Examkrackers Mcat Bio

Front 1

each amino acid in a polypeptide chain is referred to as a ______

Back 1

residue

Front 2

the major component of extracellular matrix

Back 2

proteoglycans

Front 3

cytochromes

Back 3

carry out electron transport in the ETC

proteins which require a prostetic heme group to function

Front 4

conjugated proteins

Back 4

proteins containing nonproteinaceous components

Front 5

glycogen

Back 5

storage form of glucose, synthesized by liver. mostly found in muscle and liver cells.

Except for digestive tract and kidney, all cells absorb glucose via facilitated diffusion.

Front 6

insulin

Back 6

increases the rate of facilitated diffusion for glucose and other monosaccharides.

Front 7

in the absence of insulin, only ______ and ______ cells are capable of absorbing sufficient amounts of glucose via the facilitated transport system

Back 7

neural and hepatic

Front 8

plants form ______ and ________ from glucose

Back 8

starch and cellulose

Front 9

2 forms of starch

Back 9

amylose and amylopectin

Front 10

minerals

Back 10

the dissolved inorganic ions inside and outside the cell.

assist in the transport of substances entering and exiting the cell by creating electrochemical gradients across membranes.

can give strength to a matrix, such as hydroxyapatite in bone.

act as cofactors

Front 11

cofactors

Back 11

a nonprotein component that assists enzyme or protein function

Front 12

coenzymes

Back 12

organic cofactors. often vitamins or vitamin derivatives.

Front 13

cosubstrates

Back 13

reversibly bind to a specific enzyme, and transfer some chemical group to another substrate.

Cosubstrate is then reverted to its original form.

Front 14

what distinguishes cosubstrates from normal substrates?

Back 14

the cosubstrate reverts to its original form.

Front 15

an enzyme w/out its cofactor is called _________

Back 15

an apoenzyme

Front 16

an enzyme w/ its cofactor is called _________

Back 16

holoenzyme

Front 17

the classic indication of a competitive inhibitor

Back 17

overcoming inhibition by increasing substrate concentration

Front 18

zymogen / proenzyme

Back 18

an inactive form of enzyme. specific peptide bonds are cleaved to irreversibly activate them.

Front 19

positive cooperativity

Back 19

the first substrate changes the shape of the enzyme, allowing other substrates to bind more easily

at low substrate concentrations, small increases in substrate concentration increase enzyme efficiency as well as reaction rate.

Front 20

lyase / synthase

Back 20

enzyme that catalyzes addition rxns w/out use of energy

Front 21

ligase / synthetase

Back 21

enzyme that catalyzes addition rxn, but requires energy from ATP or some other nucleotide

Front 22

kinase

Back 22

an enzyme which phosphorylates something

Front 23

phosphatase

Back 23

an enzyme which dephosphorylates something

Front 24

anabolism

Back 24

molecular synthesis

Front 25

catabolism

Back 25

molecular degradation

Front 26

substrate level phosphorylation

Back 26

glycolysis and Kreb cycle.

the formation of ATP from ADP using the energy released from the decay of high energy phosphorylated compounds as opposed to using the energy from diffusion.

Front 27

acetyl CoA

Back 27

produced inside the mitochondrial matrix from pyruvate in a rxn that produced NADH and CO2

a coenzyme which transfers two carbons from pyruvate to the 4-carbon oxaloacetic acid

Front 28

Each turn of the Kreb cycle produced:

Back 28

1 ATP, 3 NADH, 1 FADH2, 2 CO2

oxaloacetic acid reproduced to start cycle over again

Front 29

fatty acids and amino acids enter metabolic pathway as:

Back 29

acetyl CoA

Front 30

glycerol of triglyerides is converted to _______

Back 30

PGAL

Front 31

proton-motive force

Back 31

the proton gradient across the inner membrane of the mitochondria

Front 32

oxidative phosphorylation

Back 32

production of ATP through the propulsion of protons across the mitochondrial membrane through ATPase

Front 33

products and reactants of cellular respiration

Back 33

glucose + O2 --> CO2 + H2O

Front 34

gene

Back 34

a series of DNA nucleotides that codes for the production of a single polypeptide or mRNA, rRNA, or tRNA

Front 35

euchromatin

Back 35

regions of eukaryotic DNA that are being actively transcribed by a cell

Front 36

heterochromatin

Back 36

tightly packed regions of eukaryotic DNA that are not actively transcribed.

repetitive sequence DNA found here

Front 37

genome

Back 37

the entire DNA sequence of an organism

Front 38

The Central Dogma

Back 38

DNA --> RNA --> protein

Front 39

each nucleotide is bound to the next by a __________

Back 39

phosphodiester bond

Front 40

the end 3' carbon is attached to _______

Back 40

an -OH (hydroxyl) group

Front 41

the end 5' carbon is attached to a __________

Back 41

phosphate group

Front 42

replisome

Back 42

a group of proteins that governs DNA replication

Front 43

SSB tetramer / helix destabilizer proteins

Back 43

prevent the single strand in the loop from folding back onto itself

Front 44

exonuclease

Back 44

one of the subunits in DNA polymerase that proofreeds and removes / repairs nucleotides on the strand

Front 45

telomeres

Back 45

repeated nucleotide units on the end of eukaryotic chromosomal DNA that protect the chromosomes from being eroded through repeated rounds of replication

Front 46

promoter

Back 46

a sequence of DNA nucleotides that designates a beginning point for transcription

Front 47

consensus sequence

Back 47

the most commonly found nucleotide sequence of a promoter recognized by the RNA polymerase of a given species

Front 48

variation from the consensus sequence causes...

Back 48

causes RNA polymerase to bond less tightly and less often to a given promoter, which leads to those genes being transcribed less frequently.

Front 49

transcription requires a _________, while replication requires a ___________

Back 49

promoter, primer

Front 50

template / antisense strand

Back 50

the DNA strand which is transcribed.

Front 51

coding / sense strand

Back 51

DNA strand which is not transcribed. protects its partner against degradation

Front 52

activators and repressors

Back 52

proteins which regulate gene expression at the level of transcription.

bind to DNA close to the promoter and activate or repress the activity of RNA polymerase

Front 53

operon

Back 53

the genetic unit usually consisting of the operator, promoter, and genes that contribute to a single prokaryotic mRNA

Front 54

activators and repressors are often allosterically regulated by...

Back 54

small molecules such as cAMP

Front 55

enhancers

Back 55

regulatory proteins in eukaryotes. function similar to activators and repressors, but act at greater distance from the promoter.

Front 56

primary transcript

Back 56

the initial mRNA nucleotide sequence arrived at through transcription

Front 57

the primary transcript is processed in 3 ways:

Back 57

1) addition of nucleotides
2) deletion of nucleotides
3) modification of nitrogenous bases

Front 58

5' cap

Back 58

serves as an attachment site in protein synthesis and as a protection against degradation by exonucleases

Front 59

poly A tail

Back 59

the polyadenylated 3' end protecting against degradation by exonucleases

Front 60

spliceosome

Back 60

a complex formed from snRNPs associating w/ proteins

recognize nucleotide sequences at the end of introns and excise introns, splicing the exons together

Front 61

restriction enzymes

Back 61

cut nucleic acid at certain nucleotide sequences along the strand

Front 62

palindromic

Back 62

reads the same backwards and forwards.

typically, a restriction site will be palindromic

Front 63

recombinant DNA

Back 63

artificially recombined DNA

Front 64

vector

Back 64

a plasmid or infective virus that is used to place recombinant DNA into a bacterium

Front 65

probe

Back 65

the radioactively labeled complementary sequence of the desired DNA fragment

Front 66

complementary DNA (cDNA)

Back 66

mRNA is reverse transcribed using reverse transcriptase

adding DNA polymerase to cDNA produces a double strand of the desired DNA fragment w/out introns.

Front 67

polymerase chain reaction (PCR)

Back 67

1) DNA heated to denature
2) cooled --> primers anneal to complementary ends of DNA
3) polymerase added w/ supply of nucleotides --> new DNA

Front 68

southern blot

Back 68

identifies fragments of known DNA in a larger population of DNA

Front 69

northern blot

Back 69

identifies fragments of known RNA in a larger population of RNA

Front 70

restriction fragment length polymorphism (RFLP)

Back 70

identifies individuals (as opposed to genes)

based on premise that DNA of different individuals possesses varying distances btwn restriction sites

Front 71

degenerative

Back 71

more than one series of three nucleotides may code for any amino acid

Front 72

unambiguous

Back 72

any single series of three nucleotides will code for one and only one amino acid

Front 73

start codon

Back 73

AUG

acts as a codon for the amino acid methionine.

Front 74

stop codons

Back 74

UGA, UAA, UAG

U Go Away, U Are Away, U Are Gone

Front 75

initiation

Back 75

tRNA sequesters the amino acid methionine and settles it at the P site. this is the signal for the large subunit to join and form the initiation complex.

Front 76

translocation

Back 76

an elongation step in which the ribosome shifts 3 nucleotides along the mRNA toward the 3' end.

Front 77

termination

Back 77

stop / nonsense codon reaches A site. proteins known as release factors bind to the A site allowing a water molecule to add to the end of the polypeptide chain

Front 78

Proteins injected into the ER lumen are destined to become __________

Back 78

membrane-bound proteins

Front 79

signal peptide

Back 79

a 20 amino acid sequence near the front of the polypeptide that is recognized by a protein-RNA signal-recognition particle

Front 80

signal-recognition particle

Back 80

carries the ribosome complex to a receptor protein on the ER. protein grows across the membrane, where it is released into the lumen or remains partially attached to the ER.

Front 81

mutagens

Back 81

physical or chemical mutations that increase the frequency of mutation above the frequency of spontaneous mutation.

Front 82

point mutation

Back 82

a mutation that changes a single base-pair of nucleotides in a double strand of DNA.

Front 83

base-pair substitution mutation

Back 83

one type of point mutation in which one base pair is replaced by another

Front 84

transition mutation

Back 84

a base-pair substitution in which A-T is switched for G-C or the opposite

Front 85

transversion mutation

Back 85

a base-pair substitution that involves a reversal of the same base pairs.

Front 86

missense mutation

Back 86

a base-pair mutation that occurs in the amino acid coding sequence of a gene

Front 87

neutral mutation

Back 87

a mutation that causes no change in protein function

Front 88

silent mutation

Back 88

a mutation in which the amino acid is not changed

Front 89

frameshift mutation

Back 89

results when deletions or insertions occur in multiples other than 3. result in nonfunctional protein.

Front 90

nonsense mutation

Back 90

a mutation in which a base-pair substitution or an insertion or deletion creates a stop codon

Front 91

duplication

Back 91

occurs when a DNA fragment breaks free of one chromosome and incorporates into a homologous chromosome

Front 92

translocation

Back 92

when a segment of DNA from one chromosome is inserted into another chromosome

Front 93

inversion

Back 93

the orientation of a section of DNA is reversed on a chromosome

Front 94

transposition

Back 94

DNA segments can excise themselves from a chromosome and reinsert themselves at another location

Front 95

wild type

Back 95

the original state of the organism

Front 96

forward mutation

Back 96

changes the organism even more from its original state

Front 97

backward mutation

Back 97

reverts the organism back to its original state

Front 98

proto-oncogenes

Back 98

stimulate normal growth in human cells

Front 99

oncogenes

Back 99

mutated proto-oncogenes that cause cancer

Front 100

carcinogens

Back 100

mutagens that cause cancer

Front 101

histones

Back 101

globular proteins around which sections of DNA that are not in use are wrapped

Front 102

nucleosome

Back 102

formed from 8 histones wrapped in DNA

Front 103

chromatin

Back 103

the entire DNA / protein complex

Front 104

heterochromatin

Back 104

condensed chromatin. cannot be transcribed in this form

Front 105

euchromatin

Back 105

chromatin that can be uncoiled and transcribed. only coiled during nuclear division

Front 106

which 2 cell types remain in G0 permanently?

Back 106

neurons and muscle cells

Front 107

the G2 checkpoint checks for ____________

Back 107

mitosis promoting factor (MPF)

Front 108

asters

Back 108

part of the spindle apparatus. microtubules radiating from the centrioles

Front 109

centromeres

Back 109

a group of proteins located toward the center of the chromosome from which the kinetochore microtubules grow

Front 110

kinetochore

Back 110

a structure of protein and DNA located at the centromere of the joined chromatids of each chromosomes

Front 111

disjunction

Back 111

the split of sister chromatids during anaphase

Front 112

spermatogonium / oogonium

Back 112

diploid. germ cells b/f undergoing meiosis.

Front 113

primary spermatocyte / oocyte

Back 113

the germ cell after replication occurs in the S phase of interphase

Front 114

secondary spermatocyte / oocyte

Back 114

haploid. germ cells after cytokinesis following telophase I.

Front 115

reduction division

Back 115

describes meiosis I

Front 116

nondisjunction

Back 116

if during anaphase I or II the centromere of any chromosome does not split.

Front 117

capsid

Back 117

protien coat on a virus

Front 118

virion

Back 118

a mature virus outside the host cell

Front 119

how viruses are different from living organisms

Back 119

1) require host to reproduce
2) do not metabolize organic nutrients (use ATP from host)
3) not separated from external environment by membrane
4) possess either DNA or RNA, but never both
5) can be crystallized w/out losing ability to infect

Front 120

receptor

Back 120

a site on the host onto which the virus attaches. usually a specific glycoprotein on the host cell membrane.

Front 121

bacteriophage

Back 121

a virus that infects bacteria. nucleic acid injected through the tail after viral enzymes have digested a hole in the cell wall.

Front 122

lytic infection

Back 122

cell produces new viruses until it bursts

Front 123

eclipse period

Back 123

the period from infection to when the first fully formed virion appears

Front 124

latent period

Back 124

the period from infection to lysis

Front 125

virulent virus

Back 125

a virus following a lytic cycle

Front 126

lysogenic infection

Back 126

viral DNA is incorporated into the host genome, or

DNA is reverse transcribed from RNA and then incorperated into host's genome

Front 127

temperate virus

Back 127

a virus in a lysogenic cycle

Front 128

provirus

Back 128

a virus that is dormant / latent. viral DNA is incorporated into host DNA

Front 129

prophage

Back 129

a dormant / latent virus whose host cell is a bacterium

Front 130

plus-strand RNA

Back 130

proteins can be directly translated from the RNA.

Front 131

retroviruses

Back 131

carry reverse transcriptase in order to create DNA from RNA. DNA is then incorperated into the genome of the host cell.

Front 132

minus-strand RNA

Back 132

the complement to mRNA. must be transcribed to plus-RNA before being translated

Front 133

viroids

Back 133

small rings of naked RNA w/out capsids. only infect plants

Front 134

prions

Back 134

naked proteins. capable of reproducing themselves, w/out DNA or RNA

Front 135

antibodies

Back 135

bind to a viral protein

Front 136

cytotoxic T-cell

Back 136

destroy infected cells

Front 137

vaccine

Back 137

an injection of antibodies or an injection of a nonpathogenic virus w/ the same capsid or envelope, that allows the host immune system to create its own antibodies

Front 138

archaea

Back 138

have similarities to eukaryotes

unlike bacteria, the cell walls are not made from peptidoglycan

Front 139

fixing CO2

Back 139

reducing it and using the carbon to create organic molecules through the Calvin cycle

Front 140

autotrophs

Back 140

organisms capable of using CO2 as their sole source of carbon

Front 141

heterotrophs

Back 141

use preformed, organic molecules as their source of carbon

Front 142

phototrophs

Back 142

organisms that use light as their energy source

Front 143

chemotrophs

Back 143

organisms that use oxidation of organic or inorganic matter as their energy source

Front 144

nitrogen fixation

Back 144

the process by which N2 is converted to ammonia

Front 145

nitrification

Back 145

creates nitrates, which are useful to plants, from ammonia

Front 146

inclusion bodies

Back 146

granules of organic or inorganic matter that may be visible under a light microscope

Front 147

amphipathic

Back 147

having both polar and nonpolar regions.

describes phospholipids, glycolipids, etc.

Front 148

micelle

Back 148

a spherical structure formed from amphipathic molecules in an aqueous solution.

Front 149

liposome

Back 149

a vesicle surrounded and filled by aqueous solution. contains a lipid bilayer.

Front 150

integral / intrinsic proteins

Back 150

amphipathic proteins that transverse the membrane from the inside of the cell to the outside

Front 151

peripheral / extrinsic proteins

Back 151

situated entirely on the surfaces of the membrane. ionically bonded to integral proteins or the polar group of a lipid

Front 152

role of cholesterol in membranes

Back 152

moderates membrane fluidity

Front 153

hopanoids

Back 153

reduce fluidity of the membrane in prokaryotes

Front 154

Brownian motion

Back 154

random movement of molecules

Front 155

chemical concentration gradient

Back 155

a gradual change in concentration of a compound over a distance

Front 156

electrical gradient

Back 156

applies to molecules w/ a charge.

points in the direction that a positively charged particle will tend to move.

Front 157

semipermeable membrane

Back 157

slows, but does not stop, diffusion

Front 158

two aspects of a compound that affect its semipermeability:

Back 158

size and polarity

Front 159

passive diffusion

Back 159

diffusion in which molecules move through leakage channels across the membrane due to random motion

Front 160

transport / carrier proteins

Back 160

proteins embedded in the membrane that are designed to facilitate the diffusion of specific molecules across the membrane

Front 161

facilitated diffusion

Back 161

diffusion occurs down electrochemical gradient through carrier proteins

Front 162

selectively permeable

Back 162

the ability of a membrane to select btwn molecules of similar size and charge using facilitated diffusion

Front 163

active transport

Back 163

movement of a compound against its electrochemical gradient. requires expenditure of energy in the form of ATP.

Front 164

peptidoglycan

Back 164

makes up the cell wall

Front 165

gram-positive bacteria

Back 165

stain purple b/c they have thick peptidoglycan cell wall that prevents the gram stain from leaking out.

Front 166

periplasmic space

Back 166

the space btwn the plasma membrane and the cell wall in gram+

the space btwn the two plasma membranes in gram-

Front 167

gram-negative bacteria

Back 167

appear pink when stained b/c thin peptidoglycan cell wall allows most of gram stain to be washed off.

have second phospholipid bilayer outside cell wall. it contains lipopolysaccharides which protect from antibodies and antibiotics

Front 168

fimbriae

Back 168

short tenticles which attach a bacterium to a solid surface

not involved in cell motility

Front 169

bacterial flagella are composed of _______

Back 169

flagellin

Front 170

source of energy for flagellum propulsion

Back 170

energy comes from a proton gradient rather than by ATP

Front 171

binary fission

Back 171

bacterial asexual reproduction.

works like DNA replication.

Front 172

plasmid

Back 172

a small circle of DNA that exists and replicates independently of the bacterial chromosome

Front 173

conjugation

Back 173

the transfer of a replicated plasmid through a sex pilus btwn two bacteria

Front 174

F plasmid / fertility factor

Back 174

a bacterial DNA sequence that codes for the sex pilus that allows conjugation

Front 175

R plasmid

Back 175

donates resistance to certain antibiotics

Front 176

transformation

Back 176

the process by which bacteria may incorporate DNA from their external environment into their genome

Front 177

transduction

Back 177

capsid of bacteriophage mistakenly encapsulates a DNA fragment of host cell, then injects harmless bacterial DNA fragments into host cell.

Front 178

vector

Back 178

the virus that mediates transduction

Front 179

endospore

Back 179

allows gram-negative bacteria to lay dormant when there is a lack of nutrients.

must be activated b/f it can germinate and grow. endospore activated by heating. germination triggered by nutrients.

Front 180

fungi

Back 180

eukaryotic heterotrophs that obtain their food by absorption rather than by injestion.

Front 181

saprophytic

Back 181

to live off dead organic matter

Front 182

septa

Back 182

fungal cell walls.

perforated to allow for cytoplasmic streaming

Front 183

septa are made of _________

Back 183

the polysaccharide chitin

Front 184

hyphae

Back 184

multiply branched threadlike structures of the fungal growth state

Front 185

mycelium

Back 185

a tangled mass of hyphae

Front 186

fungal DNA state is mostly:

Back 186

haploid stage predominates, and is the fungal growth state.

Front 187

spores

Back 187

haploid structures that give rise to new mycelia.

Front 188

yeast

Back 188

single-celled fungi. rarely produce sexually by producing spores.

Front 189

budding / sexual fission

Back 189

a small cell pinches off from the single parent cell.

the most common form of asexual reproduction in yeast.

Front 190

the two mating types of mycelia:

Back 190

+ and -

Front 191

when does asexual vs. sexual reproduction occur in fungi?

Back 191

asexual reproduction occurs when conditions are good, sexual reproduction occurs when conditions are tough

Front 192

nuclear pores

Back 192

RNA can exit nucleus through nuclear pores, but DNA cannot

Front 193

phagocytosis

Back 193

proteins on the particulate matter bind to proteins on the cell --> matter is engulfed

only occurs in a few specialized cells

Front 194

pinocytosis

Back 194

extracellular fluid is engulfed by invagination of the cell membrane.

performed in most cells, and in a random fashion; nonselective

Front 195

receptor mediated endocytosis is associated w/ which protein

Back 195

clathrin

Front 196

how does phagocytosis differ from receptor-mediated endocytosis

Back 196

the purpose of receptor mediated endocytosis is to absorb the ligands

in phagocytosis, the ligands exist only as signals to initiate phagocytosis of other particles

Front 197

cisternal space / ER lumen

Back 197

the space inside the ER

Front 198

in the Golgi apparatus, proteins are distinguished based upon which 2 things?

Back 198

the signal sequence and carbohydrate chains

Front 199

if a protein doesn't have a signal sequence,...

Back 199

they are packaged into secretory vesicles and expelled from the cell

Front 200

secretory vesicles

Back 200

protein filled vesicles which expel proteins from the cell through exocytosis

may also contain enzymes, growth factors, or extracellular matrix components

act as the vehicle w/ which to supply the cell membrane w/ its integral proteins and lipids, and as a mechanism for membrane expansion

Front 201

smooth ER

Back 201

produces triglycerides.
cholesterol formation --> steroid production
produces phospholipids
detoxification of foreign substances

Front 202

peroxisomes

Back 202

self-replicating (vs. budding off membranes)

detoxification, oxygen concentration regulation, synthesis and breakdown of lipids, metabolism of nitrogenous bases and carbohydrates.

Front 203

microfilaments

Back 203

squeeze the membrane together in phagocytosis and cytokinesis

Front 204

axoneme

Back 204

the major portion of each eukaryotic flagellum and cilium containing microtubules in a 9 + 2 arrangement

Front 205

dynein

Back 205

the protein which makes up the cross bridges connecting each of the outer pairs of microtubules to their neighbor.

allows for movement of microtubules --> movement of flagella and cilia

Front 206

prokaryotic flagella are made from ______

Back 206

a thin strand of a single protein called flagellin

Front 207

centrosome

Back 207

the major microtubule-organizing center in animal cells

Front 208

centrioles

Back 208

function in the production of flagella and cilia, but are not necessary for microtubule production

Front 209

the major component of microfilaments is __________

Back 209

actin

Front 210

cytoplasmic streaming

Back 210

responsible for amoeba-like movement. caused by microfilament movement.

Front 211

tight junctions

Back 211

act as fluid barrier around cell

Front 212

desmosomes

Back 212

join two cells at a single point.

Front 213

gap junctions

Back 213

tunnels btwn cells allowing for the exchange of small molecules and ions.

Front 214

collagen

Back 214

the structural protein that gives cartilage and bone their tensile strength

Front 215

axon hillock

Back 215

generates an action potential in all directions if the electrical stimulus is from the signal received at the dendrites is great enough

Front 216

action potential

Back 216

a disturbance in the electric field across the membrane of a neuron

Front 217

the resting potential is established by...

Back 217

an equilibrium btwn passive diffusion of ions across the membrane and the Na/K pump

Front 218

depolarization

Back 218

voltage gated sodium channels open, allowing Na to flow into the cell, reversing the polarity of the membrane potential so that it is positive inside relative to the outside

Front 219

repolarization

Back 219

voltage gated sodium channels close, voltage gated potassium channels open. K+ flows out of the cell making the inside more negative.

Front 220

hyperpolarization

Back 220

inside of membrane becomes more negative than the resting potential b/c potassium channels are slow to close.

Front 221

electrical synapses

Back 221

composed of gap junctions btwn cells. transmit signal faster than chemical synapses and in both directions.

Front 222

chemical synapse

Back 222

unidirectional; slowest step in the transfer of a nervous signal. when action potential reaches synapse, Ca2+ flows into cell, causing neurotransmitters to be released into synaptic cleft

Front 223

Brownian motion

Back 223

the random motion of molecules. the means by which neurotransmitters diffuse across the synaptic cleft

Front 224

means by which cell prevents overstimulation: (3 things)

Back 224

1) neurotransmitter destroyed by enzyme in matrix of synaptic cleft and its parts recycled by presynaptic cleft

2) neurotransmitter directly absorbed by presynaptic cleft via active transport

3) neurotransmitter may diffuse out of synaptic cleft

Front 225

second messenger system

Back 225

binding of neurotransmitter to receptor activates another molecule inside the cell to make changes

Front 226

myelin

Back 226

electrically insulating sheaths. increases the rate at which an axon can transmit signals.

formed from oligodendrocytes in the CNS

formed from Schwann cells in the PNS

Front 227

sensory neurons are located ______

Back 227

dorsally from the spinal cord

Front 228

motor neurons are located __________

Back 228

ventrally

Front 229

nerves

Back 229

neuron processes (axons and dendrites) that are bundled together

Front 230

somatic nervous system

Back 230

designed primarily to respond to the external environment. contains sensory and motor functions. its motor neurons innervate only skeletal muscle.

voluntary control

Front 231

autonomic nervous system

Back 231

generally involuntary

Front 232

sympathetic

Back 232

"fight or flight" response

part of ANS

Front 233

parasympathetic

Back 233

"rest and digest" response

part of ANS

Front 234

the neurotransmitter used by the somatic and parasympathetic nervous systems

Back 234

acetylcholine

Front 235

the neurotransmitter used by the sympthetic nervous system

Back 235

epinephrine or norepinephrine

Front 236

part of the brain integrating subconscious activities

Back 236

lower brain, consisting of the medulla, hypothalamus, thalamus, and cerebellum

Front 237

cerebrum / cerebral cortex

Back 237

the higher brain; stores memories and processes thoughts

Front 238

cornea

Back 238

the first place light strikes the eye. most bending of light occurs here.

Front 239

when the ciliary muscle contracts...

Back 239

the lens becomes more like a sphere and brings its focal point closer to the lens

Front 240

the image on the retina is _______ and ___________

Back 240

real and inverted

Front 241

iris

Back 241

the colored portion of the eye which creates the opening called the pupil. controls how much light enters the eye.

Front 242

tympanic membrane

Back 242

the eardrum. separates the external auditory canal from the middle ear.

Front 243

cochlea

Back 243

detects sound. hair cells and organ or Corti transduce movement into neural signals

Front 244

semicircular canals

Back 244

detect orientation and movement of the head

Front 245

peptide hormones

Back 245

water soluble, and thus move freely through the blood

have difficulty diffusing through the cell membrane of the effector --> attach to membrane bound receptors instead of diffusing through the membrane

Front 246

second messenger

Back 246

activates or deactivates enzymes and/or ion channels and creates a cascade of chemical rxns that amplifies the effect of the hormone

Front 247

steroid hormones come from...

Back 247

the adrenal cortex, the gonads, or the placenta

Front 248

tyrosine hormones

Back 248

the thyroid hormones and the catecholamines

Front 249

peptide hormones come from...

Back 249

pituitary, parathyroid, and pancreas

Front 250

steroid hormones

Back 250

require protein transport molecule to dissolve in blood stream

diffuse through cell membrane of effector, combine w/ receptor in cytosol, transported to nucleus where steroid acts on transcription

typical effect is to increase # of a certain protein

Front 251

where in cell tyrosine derivative hormones are formed:

Back 251

formed by enzymes in the cytosol or on the rough ER

Front 252

thyroid hormones

Back 252

lipid soluble --> carried through blood by proteins.

bind to receptors in nucleus, increasing transcription of genes

Front 253

hypothalamus

Back 253

controls the release of anterior pituitary hormones

Front 254

hormones released by the anterior pituitary

Back 254

human growth hormone (hGH)
adrenocorticotropin (ACTH)
thyroid-stimulating hormone (TSH)
follicle-stimulating hormone (FSH)
leutinizing hormone (LH)
prolactin

Front 255

adrenocorticotropic hormone

Back 255

a peptide which stimulates the adrenal cortex to release glucocorticoids via the secondary messenger system using cAMP. Release stimulated by stress.

Front 256

glucocorticoids

Back 256

stress hormones

Front 257

thyroid-stimulating hormone

Back 257

stimulates the thyroid to release T3 and T4 via the second messenger system using cAMP.

Front 258

prolactin

Back 258

promotes milk production of the breasts

Front 259

hormones produced by the posterior pituitary

Back 259

oxytocin and antidiuretic hormone (ADH)

Front 260

oxytocin

Back 260

increases uterine contractions during childbirth and causes milk to be ejected from the breasts

Front 261

antidiuretic hormone (ADH) / vasopressin

Back 261

causes the collecting ducts of the kidneys to become permeable to water, reducing the volume of urine and concentrating the urine.

b/c fluid reabsorbed, increases blood pressure

Front 262

adrenal cortex secretes:

Back 262

only steroid hormones; aldosterone and cortisol

Front 263

mineral corticoids

Back 263

one type of steroid hormone secreted by the adrenal cortex

affect the electrolyte balance in the blood stream

think aldosterone

Front 264

glucocorticoids

Back 264

one type of steroid hormone secreted by the adrenal cortex

increase blood glucose concentration and effect fat and protein metabolism

think cortisol

Front 265

aldosterone

Back 265

a mineral corticoid that acts in the distal convoluted tubule and collecting duct to increase Na and Cl adsorption and K and H secretion.

creates net gain of particles in the plasma, which results in an eventual increase in blood pressure.

Front 266

cortisol

Back 266

a glucocorticoid that increases blood glucose levels by stimulating the creation of glucose and glycogen in the liver.

degrades fat and proteins. a stress hormone

Front 267

catecholamines

Back 267

tyrosine derivatives synthesized in the adrenal medulla.

epinephrine and norepinephrine
"fight or flight" stress hormones

Front 268

T3 and T4

Back 268

increase the basal metabolic rate (resting metabolic rate)

lipid soluble tyrosine derivatives synthesized in the thyroid

Front 269

calcitonin

Back 269

a peptide hormone released by the thyroid gland which decreases blood calcium level by decreasing osteoclast activity.

Front 270

endocrine hormones of the pancreas:

Back 270

insulin and glucagon

Front 271

insulin

Back 271

released when blood levels of carbohydrates or proteins are high.

stimulates storage of carbohydrates as glycogen, fat as adipose tissue, and amino acids as proteins

increases permeability of cells to glucose and amino acids

Front 272

parathyroid hormone

Back 272

increases blood calcium levels by stimulating proliferation of osteoclasts

Front 273

epididymus

Back 273

where the sperm matures and is stored until ejaculation

Front 274

semen is composed of fluid from... (3 things)

Back 274

the seminal vesicles, the prostate, and the bulbourethral glands

Front 275

all the eggs of the female are arrested as ___________ at birth

Back 275

primary oocytes

Front 276

zona pellucida

Back 276

a viscous substance secreted around the primary oocyte at puberty

Front 277

upon stimulation of ________, theca cells secrete ______

Back 277

LH, androgen

Front 278

androgen is converted to _________ in the presence of ____________

Back 278

estradiol (a type of estrogen) in the presence of FSH

Front 279

estradiol

Back 279

a steroid hormone that prepares the uterine wall for pregnancy

Front 280

luteal surge

Back 280

just before ovulation, estradiol level rises rapidly, causing an increase in LH secretion. this causes ovulation

Front 281

ovulation

Back 281

bursting of the follicle

Front 282

corpus luteum

Back 282

the follicle left behind after ovulation. secretes estradiol and progesterone throughout pregnancy or for 2 wks after ovulation

Front 283

corpus albicans

Back 283

a degraded corpus luteum that results if the egg is not fertilized

no longer secretes estrogen or progesterone

Front 284

once fertilization occurs, the oocyte...

Back 284

goes through the second meiotic division to become an ovum and releases a second polar body

Front 285

what stage of development is the egg in when implants in the uterus?

Back 285

the blastocyst stage

Front 286

human chorionic gonadotropin (HCG)

Back 286

a peptide hormone secreted by the egg upon implantation. prevents the degradation of the corpus luteum

Front 287

determination

Back 287

cells become determined to give rise to a particular tissue early on.

Front 288

differentiation

Back 288

the specialization that occurs at the end of the development, forming a specialized tissue cell

Front 289

induction occurs when...

Back 289

one cell type affects the direction of differentiation of another cell type

Front 290

mucous cells

Back 290

secrete mucus to lubricate the stomach walls so that food can slide along easily and to protect the epithelial lining from the acidic environment of the stomach

Front 291

chief cells

Back 291

secrete pepsinogen, the zymogen precursor to pepsin

Front 292

pariental cells

Back 292

secrete HCl

Front 293

G cells

Back 293

secrete gastrin, a large peptide hormone which is absorbed into the blood and stimulates parietal cells to secrete HCl

Front 294

acetylcholine

Back 294

increases the secretion of all gastric cell types

Front 295

gastrin and histamine

Back 295

increase HCl secretion into the stomach

Front 296

digestion in the small intestine occurs in the __________

Back 296

duodenum

Front 297

absorption in the small intestine occurs in the...

Back 297

jejunum and ileum

Front 298

brush border

Back 298

the microvilli that cover the intestinal wall, increasing surface area

Front 299

goblet cells

Back 299

epithelial cells which secrete mucus to lubricate the intestine and help protect the brush border from mechanical and chemical damage

Front 300

the fluid in the duodenum has a pH of _______ due to _______

Back 300

6 due to bicarbonate ions secreted from the pancreas

Front 301

all enzymes released by the pancreas are _________

Back 301

zymogens

Front 302

trypsin and chymotrypsin

Back 302

degrade proteins into small carbohydrates

Front 303

bile

Back 303

produced by the liver and stored in the gall bladder

emulsifies fat, increasing the surface area for lipase

Front 304

large intestine

Back 304

water and electrolyte absorption

contains symbiotic E coli bacteria which produce vitamins

Front 305

glucose is dragged into the enterocyte by __________

Back 305

sodium

Front 306

in all cells except _______ and ________, glucose is transported down its concentration gradient via facilitated diffusion

Back 306

enterocytes and cells of the renal tubule

Front 307

byproduct of gluconeogenesis from proteins

Back 307

ammonia, which is converted to urea by the liver and then excreted in the urine by the kidney

Front 308

fatty acids combine immediately once they reach the blood w/ _______

Back 308

albumin

Front 309

VLDLs

Back 309

transport triglycerides from the liver to adipose tissue

Front 310

intermediate and low-density lipoproteins

Back 310

transport cholesterol and phospholipids to somatic cells

Front 311

functions of the liver

Back 311

blood storage, blood filtration (of bacteria), carbohydrate metabolism, fat metabolism, protein metabolism, detoxification, erythrocyte destruction, vitamin storage

Front 312

when the liver mobilizes fat or protein for energy, the blood...

Back 312

acidity increases

Front 313

function of the kidney

Back 313

to excrete waste products, maintain homeostasis of body fluid volume and solute composition, and to help control plasma pH

Front 314

urine is created in the kidney and emptied into the ___________

Back 314

renal pelvis

Front 315

the renal pelvis is emptied by the _________

Back 315

ureter

Front 316

the first capillary bed of the nephron

Back 316

glomerulus

Front 317

Bowman's capsule and the glomerulus make up the __________

Back 317

renal corpuscle

Front 318

fenestrations

Back 318

holes in the glomerular epithelium through which hydrostatic pressure forces plasma into Bowman's capsule. screen out blood and large proteins from entering Bowman's capsule.

Front 319

proximal tubule

Back 319

takes filtrate after Bowman's capsule. where most reabsorption takes place by means of secondary active transport proteins

Front 320

antiport

Back 320

an integral membrane transport protein that simultaneously transports two different molecules in opposite directions across a membrane

Front 321

the net result of the proximal tubule is to...

Back 321

reduce the amount of filtrate in the nephron while changing the solute composition w/out changing the osmolarity

Front 322

loop of Henle

Back 322

dips into the medulla from the proximal tubule. functions to increase the solute concentration, and thus the osmotic pressure, of the medulla.

Front 323

permeability of descending loop of Henle

Back 323

permeable to water, but not to salts

Front 324

permeability of ascending loop of Henle

Back 324

impermeable to water, permeable to salts

Front 325

distal tubule

Back 325

reabsorbs Na+ and Ca2+ while secreting K+, H+, and HCO3-

net effect is to lower filtrate osmolarity

Front 326

aldosterone

Back 326

acts on distal tubule cells to increase sodium and potassium membrane transport proteins

Front 327

ADH

Back 327

increase the permeability of the collecting tubule to water. makes collecting duct permeable to water

Front 328

juxtaglomerular apparatus

Back 328

monitors filtrate pressure in the distal tubule

Front 329

filtration occurs in the _______

Back 329

renal corpuscle

Front 330

reabsorption and secretion occurs mostly in the ___________

Back 330

proximal tubule

Front 331

concentrates solute in the medulla

Back 331

loop of Henle

Front 332

distal tubule enters into the __________

Back 332

collecting duct

Front 333

concentrates the urine

Back 333

collecting duct

Front 334

pneumonic for ADH

Back 334

Always Digging Holes (in the collecting duct)

Front 335

renin

Back 335

secreted in the juxtaglomerular apparatus. stimulates the adrenal cortex to secrete aldosterone.

Front 336

systole

Back 336

occurs when the ventricles contract

Front 337

diastole

Back 337

occurs during relaxation of the entire heart and then contraction of the atria

Front 338

vagus nerve

Back 338

innervates the SA node, slowing the contractions of the heart

Front 339

which part of the cardiovascular system is wrapped in smooth muscle

Back 339

arteries and arterioles

Front 340

diaphragm

Back 340

skeletal muscle. innervated by phrenic nerve. creates negative gauge pressure in the thoracic cavity when contracted.

Front 341

epiglottis

Back 341

prevents food from entering the trachea during swallowing

Front 342

the oxygen dissociation curve is shifted to the right by... (3 things)

Back 342

an increase in carbon dioxide pressure, hydrogen ion concentration, or temperature

Front 343

a shift of the oxygen dissociation curve to the right indicates...

Back 343

a lowering of hemoglobin's affinity for oxygen

Front 344

most carbon dioxide is carried through the blood in what form?

Back 344

as a bicarbonate ion

Front 345

the bicarbonate ion formation is governed by the enzyme ________

Back 345

carbonic anhydrase

Front 346

when bicarbonate moves into the erythrocyte, __________ moves out

Back 346

Cl-

Front 347

fluid is propelled through the valves in 2 ways:

Back 347

smooth muscle contracts, and skeletal muscle squeezes during movement

Front 348

albumin

Back 348

transports fatty acids and steroids, acts to regulate osmotic pressure of blood.

Front 349

the majority of leukocytes are _________

Back 349

neutrophils

Front 350

T helper cells

Back 350

assist in activating B-lymphocytes as well as killer and suppressor T cells.

Front 351

the lumen of the sarcoplasmic reticulum is filled w/:

Back 351

Ca2+

Front 352

the myosin head is released from the active site when...

Back 352

ATP attaches to the myosin head

Front 353

the force of a contracting muscle depends upon... (2 things)

Back 353

the number and size of the active motor units, and the frequency of action potentials

Front 354

myoglobin

Back 354

an oxygen storing protein similar to hemoglobin, but having only one protein subunit.

Front 355

slow-twitch muscle fibers

Back 355

red from large amounts of myoglobin. contain large amounts of mitochondria.

split ATP at a slow rate --> slow to fatigue, but also have a slow contraction velocity

postural muscles

Front 356

fast-twitch A muscle fibers

Back 356

split ATP at a fast rate --> contract rapidly.

Front 357

fast-twitch B muscle fibers

Back 357

low myoglobin content, contract rapidly, contain large amounts of glycogen

Front 358

"growth" of new muscle

Back 358

does NOT undergo mitosis

when exposed to forceful, repetitive contractions, diameter of muscle fibers increases, number of sarcomeres and mitochondria increases, sarcomeres lengthen.

Front 359

skeletal muscle

Back 359

multinucleated. under voluntary control. striated.

Front 360

cardiac muscle

Back 360

striated. involuntary. mononucleated. separated by intercalated disks containing gap junctions. mitochondria larger and more numerous than in skeletal muscle.

Front 361

action potential plateau

Back 361

the action potential of cardiac muscle exhibits a plateau after depolarization. the plateau is created by slow voltage-gated calcium channels which allow calcium to enter and hold the inside of the membrane at a positive potential difference.

plateau lengthens the time of contraction.

Front 362

smooth muscle

Back 362

involuntary, innervated by autonomic nervous system. mononucleated.

contain intermediate filaments attached to dense bodies spread throughout the cell. contraction of actin and myosin causes intermediate filaments to pull the dense bodies together.

Front 363

spongy bone

Back 363

contains red bone marrow.

Front 364

compact bone

Back 364

hold yellow bone marrow.

Front 365

Haversian canals

Back 365

tunnels burrowed by osteoclasts in compact bone

Front 366

lamellae

Back 366

concentric rings formed by osteoblasts

Front 367

canaliculi

Back 367

canals through which osteocytes trapped btwn the lamellae exchange nutrients

Front 368

Volkmann's canals

Back 368

crossing canals which connect Haversian canals

Front 369

Haversian canals contain...

Back 369

blood and lymph vessels

Front 370

osteon / Haversian system

Back 370

the entire system of lamellae and Haversian canal

Front 371

most calcium in the blood is...

Back 371

not in the form of free calcium ions, but is bound mainly by proteins, and to a lesser extent, by phosphates and other anions.

Front 372

hydroxyapatite

Back 372

stores most of the body's Ca2+. give bone strength.

Front 373

collagen

Back 373

give bone strength

Front 374

cartilage

Back 374

flexible, resistant connective tissue. primarily composed of collagen. contains no blood vessels or nerves except in its outside membrane.

Front 375

epidermis

Back 375

avascular (no blood vessels).

Front 376

dermis

Back 376

embedded by blood vessels, nerves, glands, and hair follicles. Collagen and elastic fibers provide skin w/ strength, extensibility, and elasticity.

Front 377

mendelian ratio

Back 377

3:1 ratio dominant to recessive

Front 378

phenotype

Back 378

the expression of a trait

Front 379

genotype

Back 379

an individual's genetic makeup

Front 380

locus

Back 380

the position on respective chromosomes

Front 381

law of segregation

Back 381

alleles segregate independently of each other when forming gametes. any gamete is equally likely to possess any allele.

Front 382

inbreeding

Back 382

mating relatives. does not change the frequency of alleles, but does increase the number of homozygous individuals w/in a population

Front 383

outbreeding

Back 383

mating of nonrelatives which produces hybrids or heterozygotes

Front 384

law of independent assortment

Back 384

genes located on different chromosomes assort independently of each other

in other words, genes that code for different traits, when located on different chromosomes, do not affect each other during gamete formation

Front 385

karyotype

Back 385

a map of the chromosomes

Front 386

Barr body

Back 386

the inactive X chromosome in an inactive somatic cell

Front 387

gene pool

Back 387

the total of all alleles in a population

Front 388

evolution

Back 388

a change in the gene pool

Front 389

order of taxonomical classification

Back 389

kingdom, phylum, class, order, family, genus, species

Front 390

plants and fungi use _______ instead of _________

Back 390

divisions instead of phyla

Front 391

the subphylum vertebrata is in the phylum _________

Back 391

chordata

Front 392

three domains

Back 392

bacteria, archaea, and eukarya

Front 393

species

Back 393

all organisms that can reproduce fertile offspring w/ each other

Front 394

niche

Back 394

the way in which a species exploits its environment

Front 395

fitness

Back 395

the organism which can best survive to reproduce fertile offspring.

Front 396

r-selection

Back 396

involves producing large numbers of offspring that mature rapidly w/ little or no prenatal care.

high brood mortality rate.

population growth curves are exponential. found in unpredictable, rapidly changing environments.

Front 397

K-selection

Back 397

small brood size w/ slow maturing offspring and strong parental care.

sigmoidal growth curve which levels off at the carrying capacity.

Front 398

speciation

Back 398

the process by which new species are formed.

begins when gene flow ceases btwn two sections of a population. factors include geographic, seasonal, and behavioral isolation.

Front 399

adaptive radiation

Back 399

occurs when several separate species arise from a single ancestral species.

Front 400

evolutionary bottleneck

Back 400

occurs when a species faces a crisis so severe as to cause a shift in the allelic frequencies of the survivors of the crisis.

Front 401

divergent evolution

Back 401

when species evolving from the same group maintain a similar structure from the common ancestor

Front 402

convergent evolution

Back 402

when species independently evolve similar structures

Front 403

polymorphism

Back 403

the occurrence of distinct forms of a phenotype (height, flower color, etc)

Front 404

symbiosis

Back 404

a relationship btwn two species

Front 405

mutualism

Back 405

a relationship that is beneficial for both species

Front 406

commensalism

Back 406

beneficial for one species and does not affect the other

Front 407

when a population is in Hardy-Weinberg equilibrium...

Back 407

there is no change in the gene pool

Front 408

requirements of a Hardy-Weinberg equilibrium: (5 things)

Back 408

1. large population
2. mutational equilibrium
3. immigration or emigration must not change gene pool
4. random mating
5. no selection of the fittest

Front 409

genetic drift

Back 409

in small populations, random events cause the death of all members having a certain allele

Front 410

Urey-Miller experiment

Back 410

one of the early experiments attempting to recreate the atmosphere of early earth

Front 411

coacervates

Back 411

lipid or protein bilayer bubbles. the first cells are thought to have evolved from them. spontaneously form and grow from fat molecules suspended in water.

Front 412

the earliest organisms

Back 412

existed 3.6 billion years ago. probably heterotrophs subsisting on preformed organic compounds.

Front 413

filled the atmosphere w/ oxygen

Back 413

photosynthetic bacteria evolved 2.3 billion years ago

Front 414

deuterostomes

Back 414

organisms whose anus develops from or near the blastopore

Front 415

coelom

Back 415

a body cavity w/in mesodermal tissue

Front 416

chordata

Back 416

possess a notocord, pharyngeal slits, a dorsal hollow nerve cord, and a tail

Front 417

vertebrae

Back 417

a subphylum of chordata that has the notochord replaced by a segmented cartilage or bone structure. have a distinct brain enclosed in a skull.