Module 1—The Cell Cycle Flashcards

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1
Q

prokaryotic DNA vs eukaryotic DNA

A

ProkaryotesEukaryotes

  • not bound to protein
  • circular
  • usually no introns
  • bound to proteins
  • linear
  • introns
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2
Q

prokaryotic organelles vs eukaryotic organelles

A

ProkaryotesEukaryotes

  • no membrane-bound organelles
  • no nucleus
  • 70S ribosomes
  • membrane-bound
  • nucleus
  • 80S ribosomes
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3
Q

prokaryotic reproduction vs eukaryotic reproduction

A

ProkaryotesEukaryotes

  • binary fission
  • single haploid chromosome
  • mitosis
  • meiosis
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4
Q

prokaryotic size vs eukaryotic size

A

ProkaryotesEukaryotes
* 1-5 μm

  • 10-100 μm
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5
Q

3 functions of cell division

A
  • Reproduction
  • Growth & development
  • Repair & renewal
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6
Q

division produces ______ growth in cell number

A

exponential

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7
Q

phase in which most adult cells live

A

G0 or prolonged G1

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8
Q

cell cycle

A

life of a cell from formation to its own division

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9
Q

DNA is composed of 2 ___________ strands around an imaginary axis, forming a _________

A

polynucleotide

double helix

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10
Q

direction of polynucleotide strands

A

antiparallel to one another

5’ and 3’ ends of each

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11
Q

base pairs are situated _______ to helix axis

A

orthogonally

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12
Q

genome

A

all DNA in a cell

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13
Q

responsible for production of gametes

A

germline cells

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14
Q

“spools” for DNA

A

histones

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15
Q

DNA wrapped around one histone

A

nucleosome

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16
Q

octamer

A

8 core histones forming a spool

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17
Q

____ base pairs in a nucleosome

___ base pairs not around a histone

A

150

20

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18
Q

octamer includes 2 copies of 4 types of histones:

A

H2A

H2B

H3

H4

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19
Q

function of H1 histones

A

guide and organize nucleosomes

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20
Q

what do histone tails interact with?

what do they determine?

how is this significant?

A

nonhistone proteins and other octamers

density of the “wrapping” of the nucleosome

density determines whether genes are “on” or “off”

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21
Q

proteins involved with condensed nucleosomes

A

condensins

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22
Q

how is DNA condensed during mitosis?

A

bound into higher order loops by intense cross-linking

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23
Q

basic structure of chromatin

A

collection of nucleosomes = 30nm fibers

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24
Q

DNA is replicated in ___ phase, in the _______ state

A

S

chromatin

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25
Q

after copying of DNA, the ________ are formed from the original chromosome and its copy

A

sister chromatids

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26
Q

how are sister chromatids jointed?

A

cohesins join them all along their length

they are joined at the centromere most closely

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27
Q

constituents of centromere

A

repetitive sequences in DNA, mediated by proteins which recognize and bind to centromeric DNA

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28
Q

phases of the cell cycle

A
  • Interphase
    • G1
    • S
    • G2
  • Mitotic phase
    • Prophase
    • Prometaphase
    • Metaphse
    • Anaphase
    • Telophase
    • Cytokinesis
29
Q

events of G1

A

↑ metabolism, organelles, resources

30
Q

events of S phase

A

growth & duplication of chromosomes

31
Q

most dangerous phase for cell

why?

A

S phase

proteins cannot be synthesized from DNA undergoing replication

32
Q

events of G2

A

growth & more duplication

centrosome duplicates (each has 2 centrioles)

↑ proteins necessary for mitosis

33
Q

part of spindle that isn’t really necessary, and not found in plants

A

centrioles

34
Q

events of prophase (5)

A

chromatids condense into chromosomes, with sister chromatids adhering to one another

nucleoli disappear

early mitotic spindle forms from centrosomes

aster is present

centrosomes move apart, pushed by lengthening microtubules

35
Q

events of prometaphase (5)

A

begins with centrosomes on opposite poles, beginning to elongate cell

nuclear envelope fragments

kinetochore proteins forms on the centromeric DNA of each chromatid

mitotic spindle attaches to sister chromatids at kinetochore and begins to pull them back and forth

nonkinetochore tubules interact with those from the opposite pole, lengthening the cell

36
Q

events of metaphase (2)

it is the beginning of…

A

chromosomes align on metaphase plate on cell equator

tension on chromatids is equal in both directions

beginning of the end of mitosis

37
Q

events of anaphase (5)

A

Anaphase Promoting Complex (APC/C) frees separase from securin proteins

cohesin proteins are cleaved by separase

2 liberated daughter chromosomes are pulled apart toward opposite poles

nonkinetochore tubules push against one another

kinetochore tubules are depolymerized in order to shorten

38
Q

functions of APC/C

A

frees separase from securin

degrades cyclins

39
Q

events of telophase (3)

A

nucleoli reform

nuclear envelopes reform

remaining microtubules are depolymerized

40
Q

events of cytokinesis (animals and plants)

A

Cleavage furrow is “pinched” by contractile ring of actin and myosin filaments

In plant cells, a cell plate forms - small cell wall fragments by vesicles

41
Q

function of separase

A

cleaves cohesins, liberating sister chromatids from one another

42
Q

function of securin

A

holds separase when not in use

43
Q

constituents of contractile ring

A

actin and myosin

44
Q

function of mitotic spindle

A

controls movement of chromosomes

45
Q

spindle polymerizes from…

A

components of cytoskeleton

tubulin proteins

46
Q

radial array of very short microtubules - contact plasma membrane, pointing away from equator

A

aster

47
Q

kinetochores

A

protein complexes associated with centromeres

point of attachment for microtubules

48
Q

ensures cell safely completes cycle

A

checkpoints

49
Q

importance of G1 checkpoint

A

“restriction or start” point, major decision in the cell’s life

determines if cell will go on to S phase

if it goes on and fails, it will initiate apoptosis

50
Q

importance of G2 checkpoint

A

ensures there is enough mitotic cyclin for mitosis to be completed

51
Q

importance of mitotic checkpoint

when is it completed?

A

ensures equal separation of chromosomes

occurs after attachment of all kinetochore microtubules with equal tension on metaphase plate

52
Q

is cyclin or CDK retained and reused?

which one has a variable concentration?

which one is degraded

A

CDKs retained

cyclins variable concentration

cyclins degraded

53
Q

Cyclin D + Cdk4 + Cdk6

A

regulate movement from G1 to S phase

54
Q

regulate S phase and G2 phase

A

Cyclin E + cyclin A + Cdk2

55
Q

Cyclin B + cyclin A + Cdk1

A

mitotic complexes

56
Q

triggers cell’s passage past G2 checkpoint into M phase

A

maturation-promoting factor

57
Q

MPF’s negative feedback system

A

switches itself off by triggering the degradation of its cyclin component at the APC/C

58
Q

molecular function of CDK complexes

A

phosphorylate other proteins in the cell, initiating kinase cascades which mediate the events of the cell cycle

59
Q

released by other cells and stimulate division

A

growth factors

60
Q

made by platelets, facilitating division of fibroblasts

A

platelet-derived growth factor

61
Q

define density-dependent inhibition

A

division is inhibited when optimum cell density is reached in the immediate vicinity

62
Q

define anchorage dependence

A

to divide, cells must be attached to substratum

63
Q

3 steps of binary fission

A

increases in size, doubles its DNA, and splits

64
Q

in binary fission, the DNA replicates at the…

A

point of origin

65
Q

ensures DNA separates correctly during binary fission

A

tethering of DNA to each side of the cell by proteins

66
Q

mitotic differences in diatoms & yeasts

A

nuclear envelope does not break down

67
Q

mitotic differences in dinoflagellates

A

partial breakdown of the nuclear envelope to allow microtubules through

68
Q

transformation

A

cell becomes able to divide indefinitely