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Flashcards in The Cell Cycle Deck (31)
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1

Roles of Cell division

Reproduction & Growth & Development

2

Prokaryotic cells undergo ______ ________ to divide because ________________________ and the result is _____________.

1. binary fission (NOT mitosis)
2. they are unicellular with a single circular chromosome (simpler than eukaryotes)
3. two genetically identical daughter cells

3

How do eukaryotic cells divide?

Mitosis

4

What is the centromere?

Site of attachment of chromatids and kinetochore

5

Name the four distinct phases of interphase

G1 -> S-phase -> G2 -> M phases

6

What happens during G1

GAP 1
- normal cell activities
- the cell is preparing to divide
- one copy of genome |

7

What happens during S phase

SYNTHESIS PHASE
1 copy of genome -> two copies
| -> |'|

8

What happens during G2

GAP 2
- normal cell activities
BUT cell is now committed to eventual mitosis

9

What happens during M phase

Mitosis (separation of chromatids)

10

Name the six phases of mitosis in order

Prophase -> Prometaphase -> Metaphase -> Anaphase -> Telophase -> Cytokinesis

11

Main process in prophase

Chromosomal condensation

12

How many chromosomes and chromatids are there in prophase

2 chromosomes, 4 chromatids

13

When do the microtubule organizing centers replicate

S phase

14

What happens to the microtubule organizing centers during prophase

They migrate away from the nucleus towards periphery of cell

15

How do microtubules move chromosomes in mitosis

- polymerization/depolymerization
- kinesin (+) end directed motor
- dyenin (DIE = negative) end directed motor

16

Main process of prometaphse

Nuclear envelope breakdown (NEBD), microtubules reach for chromosomes "fishing"

17

Stable attachment occurs when the microtubules attach to:
1.
2.
3.

1. kinetochore
2. other microtubules
3. membrane

18

What happens if the microtubules misses in prometaphase

it depolymerizes

19

Main process of Metaphase

Chromosomes line up at metaphase plate

20

How are chromosomes pushed to the middle in metaphase

Polymerization and kinesin

21

How are chromosomes pulled to the middle in metaphase

Depolymerization and dyenin

22

Main process of Anaphase

Separation of chromatids
|'| -> |' '|
TWO CHROMATIDS BECOME TWO CHROMOSOMES

23

How are chromosomes pulled to opposite poles in anaphase

Depolymerization and dyenin

24

How is the cell elongated in Anaphase

Overlapping microtubules (polar MTs) "pushing elbows out"

25

Main process of Telophase

Nuclear envelope reformation, chromosomal decondensation
"T for tit"

26

Main process of Cytokinesis

Separation of cytoplasm

27

How is the cytoplasm split during Cytokinesis

Microfilaments form cytokinetic furrow/contractile ring, myosin "walks" along MF to constrict flow

28

What are the three checkpoints of the cell cycle

1. Restriction point at G1/S: most important, are there signals/space/nutrients to divide? Once past restriction point, cell fated for division.
2. G2/M checkpoint: is DNA rep complete?
3. Metaphase/Anaphase checkpoint: are all kinetochores attached by MTs?

29

What is cancer

Uncontrolled cell division due to accumulation of mutations

30

The normal function of a tumor suppressor gene is ______________ and if a mutation interferes with this, it will lead to _________________. An example of a TSG is _____.

1. prevent passage through the cell cycle (brake pedal)
2. uncontrolled cell division
3. BRCAI (dysfunctional copy of genes predisposes you to breast cancer)