molecule of pryophosphate

Front 799

what is the initial nucleotide strand?

Back 799

a short RNA primer

Front 800

what is primase?

Back 800

an enzyme that can start RNA chain from scratch and adds RNA nucleotides one at a time using the parental DNA as a template

Front 801

what is a replication fork?

Back 801

a Y-shaped region where new DNA strands are elongating

Front 802

what are helicases

Back 802

enzymes that untwist the double helix at the replication forks (the protein pulls itself along the DNA strand, mechanically separating the strands, using energy from ATP hydrolysis)

Front 803

what does single-stranded binding protein do

Back 803

it binds to and stabilizes single-stranded DNA until it can be used as a template (these are proteins with "+" charged domains that interact with DNA, and other domains that interact with 1 another)

Front 804

what does topoisomerase do

Back 804

it corrects "overwinding" ahead of replication forks by breaking, swiveling, and rejoining DNA strands

Front 805

what is the lagging strand

Back 805

the other new strand of DNA; it is synthesized as a series of segments called Okazaki fragments, which are joined together by DNA ligase

Front 806

what is the function of the protein helicase

Back 806

unwinds parental double helix at replication forks

Front 807

what is the function of the single-strand binding protein

Back 807

binds to and stabilizes single-stranded DNA until it can be used as a template

Front 808

what is the function of the protein topoisomerase

Back 808

relieves "overwinding" strain ahead of replication forks by breaking, swiveling, and rejoining DNA strands

Front 809

what is the function of the protein primase

Back 809

synthesizes an RNA primer at 5' end of leading strand and of each okazaki fragment ofl agging strand

Front 810

what is the function of the protein DNA pol III

Back 810

using parental DNA as a template, synthesizes new DNA strand by covalently adding nucleotides to the 3' end of a pre-existing DNA strand or RNA primer

Front 811

what is the function of the protein DNA pol I

Back 811

removes RNA nucleotides of primer from f' end and replaces them with DNA nucleotides

Front 812

what is the function of the protein DNA ligase

Back 812

joins 3' end of DNA that replaces primer to rest of leading strand and joins okazaki fragments of lagging strand

Front 813

why can DNA polymerase remove the mismatched base in DNA

Back 813

because its epsilon subunit acts as a 3'-5' exonuclease that removes deoxyribonucleotides from DNA

Front 814

what is a nuclease

Back 814

an enzyme that breaks phosphodiester bonds that join nucleotides

Front 815

when does mismatched repair occur?

Back 815

when mismatched bases remain after DNA synthesis is complete. mismatch repair enzymes recognize the mismatched pair, remove a section of the newly synthesized strand that contains the incorrect base, and fill in the correct bases.

Front 816

what are telomeres

Back 816

bona fide DNA ends that dont prevent the shortening of DNA molecules, but they do postpone the erosion of genes near the ends of DNA molecules

Front 817

how have cancer cells attained immortality?

Back 817

by overexpressing the gene that encodes an enzyme called telomerase

Front 818

what happens during recombinant DNA?

Back 818

nucleotide sequences from 2 different sources, often 2 species are combines in vitro into the same DNA molecule

Front 819

what do restriction enzymes do

Back 819

recognize DNA sequences termed restriction (cleavage) sites

Front 820

what is palindromes

Back 820

when it is the same sequence read 5' to 3'

Front 821

why can any 2 restriction fragments be joined together

Back 821

because they have complementary overhangs (single-stranded) regions that are stabilized by hydrogen bonding

Front 822

what does cloning a gene mean?

Back 822

that a gene (or piece of DNA) is isolated, ligated into a suitable cloning vector, and amplified

Front 823

what are plasmids

Back 823

double stranded circular DNA, the most common cloning bectors

Front 824

what must a cloning vector contain to be useful?

Back 824

-origins of replication (E. coli)
-selectable marker
-unique restriction sites to allow ligation of fragment

Front 825

what is a genomic library

Back 825

a collection of recombinant molecules which represent the entire genome of an organism

Front 826

what is a bacterial artificial chromosome (BAC)

Back 826

a large plasmid that has been trimmed down and can carry a large DNA insert

Front 827

what do cDNA libraries contain?

Back 827

recombinant fragments that correspond only to the small portion of the genome that is actually expressed

Front 828

how is a complementary DNA (cDNA) library made?

Back 828

by cloning DNA made in vitro by reverse transcription of all the mRNA produced by a particular cell

Front 829

what a gel electrophoresis

Back 829

a technique that uses a gel as a molecular sieve (filter) to separate nucleic acids or proteins by size

Front 830

what is hybridization

Back 830

a phenomenon in which your DNA of interest is denatured and allowed to re-anneal with a "probe" which is complementary to it

Front 831

what is an expression vector

Back 831

a cloning vector that contains a highly active prokaryotic promoter

Front 832

what 3 step cycle brings about a chain reaction that produces an exponentially growing population of identical DNA molecules

Back 832

heating, cooling, and replication

Front 833

what 3 steps does each PCR involve?

Back 833

-denaturation
-annealing of primers
-DNA synthesis

Front 834

what sources has PCR amplified DNA from?

Back 834

-tiny amount of blood, seme, saliva, skin cells, hair follicles, etc found at crime scenes
-single embryonic cells for rapid prenatal diagnosis of genetic disorders
-DNA of viral genes from cell infected with difficult to detect viruses such as HIV or hepatitis viruses
-fragments of ancient DNA

Front 835

what do some polymorphisms have to do with?

Back 835

the copy number of STR's (short tandem repeats)

Front 836

how can relatively short DNA fragments by sequenced?

Back 836

by the dideoxy chain termination method

Front 837

what do DNA microarray assays do

Back 837

compare patterns of gene expression in different tissues, at different times, or under different conditions

Front 838

what happens during in vitro mutagenesis

Back 838

mutations are introduced into a cloned gene, altering or destroying its function

Front 839

how can gene expression be silenced?

Back 839

using RNA interference (RNAi)

Front 840

what does organismal cloning produce?

Back 840

one or more organisms genetically identical to the "parent" that donated the single cell

Front 841

what is a totipotent cell

Back 841

a cell that can generate a complete new organism

Front 842

what happens during nuclear transplantation

Back 842

the nucleus of an unfertilized egg cell or zygote is replaced with the nucleus of a differentiated cell

Front 843

what is a stem cell

Back 843

a relatively unspecialized cell that can reproduce itself indefinitely and differentiate into specialized cells of one or more types

Front 844

what are embryonic stem cells

Back 844

stem cells isolated from early embryos at the blastocyst stage

Front 845

what is the aim of stem cell research

Back 845

to supply cells for the repair of damaged of diseased organs

Front 846

what is gene therapy

Back 846

-the alteration of an afflicted individual's genes as a means of disease treatment

Front 847

what requirement is there for gene therapy of somatic cells to be permanent

Back 847

the cells that recieve the normal allele must be the ones that multiply throughout the patient's life

Front 848

what are vectors used for

Back 848

delivery of genes into specific types of cell

Front 849

what medically important proteins can be produced in bacteria?

Back 849

-human insulin
-atrial peptides
-interferon
-tissue plasminogen activator
-human growth hormone

Front 850

how are transgenic animals made

Back 850

by introducing genes from one species into the genome of another animal

Front 851

what are transgenic animals

Back 851

pharmaceutical "factories", producers of large amounts of otherwise rare substance for medical use

Front 852

what can genetic engineering be used for

Back 852

to modify the metabolism of microorganisms

Front 853

what is EnviroPig engineered for

Back 853

to carry the gene for the enzyme phytase, which breaks down phosphorus in feed and reduces excretion of harmful phosphates in the environment

Front 854

why has adoption of genetically modified (GM) crops resisted in some areas?

Back 854

because of questions abouot
-crop safety for human consumption
-movement of genes into wild relatives
-loss of biodiversity