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Flashcards in The Cell Cycle Deck (33):
1

What occurs during the M phase?

the nucleus and cytoplasm divide (mitosis and cytokinesis)

2

What occurs during interphase?

it is the period between cell divisions (G1 phase, S phase, G2 phase)

3

nuclear division = ?
cytoplasmic division = ?

mitosis
cytokinesis

4

True or false:
As mature cells become specialized, they always continue to divide.

false; they lose the ability to divide

5

What phase are cells in when they do not divide?

G0: resting, cell cycle exit

6

What happens at G1, S and G2 phase?

G1: cellular contents other than chromosomes are duplicated
S: chromosomes are duplicated
G2: checks for errors

7

What is the function of the cell cycle control system?

delays later events until the earlier events are complete

8

What are the three major checkpoints?

1. start checkpoint (enter cell cycle and proceed to S phase)
2. G2/M checkpoint (enter mitosis)
3. metaphase to anaphase checkpoint (trigger anaphase and proceed to cytokinesis)

9

What are the five stages of mitosis?

prophase, prometaphase, metaphase, anaphase, telophase

10

During prophase, replicated chromosomes condense into...

condensin protein complexes

11

Mitotic spindle assembly consists of:
-centrosome ______
-bipolar ______

duplication
microtubules

12

What happens at the end of G2?

replicated chromosomes are dispersed and tangled

13

At the beginning of mitosis, chromosomes condense into _______

condensin

14

Where are minus ends of microtubules stabilized?

MTOC

15

What occurs during prophase? (start of M phase)

bipolar mitotic spindle assembly starts; requires disassembly and reassembly of microtubules

16

The centrosome MTOC consists of a pair of...

centrioles organized at right angles to each other

17

What is a centriole composed of?

9 fibrils of 3 microtubules each

18

What kind of ring complexes surround the centrosome structure?

gamma-tubulin ring complexes

19

What is a gamma-TuRC?

a complex of proteins that form a ring structure

20

The gamma-tubulin binds to the ring structure and acts as...

an attachment site for alpha and beta tubulin dimers

21

What does a gamma-TuRC form at the microtubule minus end?

a stabilizing cap

22

Where does nuclear envelope breakdown occur?

occurs at the boundary between prophase and prometaphase

23

What is the nuclear lamina?

meshwork of interconnected nuclear lamin proteins

24

What is lamin?

a special class of intermediate filaments that form a 2D lattice on the inner nuclear membrane

25

What triggers nuclear envelope breakdown?

phosphorylation of lamins

26

Which stage consists of the completion of mitotic spindle assembly?

prometaphase

27

During prometaphase, what do the chromosomes attach to?

spindle microtubules

28

List the three different types of microtubules involved in mitotic spindle assembly

1. astral microtubule (anchors the two poles)
2. kinetochore microtubule (attaches to chromosome; then movement starts)
3. interpolar microtubule (keeps poles apart)

29

Which end is associated with the spindle pole?

minus end

30

Microtubules from opposite poles are attached to ______ of sister chromatids

kinetochores, which are located at the centromere

31

How are the chromosomes oriented during metaphase?

chromosomes are aligned on the metaphase plate

32

What happens to the sister chromatids during anaphase?
Kinetochore microtubules lengthen or shorten?

sister chromatids separate to form two daughter chromosomes; pulled towards opposite poles

33

What occurs during telophase?

nuclear envelope reassembly which marks the end of mitosis