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Biology 224 > EXAM 4 - Chapter 14, Mitosis > Flashcards

EXAM 4 - Chapter 14, Mitosis Flashcards

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1
Q

Chromatin consists of…

A

DNA and proteins

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2
Q

DNA is…

A

one complete, double stranded DNA molecule (in an unduplicated chromosome

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3
Q

There are both _______ and _____ proteins

A

histone, nonhistone

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4
Q

Nucleosome cores consist of

A

2 copies of each of 4 different histone proteins

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5
Q

Histone H1….

A

connects DNA to the Nucleosome core and connects adjacent cores together

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6
Q

Nonhistone proteins…(2)

A

more varied but less numerous

thought to control individual genes by binding or dissociating from DNA (think transcription factors

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7
Q

Chromosomes consist of

A

1 chromatid (unduplicated)
2 chromatids (duplicated)

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8
Q

Sister chromatids are

A

genetically identical, one is used as template to make the other

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9
Q

Centromere is

A

visible as a constricted region, represents area to which microtubules attach during cell division

There is DNA under the protein (kineticore proteins)

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10
Q

In diploid organisms…

A

chromosomes are inherited in sets, one set from each parents

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11
Q

There are two copies of…

A

each chromosome, one inherited from each parent

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12
Q

Homologues, or Homologous chromosomes are

A

the two copies of each chromosome

two duplicated chromosomes making a pair of chromosomes

different info, but same kind of info in homologous pairs

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13
Q

Haploid organisms..

A

contain a single copy of each chromosome

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14
Q

In diploid organisms, the only cells that are haploid are…

A

the gametes, sex cells, there is only one member of each pair

one one set of chromosomes

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15
Q

Cells grow through a

A

regular cycle of growth and then division called the cell cycle

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16
Q

Cells…then…

A

grow to about double their size, replicate their DNA to produce two copies (interphase)

then divide, which includes splitting of the cytoplasm (cytokinesis) and splitting of DNA (mitosis) equally between the two daughter cells

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17
Q

So cell division includes…

A

mitosis and cytokinesis

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18
Q

Division of _____ and _____ are separate/different

A

nucleus and cytoplasm

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19
Q

Interphase consists of…

A

3 separate phases which are G1, S, G2

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20
Q

During G1

A

proteins synthesis and growth predominate, organelles replicate and cell size doubles

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21
Q

During S

A

DNA replicates to build a second (sister) chromatid using the original as a copy

DNA replicated

One chromatid becomes 2 sister chromatidsD

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22
Q

During G2

A

Protein synthesis again predominates producing materials needed for division (tubulin for microtubules, etc)

Size already has increased to max, this stage is more like maturing and developing

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23
Q

Mitosis…

A

called nuclear division

Distributes exact copies of genetic information to the daughter cells

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24
Q

The 4 phases of mitosis are

A

prophase
metaphase
anaphase
telophase

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25
Q

Prophase characterized by…(5)

A
  • condensation of each chromosome (duplicated)
  • disappearance of the nucleolus
  • centrosomes (pair of centriols) separate and move to opposite nuclear poles (these were replicated during G1 and this movement establishes the polarity of cell)
  • Disentigration of the nuclear membrane into vesicles
  • Spindle fibers attach to chromosome
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26
Q

_____________ marks the beginning of prophase

A

condensation of chromosomes

27
Q

Centrosomes also known as

A

Microtubule organizing regions

28
Q

Centrosomes…

A

control growth of microtubules

29
Q

Polar microtubules..

A

run from pole to pole

30
Q

Kinetochore Microtubules…

A

run from centrosome to centromere (middle of chromosome)

31
Q

Metaphase is characterized by…

A

spindle fibers moving chromosomes to metaphase plate (equator of cell)

most distinct phase, everyone lined up, more condensed

32
Q

Anaphase is characterized by…

A

separation of chromatids and movement to opposite poles

right when they start to separate = anaphase

33
Q

Two important components of anaphase are….and they…

A

separate - degrades proteins holding sister chromatids together

cytoplasmic dynein - walks chromosomes along microtubules (walk along pathways to carry chromosomes apart)

34
Q

Telophase is characterized by…

A

Reversal of prophase with decondensation of chromosomes and reformation of nuclear membrane and nucleolus, breakdown of miotic spindle

Cytokinesis happening simultaneously

Now have almost two nucleoses,

35
Q

Cytokinesis… (2)

A
  • is the division of the cytoplasm
  • accomplished using the combined action of at least 20 different proteins
36
Q

__________ plus _________ divides the entire cell into two daughter cells

A

mitosis (division of the nucleus) plus cytokinesis (division of the cytoplasm)

37
Q

In animal cells, cytokinesis…

A

is accomplished by construction of a band of microfilaments of actin and myosin (CLEAVAGE FURROW))

38
Q

In plant cells…

A

vesicles are pulled down microtubule highways by kinesin motors and they fuse to form new plasma membrane/cell wall (CELL PLATE FORMATION)

39
Q

Result of mitosis (3)

A
  • ploidy of cells formed = same as mother cell, DIPLOID
  • Number of cells formed = 2
  • Genetic makeup of cells formed = genetic clones
40
Q

_______________ control the mitosis cell cycle

A

two groups of proteins

41
Q

______________ are proteins which are activated by binding to ________

A

Cyclin-dependent kinases (Cdk) activated by binding to cyclin

42
Q

Cdks are…but cyclins are…

A

Cdks produced THROUGHOUT THE CYCLE

Cyclins produced AS NEED THEN DESTROYED during particular stages in the cycle

43
Q

So the cell cycle is regulated by

A

a cascade of protein kinase activities

44
Q

And the signal is…

A

amplified in strength by this cascade activity in cell signaling

45
Q

It is an example of ________ when both protein work together

A

cell signaling

46
Q

Initially only ___ is present in G1

A

Cdk , NO G1 CYCLINS have been produced

47
Q

Passage through G1 (general):

A

if growth conditions are favorable, G1 cyclins are produced that bind to and activate Cdks

48
Q

Then active Cdk…

A

phosphorylates the protein RB, thereby inactivating it

Initially, active RB blocks entry through the restriction point

49
Q

Restriction points are

A

places where certain biochemical activities must take place to get past the restriction

50
Q

During G1 SPECIFIC:

A

Cdk4 activated by cyclin D, Cdk2 activated by Cyclin E (D and E = G1 cyclins)

and once again activated Cdks phosphorylate and inactivate RB, which allows cell to pass restriction point and enter S phase

51
Q

Active/blocking RB normally…but when phosphorylated…

A

normally bound to E2F, a regulatory transcription factor

when RB is phosphorylated, it releases E2F which then binds to genes, promoting the transcription of proteins that promote cell division (and passage through RB)

52
Q

Once cell gets through G1 site…

A

this is the most important site and it has committed to cell division

53
Q

RB is the…

A

inhibitor

54
Q

Once RB (the inhibitor) is inhibited…

A

the cell can pass through G1 and proceed into S

55
Q

After this…

A

G1 cyclins are then degraded

56
Q

G1 cyclins are…

A

not active from the S phase of the remaining cycle onward, DO NOT become active until G1 phase of NEXT cycle

57
Q

During the S phase…

A

Cyclin A is produced, it activates Cdk2 which stimulates DNA replicated

no restriction site here

58
Q

Passage through G2:

A

after DNA is fully replicated, Cyclin B is produced to activate cdk1 for entry into motosis

this allows cell to pass G2 restriction site

59
Q

So, in summary…

A
  • different cyclins produced at different stages of the cell cycle

they activate different cdks which begin an enzyme cascade to activate passage through different portions of interphase

60
Q

CDKs therefore…

A

control the passage of cells through the cell cycle

61
Q

some cells have the G1 restriction site…

A

pressed down, so that they will never be able to get passed and cells cannot replicated

G1 restriction site called molecular break

62
Q

Cells do not want o

A

prematurely advance through the cell cycle

63
Q

For example…

A

radiation damage stimulates production of p21

p21 binds to G1-cdks preventing cyclin from binding and activating them before the DNA damage can be repaired, so once repaired they can move on

This prevents that cell from making more damaged cells

Biology 224 (18 decks)

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