Biology Of The Cell Exam 2

Front 1

a molecule that is made from a long chain of 20 amino acids, each linkes to its neighbor through a covalent peptide bond.

Back 1

protein

Front 2

Protein is also called what?

Back 2

polypeptides

Front 3

formed from the repeating sequence of atoms along the polypeptide chain

Back 3

polypeptide backbone

Front 4

the part of the amino acids in a protein that are not involved in form the peptide bond.

Back 4

side chain

Front 5

the ____ allows for ratation around it and therefore the protein can fold and orient the R groups in facorable positions

Back 5

peptide bond

Front 6

weak ____ interactions will hold the protein in its functional shape

Back 6

non-covalent

Front 7

what are some of the non-covalent interaction the will hold the protein in its functional shape?

Back 7

hydrogen bonds, ionic bonds, and van der waals attractions

Front 8

the protein's ___ will help detemine the conformation in an aqueous solution

Back 8

side chains

Front 9

Hydrogen bonds will form between what? (3)

Back 9

1. between atoms of two peptide bonds
2. peptide bond atoms and R groups
3. R groups

Front 10

the protein's shape is also called what?

Back 10

conformation

Front 11

the conformation of proteins is determined by what?

Back 11

sequence of amino acids

Front 12

proteins generally fold into the conformation which has the lowest _____ possible.

Back 12

free energy (G)

Front 13

the process of unfolding the protein with a certain treatment

Back 13

denaturation

Front 14

the process of refolding that protein into its original conformation

Back 14

renaturation

Front 15

each protein normally folds into a ____ stable conformation.

Back 15

single

Front 16

when proteins fold inproperly, they can form ___ that can damage cells and even whole tissues.

Back 16

aggregates

Front 17

a protein that can adopt a special misfolded form that is considered "infectious" as it can convert properly folded ___ into the abnormal conformation.

Back 17

prion protein

Front 18

protein folding in a living cell is generally assisted by special proteins called ___. (basicly makes the folding process more eddicient and reliable.)

Back 18

molecular chaperones

Front 19

____ are caused by rare proteins whose misfolding is infectious.

Back 19

Prion diseases

Front 20

____ tend to forced together in an aqueous, watery environment to minimze thir disruptive eddet of the hydrogen-bonded network of the surrounding water molecules

Back 20

Hydrophobic molecules

Front 21

what amino acids are hydrophobic molecules?

Back 21

the nonpolar side chains

Front 22

the ____ side chains tend to cluster in the interior of the folded protein.

Back 22

nonpolar (hydrophobic)

Front 23

the ____ side chains tend to arrange themselves near the outside of the folded protein, where they can form hydrogen bonds with water and with polar molecules

Back 23

polar

Front 24

when polar amino acids are buried within the proein, they are usually hydrogen-bonded to _____ or the the _____.

Back 24

other polar amino acids
or
to the polupeptide backbone

Front 25

what are the two regular folding patterns from H-bonding forming between N-H and C=O in the peptide backbone?

Back 25

a-helix and B-sheet

Front 26

folding pattern where the protein turns like a spiral

Back 26

a-helix

Front 27

example of type of protein in an a-helix pattern

Back 27

fibrous protein

Front 28

folding pattern where the indicidual chains are held together by H-bonds

Back 28

B-sheet

Front 29

example of type of protein in a B-sheet pattern

Back 29

globular protein

Front 30

formed by a H-bond between every 4th peptide bond (C=O to N-H)

Back 30

a-helix

Front 31

type of folding pattern that is usually in proteins that span a membrane

Back 31

a-helix

Front 32

a-helix structure that is coil around each other

Back 32

coild-coil shape

Front 33

the core of many protein has what folding pattern?

Back 33

B-sheet

Front 34

what are the two types of B-sheets?

Back 34

anti-parallel and parallel

Front 35

type of B-sheet that runs in an opposite direction of its neighbor

Back 35

anti-parallel

Front 36

type of B-sheet that runs in the same direction with longer looping sections between them and its neighbor.

Back 36

parallel

Front 37

the first type of protein pattern that was found in a-keratin

Back 37

a-helix

Front 38

the second type of protein pattern that was found in the protein fibroin

Back 38

B-sheer

Front 39

an unexceptional regular atructure that resembles a spiral staircase

Back 39

helix

Front 40

the polypeptide backbone, which is hydrophillic, is ____ to itself in the a-helix , and its is sheldes form the hydrophobic lipid environment of the membrane by its protruding nonpolar side chains.

Back 40

hydrogen-bonded

Front 41

Level of organization:
amino acid sequence of the protein

Back 41

primary structure

Front 42

Level of organization:
H-bond in the peptide chain backbone (a-helix and B-sheet)

Back 42

secondary structure

Front 43

Level of organization:
Non-covalent interactions between the R groups within the protein (full, 3D conformation)

Back 43

tertiary sturcture

Front 44

Level of organization:
interaction between two or more polypeptide chains (multiple subunits)

Back 44

quaternary structure

Front 45

a basic structural unit of a protein

Back 45

domain

Front 46

the modular unit from which many larger proteins are constructed.

Back 46

domain

Front 47

for a polpeptide that is N amino acids long, ____ different chains are possible.

Back 47

20^N

Front 48

___ domain can impart ___ functions to proteins

Back 48

different; different

Front 49

part of protein that can dold into a stable structure independently

Back 49

domain

Front 50

proteins usually have only one useful conformation becuase why?

Back 50

otherwise it would not be eddicent use of the energy abailable to the system

Front 51

___ has eliminated proteins that do not perform a specific function in the cell.

Back 51

natural selection

Front 52

___ have similarities in amino acid sequence and 3D structure

Back 52

protein families

Front 53

___ have simular functions such as breakdown proteins but do it differently

Back 53

protein families

Front 54

a region where proteins interact with one another through non-covalent bonds

Back 54

binding site

Front 55

each polypeptide chain of a large protein

Back 55

subunit

Front 56

protein made of two subunits. (can be same subunit of different subunit)

Back 56

dimer

Front 57

the same weak ____ that enable a polypeptide chian to fold into a specific conformation also allow proteins to bind to ech other to produce larger structures in the cell.

Back 57

noncovalent bonds

Front 58

a Hemoglobin contains two identical ____ and toe identical ____, symmetrically arraanged.

Back 58

two a-globin subunits; two B-globin subunits

Front 59

both subunits in a hemoglobin contain ____.

Back 59

heme group

Front 60

one protein assembly can be formed in long chains if the protein has ____

Back 60

two binding sites

Front 61

if the protein has two binding sites they link togehter are a ___ or ___

Back 61

helix or ring

Front 62

___ for example, is a long helical structure formed from many molecules of the protein actin

Back 62

action filament

Front 63

proteins where the poypeptide chain folda up into a compact shape like a ball with a irregular shape.

Back 63

globular proteins

Front 64

Enzymes are what type of protein?

Back 64

globular

Front 65

proteins that generally have a relatively simple. elongated 3D structure and are commonly reffered to as ___

Back 65

firous proteins

Front 66

proteins whose 3D structure is usually long sand rod shaped that takes up a long distance in the cell.

Back 66

fibrous proteins

Front 67

what is the sturcture of a hemoglobin?

Back 67

2 identical a-globin subunits and 2 identical B-globin subunits

Front 68

what are 2 important fibrous proteins?

Back 68

intermediate filaments or the cytoskeleton and extracellular matrix

Front 69

what are structural scaffolds inside the cell?

Back 69

intermediate filaments of the sytoskeletion

Front 70

what binds cells together to make tissues?

Back 70

ectracellular matrix

Front 71

what is secreted from cells and assemble in long fibers?

Back 71

extracellular matrix

Front 72

the most abundant of extracellular matris in animal tissue.

Back 72

collagen

Front 73

long triple helix with a glycine every third amino acid in the protein

Back 73

collagen

Front 74

unstructured polypeptides cross-linked together to give tissue an elastic characterisitic

Back 74

elastin

Front 75

these molecules enable skin and other tissues to stretch and recoil without tearing

Back 75

elastin

Front 76

___ form between adjacent -SH groups on the amino acid cystine

Back 76

disulfide bonds (S-S)

Front 77

the ___ is made in the ER as is necessary for extracellular proteins and not for sytosolic proteins

Back 77

S-S bond (disulfide bonds)

Front 78

____ can be between two cystenine amino acids of a singel protein or between two subunits making up the protein in a disulfide bond.

Back 78

cross linkages

Front 79

___ do not change the conformation of a protein, but instead act as a sort of "atomic staple" to reinforce its most favored conformation.

Back 79

disulfide bonds

Front 80

the ____ of a protein gives it a unique function

Back 80

conformation

Front 81

Protein must ___ with other molecules for its function

Back 81

interact

Front 82

the colecule that a protein can bind to

Back 82

ligand

Front 83

the part of the protein that interacts with the ligand

Back 83

binding site

Front 84

the binding between proteins always shows great ___ in the sense that each proein molecule can bind to just one or a few molecules out of the many thousands of different molecuels it encounters.

Back 84

specificity

Front 85

the ___ forms when amino acids from within the protein come together n the folding

Back 85

binding site

Front 86

____ are made in response to a foreign molcules

Back 86

antibodies (immunoglobins)

Front 87

the target of an antibody

Back 87

antigen

Front 88

each antibody binds to a particular target molecule extremely tightly, either ___ or ____.

Back 88

inactivating the targt directly
or
marking it for distruction

Front 89

antibodies are ___ shaped molecules with ____ at the upper ends on each arm of the __.

Back 89

y-shaped; 2identical binding sites; y

Front 90

the ___ on the end form the binding site of the antigen

Back 90

loops of polypeptides

Front 91

___ or ___ can generate a diversity of antigen binding sites, and therefore providing high specificity of the antibodies

Back 91

changes in amino acid sequence
or
in the length of the loops

Front 92

___ are used to fomr the lingand-binging sites in many proteins

Back 92

peptide loops

Front 93

proteins that bind to their substrates to convert them into chemically changes products

Back 93

enzymes

Front 94

___ make or break covalent bonds

Back 94

enzymes

Front 95

what can be grouped depending on their functions

Back 95

emzymes

Front 96

what emzymes combine to

Back 96

substrates

Front 97

molecules that speed up the reactions

Back 97

enzymes

Front 98

each type of enzyme is highly specific, catalyzing only a ____.

Back 98

single type of reaction

Front 99

an important enzyme that protects us from bacteria by breaking bacterial cell walls to cuase rupture

Back 99

lysozyme

Front 100

breaks a glycosidic bond in the cell wall by hydrolysis

Back 100

lysozyme

Front 101

holds the polysacchardie in a postion that allows the H2O to break the bond

Back 101

Lysozyme

Front 102

chemical structure that forms transiently in the course of a reaction and has the highest free energy of any reaction intermediate.

Back 102

transition state

Front 103

____ hold the polysaccharides in the active site until the reaction occurs

Back 103

non-covalent bonds

Front 104

special binding site on an enzymethat cradles the contours of its substrate molecule

Back 104

active site

Front 105

as soon as the polysaccharide binds to form an enzyme-substrate complex, the enzyme cuts the polysaccharide by ____.

Back 105

adding a water molecule across one of its sugar-sugar bonds

Front 106

what is the equation for enzyme performance?

Back 106

E+S -> ES -> EP -> E+P

Front 107

enzyme binds to two substrate molcules and orients them precisely to encourage a reaction to occur between them

Back 107

proper orientation

Front 108

binding of subsrtate to enzyme rearranges electrons in the substrate, creating partial negative and positive charges that favor a reation

Back 108

alter e- distribution

Front 109

enzyme strains the bound substrate molecule, forcing it toward a transition state to favor a reaction

Back 109

change shape

Front 110

occasionally the sequence of the protein is not enough for the fun ction of the protein. some proteins require a ____ to enhance the performance of the protein.

Back 110

non-protein molecule

Front 111

what a prosthetic group is required by an enzyme it is called ___

Back 111

co-enzyme

Front 112

the prosthetic groupd is usually ___ or ___.

Back 112

metal or vitamin

Front 113

prothetic groups may be ___ or ____ linked to the protein

Back 113

covalently or non-covalently

Front 114

inside the cell, nost proteins and enzymes do not work continuously or at full speed so that the cell can maintain itself ina state of ___ generating only those molecules it requires to thrive under the current conditions

Back 114

equilibrium

Front 115

at one level of regulation of enzymes, the cell controls how many molecules of each enzyme it makes by regulating the ____.

Back 115

expression of the gene that encodes that protein

Front 116

at one level of regulation of enzymes, the cell controls enzymatic activites by ____.

Back 116

confining sets of enzymes to particular subcellular compartments

Front 117

the most rapid and general process used to adjust reaction rates operates at the level of ____.

Back 117

the enzyme itself.

Front 118

the most common type of control occurs when a molecule other than a substrate binds to an enzyme at a special ragulatory site outside of the active site, altering the ____ at which the enzyme converts its substrates to products

Back 118

rate

Front 119

an enzyme acting early in a reaction pathway is inhibited by a late product of that pathway.

Back 119

feedback inhibition

Front 120

something that prevents an enzyme from acting.

Back 120

negative regulation

Front 121

where the enzyme's activity is stimulated by a regulatory molecule rather than being shut down

Back 121

positive regulation

Front 122

occurs when a product in one branch of the metabolic maze stimulates the activity of an enzyme in another pathway.

Back 122

positive regulation

Front 123

an example of ___ is hight [ADP] cause the activtion of the glycolysis pathway to make more ATP

Back 123

positive regulation

Front 124

some of the proteins have two binding sites which can communitcate: ___ for substrate binding and a ___ for binding of a regulatory molecule

Back 124

active site; second site

Front 125

a protein that exsits in two or more conformations depending on the binding of a molecule at a site other than the atalytic site.

Back 125

allosteric proteins

Front 126

proteins that are composed of multiple subunits often display a copperative response to ligand binding

Back 126

allosteric proteins

Front 127

because each protein conformation will have somewhat different contours on its surface, the protein's binding site for ligans will be altered when the protein ___.

Back 127

changes shape

Front 128

protein that regulate using allostery, undergoes a conformational change which is called ___.

Back 128

allosteric transition

Front 129

some proteins are regulated by the addition of a ___ .

Back 129

PO4 group

Front 130

negative charges on PO4 can attract positively charged side chains, causing ___.

Back 130

conformation change

Front 131

reversible ___ regulate many eukaryotic cell funstion by turning things on and off

Back 131

protein phosphorylations

Front 132

Protein ___ ass the PO4 in phosphorylation

Back 132

Kinases

Front 133

the protein ___ remove PO4 group in phosphorylation

Back 133

phosphatase

Front 134

the protein __ is capable of putting the PO4 on 3 different amino acids residues during phosphorylation

Back 134

kinases

Front 135

what are the three amino acids that Kinases can put Po4?

Back 135

Serine
Theronine
tyrosine

Front 136

y can kinases put a PO4 group on serine, theronine, and tyrosine?

Back 136

because they have a -OH group on their R group

Front 137

protein that removes the PO4 group that may be specific for 1 or 2 reactions or may be non-specific

Back 137

phosphatases

Front 138

the removal of a PO4 group is called what?

Back 138

dephosphorylation

Front 139

an allosteric protein whose conformation is determined by its association with either GTP or GDP. includes many proteins involved in cell signaling

Back 139

GTP-binding proteins

Front 140

instead of transferring PO4 from ATP, ___ binds tightly to the protein and make protein active

Back 140

GTP

Front 141

the GTP-binding protein hydrolyzes GTP to GDP - releasing a phophate - and flips to an ____ conformation.

Back 141

inactive

Front 142

___ conformation that is regained by dissociation of the GDP, followed by the binding of a fresh molecule of GTP

Back 142

active

Front 143

proteins can move in the cell, but with bery little uniformity

Back 143

motor proteins

Front 144

protein that uses energy derived from ATP hysrolysis to propel itself along a protein filament or polymetric molecule.

Back 144

motor protein

Front 145

complexes of 10 or more proteins that work together

Back 145

protein machines

Front 146

consider the drawing of the feedback inhibition. what will happen if, instead or the indicated feedback, feedback inhibition from Z affects the step B -> C only?
discuss how useful these regulatory schemes would be for the cell.

Back 146

a)feedback inhibition from Z that affectts the reaction B->C would increase the flux through the B -> X -> Y -> Z pathway, because the conversion of B to C is inhibited. Thus, the more Z there is, the more production of Z would be stimulated. This is likely to result in an uncontrolled "runaway" amplification of this pathway.

Front 147

consided the frawing of the feedback inhibition. What will happen if, instead of the indicated feedback, feedback inhibition from Z affects the step Y -> Z only?

Back 147

feedback inihibition from Z affecting Y->Z controls the production of Z, in this scheme, however, X and Y are still made at mormal rates, even though both of these intermediates are no longer neeeded at this lvevl. this pathway is therfore less efficeint than the one shown in the drawing.

Front 148

consider the drawing of the feedback inhibition. what will happen if, instead of the indicated feedback, Z is a positive regulator of the step B->X?

Back 148

if Z is a positive regulator of the step B->X, then the more Z there is, the more B will be converted to X and therefore shunted into the pathway producing more Z. this would result in a runaway amplicication.

Front 149

consider the drawing of the feedback inhibition. what will happen if, instead of the indicated feedback, Z is a positive regulator of the step B->C?

Back 149

if Z is a positice regulator of the step B->C, then accumulation of Z leads to a redirection of the pathway to make more C. this is a second passible way, in addition to that shown in the drawing, to balance the distribution of compounds into the two branches of the pathway.

Front 150

only a few amino acid side chains contribute to the ___. the rest of the protein is required to maintain the polypeptide chain in hte correct position, provide additional binding sites for requlatory purposes, and localize the protein in the cell.

Back 150

active site.

Front 151

Some enzymes form ___ intermediates with their substtrates; however in all cases the enzyme is restored to its original structure after the reaction

Back 151

covalent

Front 152

___ can contain any number of strands becuase the two strands that form the rims of it are available for hydrogen-bonding to other strands

Back 152

B-sheets

Front 153

the specificity for an antibody molecule is contained in loops on its surface. these loops are contributed by what two domains?

Back 153

light-chain domains and heavy-chain domains

Front 154

the possible linear arrangements of amino acids tha lead to a stably folded protein domain are so few that most new proteins elvolve by ___.

Back 154

alteration of old ones.

Front 155

enzymes that generally bind one or more molecules that function as regulators at sites that are distinct from the active site

Back 155

allosteric

Front 156

___ are a major contributer to the 3-D structure of macromolecules

Back 156

noncovalent bonds

Front 157

separates specific macromolecules because of thei interactions with specific ligands, not beacule of their charge.

Back 157

affinity chromatography

Front 158

the __ an organelle is, the more centrifugal force is experiences and the faster it sediments, sespite an increased frictional resistance from the fluid through which it moves.

Back 158

larger

Front 159

consider the following protein sequence as an a-helix:
Leu-lys-arg-ile-val-asp-ile-leu-ser-arg-leu-phe-lys-val
How many turns does this helix have?

Back 159

as it takes 3.6 amino acid residues to complete a turn of an a-helix, this sequence of 14 amino acids would make close to 4 full turns.

Front 160

consider the following protein sequence as an a-helix:
Leu-lys-arg-ile-val-asp-ile-leu-ser-arg-leu-phe-lys-val
Do you find anything remarkable about the arrangement of the amino acids in this sequence when folded into an a-helix?

Back 160

it is remarkable because its polar and hydrophobic amino acids are spaced so that all polar resudes are on one side of an a-helix and all the hydrophbic residues are on the other. it is therefore likely that such an amphiphathic a-helix is exposed on the proteins surface with its hyfrophobic side facing the protein;s interior. in addition, two such helices might wrap around each other.

Front 161

simple enzyme reactions often conform to the equation
E+S <-> ES -> EP <-> E+P
where E, S, and P are enzymes, substrate, and product, respectively. What does ES represent in this equation?

Back 161

ES represents the enzyme-substrate complex

Front 162

simple enzyme reactions often conform to the equation
E+S <-> ES -> EP <-> E+P
where E, S, and P are enzymes, substrate, and product, respectively. why is the first step shown in with bidirectional arrows and the second step as a unidirectional arrow?

Back 162

Enzyme and substrate are in equilibrium between their free and bound states; once bound to the enzyme, a substrate molecule may either dissociate again or be converted to product. as substrate is converted to product, however, a reaction often proceeds strongly in the forward direction, as indicated by the unidirectional arrows.

Front 163

simple enzyme reactions often conform to the equation
E+S <-> ES -> EP <-> E+P
where E, S, and P are enzymes, substrate, and product, respectively. why does E appear at both ends of the equation?

Back 163

the enzyme is a catalyst and is therefore liberated in an unchanges form after the reaction; thus, E appears at both ends of the equation.

Front 164

simple enzyme reactions often conform to the equation
E+S <-> ES -> EP <-> E+P
where E, S, and P are enzymes, substrate, and product, respectively. one often finds that high concentrations of P inhibit the enzyme. Suggest why this might occur.

Back 164

often the products of a reaction resemble the substrates sufficiently that they can also bind to the enzyme. any enzyme molecules that are bound to product are unavailable for catalysis; ecess P therefore inhibits the reaction by lowering the concentration of free E.

Front 165

simple enzyme reactions often conform to the equation
E+S <-> ES -> EP <-> E+P
where E, S, and P are enzymes, substrate, and product, respectively. compound X resembles S and binds to the active site of the enzyme but cannot undergo the reaction catalyzed by it. what effects would you expect the addition of X to the reaction to have? Compare the effects of X and or accumulation of P.

Back 165

compound X is an inhibitor of the reaction and workd similarly by forming an EX complex. However, since P has to be made before it can inhibit the reaction, it takes longer to act than X, which is present from the beginning of the reaction.

Front 166

comprised of genes

Back 166

DNA

Front 167

form during cell division

Back 167

chromosomes

Front 168

DNA

Back 168

doexyrobonucleic acid

Front 169

the process through which the information encoded in DNA is interpreted by the cell to guide the synthesis of proteins

Back 169

gene ecpression

Front 170

threadlike structures in the nuleus of the eucayotic cell that becomes visible as the cell begins to divide

Back 170

chromosomes

Front 171

long polunucleotide chains that make up DNA molecule

Back 171

DNA chains or DNA stands

Front 172

the two chains in a DNA molcule are held together by what?

Back 172

hydrogen bonds

Front 173

composed of a five-crabon sugar to which are attached one or more phosphate groups and a nitrogen-containing base

Back 173

nucleotide

Front 174

monomer are celled ____.

Back 174

nucleotides

Front 175

base is nucleotide are what?

Back 175

purine or pyrimidine

Front 176

purine bases are what amino acids?

Back 176

adenine and guanine

Front 177

pyrimidine bases are what amino acids?

Back 177

thymine, cytosine, and uracil

Front 178

sugar in nucleotide is what?

Back 178

deoxyribose or ribose

Front 179

Base and sugar have what type of bond?

Back 179

glycosidic bond

Front 180

sugar and phosphate have what type of bond?

Back 180

phosphodiester bond

Front 181

what is the backbone of DNA

Back 181

sugar-phosphate-sugar-phosphate

Front 182

what letters are used to denote the nucleotides in DNA

Back 182

ATGC

Front 183

how is the polarity of a DNA chain indicated?

Back 183

one end is called 3' and the other end is 5'

Front 184

all the bases are on the ___ of the helix and the sugar-phosphate backbones are on the ___ of the helix.

Back 184

inside; outside

Front 185

the two strands in DNA are ___ which means they run in opposite directions

Back 185

anti-parallel

Front 186

the sequence of nucleotides within a portion of DNA

Back 186

gene

Front 187

sum of all genes

Back 187

genome

Front 188

in a DNA double helix, how many bases per helical turn are there?

Back 188

10

Front 189

human have __ pairs of chromosomes

Back 189

23

Front 190

in a pair of chromosomes: one from ___ and other from __.

Back 190

mother; father

Front 191

_ pairs are always homologous chromosomes

Back 191

22 pairs

Front 192

what chromosome is male is always non-homologous

Back 192

sex chromosome

Front 193

what are female sex chromosomes and what are male sex chromosomes?

Back 193

females: (X,X)
males: (X,Y)

Front 194

the complex of DNA and protein are called ___

Back 194

chromtin

Front 195

each chromosome consists of what two things?

Back 195

DNA molecule with proteins

Front 196

chromosomes are also associated with other proteins involves in what three things?

Back 196

gene expression, DNA replication, and DNA repair

Front 197

a display of the full set of 46 human chromosomes is call the human ___.

Back 197

karyotype

Front 198

allows us to look for genetic abnormalities and alterations caused by cancer or gentic disorder

Back 198

karyotype

Front 199

the chromosomal differences is shaped by __ and unique ___.

Back 199

history and genentic events

Front 200

in the cell cycle where chromosomes are duplicated

Back 200

interphase

Front 201

in the cell cycle where chromosomes are distributed to the two daughter nuclei

Back 201

mitosis (M phase)

Front 202

the orderly sequence of events a cell takes to duplicate its contents and dicides into two

Back 202

cell cycle

Front 203

during interphase the ___ are extended as long, thin, tangles threads of DNA in hte nucleus.

Back 203

chromosomes

Front 204

the chromosomes in the interphase are refered as

Back 204

interphase chromosomes

Front 205

the location at which duplication of the DNA begins

Back 205

replication origin

Front 206

alloes the DNA to open so that the DNA replication machinery can get in and do DNA synthesis

Back 206

replication origin

Front 207

allows for the DNA replication machinery access to the entire genomic sequence without loosing important information

Back 207

telomere

Front 208

contain repeated nucleotide sequences that enable the ends of chromosomes to be replicated.

Back 208

telomere

Front 209

protect the end of the chromosome from being mistaken by the cell as a broken DNA molcule in need of repair

Back 209

telomere

Front 210

the DNA coild up, adopting a more and more compact sturcture until the hightly condesed ____ have been formed

Back 210

mitotic chromosomes

Front 211

allows microtubules to attach and sparate the chromosomes to the new daughter cells

Back 211

centromere

Front 212

the chromosome must have several structures that are necessary to replicate and divide the DNA. what are they?

Back 212

replication origin
telomere
centromere

Front 213

nucelar membrane is supported by two networks of protein filaments. what are they?

Back 213

nuclear lamina and intermediate filaments

Front 214

forms a thin layer underlying and supporting the inner nuclear membrane; while the other, less reqularly organized, surrounds the outer nuclear membrane.

Back 214

nuclear lamina

Front 215

chromosomes occupy __ arear to keep from tangling (may be held in place by attachment to the nuclear membrane or lamina)

Back 215

specific

Front 216

____ contains the chromosomes carrying genes for rRNA

Back 216

nucleolus

Front 217

a complex of proteins and DNA that is very dispersed

Back 217

chromatin

Front 218

the compact form of DNA so that it is protected during mitosis

Back 218

chromosomes

Front 219

structural unit of chromatin which gives "bead-on-a-string" look

Back 219

nucleosomes

Front 220

in a chromatin sturctural unit, the ___ is the the DNA and the bead is the ___ that the DNA is wrapped around. the protein is ___.

Back 220

string; nucleosome core particule; histone

Front 221

nucleosome core plus linker DNA

Back 221

nuclesomes

Front 222

histone is a octamer with 2 copies or what? (4)

Back 222

H2A, H2B, H3, and H4

Front 223

proteins with a large proportion of positively charged amino acids helps to ___.

Back 223

bind the negatively charged DNA

Front 224

what are the 2 main groups of a histone?

Back 224

nucleosomal histones and H1 histones

Front 225

each nucleosome core particule is separated from the next by a region of ___.

Back 225

linker DNA

Front 226

what histones are highly conserved?

Back 226

H3 and H4

Front 227

what histones are larger and less conserved?

Back 227

H1

Front 228

what is the packed chromatin model also called?

Back 228

zigzag model

Front 229

while not as condensed as mitotic chrmosomes, ther are areas more tightly packed than others.

Back 229

interphase chromosomes

Front 230

most highly condensed chromatin is called ____.

Back 230

heterochromatin

Front 231

genes that aren't being ecpressed in interphase chromosomes

Back 231

heterochromatin

Front 232

the more extended chromatin is calle ___.

Back 232

euchromatin

Front 233

chromatin that is either being transcribed or easlly avaliable for transcription

Back 233

euchromatin

Front 234

in a ____, one of the X chromosomes in a female sex chromosome becomes inactive and highly condensed.

Back 234

barr body

Front 235

some cells have the paternal X off and some have the maternal X off. this happens during ___ and once off, all cells that arise from that cell will have it off.

Back 235

early development

Front 236

when a X chromosome is permanently turned off it us then passed down or ____ in all the cells that arise from that cell.

Back 236

inherited

Front 237

change the structure of nucleosomes using energy from ATP hydrolysis

Back 237

chromatin remodeling complexes

Front 238

unwind DNA to allow access for DNA replication, repair, and gene expression

Back 238

chromatin remodeling complexes

Front 239

allows for turning on and off genes using "histome codes"

Back 239

reversible modifiction of histone N-terminal tails

Front 240

the ___ of a DNA strand commonly refers to the orientation of its sugar=phosphate backbone

Back 240

polarity

Front 241

G-C base pairs are held together by ___ hydrogen bonds, whereas A-T base pairs are held together by ___ hydrogen bonds

Back 241

three; two

Front 242

how many possible nucleotides sequences are there for a stretch of DNA that is N nucleotides long, it it is (a) single-stranded or (b) double-stranded

Back 242

a single-stranded DNA molecule that is N nucleotides long con have any one of 4^N possible sequences, but the number of possivle double stranded DNA molecules is more difficult to calculate. Many of the 4^N single-stranded sequences will be the complement of another possible sequence in the list. If N is an odd number, then every single-srtanded sequence will complement another sequence in the list so the the number of double-stranded sequences will be 0.5x4^N. if N is an even number, then there will be slightly more than this since some sequences will be self-complementary and then actual value can be calculated to be 0.5x4^N + 0.5x4^N/2.

Front 243

suppose you had a method of cutting DNA ar specidic sequence of nucleotides. How many nucleotides lond would such a sequence have to be in order to make just one cut in a bacterial genome of 3x10^9 nucleotide pairs?

Back 243

to specify a unique sequence which is N nucleotides long, 4^N has to be larger than 3x10^6. thus, 4^N > 3x10^6 solved for N, give N/>ln (3x10^6)/ln(4).

Front 244

the two strand of DNA double helix can be separated by heating. How would you determine the rate at which it would melt?

Back 244

A-T group have 2 hydrogen bonds and C-G groups have 3. so Add up all the hydrogen bonds and compare to other strands. the one with the lowest number of hydrogen bonds will melt the fastest and the ones with the highest will melt the slowest.

Front 245

each eucaryotic chromosome must contain what DNA sequence elements? (3)

Back 245

mulitple orginins of repliction, two telomeres, and one centromere

Front 246

Nucleosome core proteins are approximately how long?

Back 246

11 nm in. diameter

Front 247

nucleosomes core proteins are packed to form how long of a filament?

Back 247

30 nm in. diameter

Front 248

duplication of DNA must happen prior to ___

Back 248

cell division

Front 249

cells monitor the DNA to repair any damage to minimize the ____

Back 249

detrimental mutations

Front 250

permanent accidental changes that may affect the genetic information but could also benifit the orgamism

Back 250

mutation

Front 251

each strand of parent DNA is used as a ___ to make the new daughter strand

Back 251

template

Front 252

DNA replication makes ____

Back 252

2 new complete double helices

Front 253

beacuse each parental strand seves as the tmeplate for one new strand, each of the daughter DNA double helices ends up with one of the original strands plus one strand that is completely new; this style of replication is said to be ___

Back 253

semiconservative

Front 254

the position at which the DNA is first opened to start DNA snthesis is ____

Back 254

replication origins

Front 255

___ rich stretches of DNA are typically found at replication origins

Back 255

A-T

Front 256

How many replication origins are there in human genome?

Back 256

1,000s

Front 257

strands are separated to allow replication machinery contact with the DNA at ___.

Back 257

replication origin

Front 258

once an initiator protein ind to DNA at the replication origin and locally opens up the double helix, it attracts a group of proteins that carry out DNA replication operatings as a _____.

Back 258

protein machine

Front 259

y-shaped region of replicating DNA where the two daughter strands are formed

Back 259

replication fork

Front 260

the replication machine is mobing along the DNA, opening up the two strands of the double helix and using each strand as a template to make a new daughter strand.

Back 260

replication forks

Front 261

two replication ofrks are formed starting from each replicationn origin, and they move away from the origin in both direction, unzipping the DNA as they go. Therefore DNA replication is termed _____

Back 261

Bidirectional

Front 262

at the heart of the replication machine is an enzyme called ____

Back 262

DNA polymerase

Front 263

the bidirectional movement of the DNA relication machiner at each end of the replication fork is where DNA ____ occurs

Back 263

synthesis

Front 264

catalyzes the addition of nucleotide to the growing DNA chain as a nucleoside triphosphate

Back 264

DNA polmerase