Cell Division and Cell Cycle

Question 1

4 stages of mitosis

Answer 1

1. Prophase
2. Metaphase
3. Anaphase
4. Telophase

Question 2

3 groups of proliferative potential

Answer 2

1. Labile cells
2. Stable cells
3. Permanent cells

Question 3

Labile cells aka?

Answer 3

Continuously dividing

Question 4

Examples of labile cells

Answer 4

1. Epithelium (skin, oral cavity, repro organs, GI)
2. Salivary glands
3. Exocrine pancreas
4. Hematopoietic cells of bone marrow

Question 5

Stable cells aka?

Answer 5

Quiescent cells

Question 6

Examples of stable cells

Answer 6

1. Parechyma (liver, kidney, pancreas)
2. Vascular endothelial cells
3. Smooth muscle cells

Question 7

Stable cell cycle

Answer 7

Rest in G(0) but can be driven to re-enter G(1)

Question 8

Labile cell cycle

Answer 8

Proceed through cell cycle continuously

Question 9

Permanent cell cycle

Answer 9

Have exited cell cycle → cannot re-enter

Question 10

Examples of permanent cells

Answer 10

1. Nerve cells
2. Cardiac myocytes
3. Skeletal muscle

Question 11

Can fully differentiated cells regenerate?

Answer 11

No

Question 12

Tissues must have ___ cells to regenerate

+ an example of an organ which doesn’t have any

Answer 12

Stem cell

Heart

Question 13

Life cycle of stem cells in GI tract

Answer 13

1. “Born” by stem cell division
2. Migrate to top of villi while differentiating
3. At top → die and shed into lumen

Question 14

Transition time of epithelial cells in lumen

Answer 14

3-5 days

Question 15

Inhibition of CO-1 leads to?

Answer 15

Depletion of stem cells and ulcerations

Question 16

3 methods of transmitting growth signals

Answer 16

1. Growth factors
2. Steroid hormones (estrogen, testoserone)
3. other hormones (NE)

Question 17

3 cell cycle checkpoints

Answer 17

1. G1/S checkpoint
2. M checkpoint
3. G2/M checkpoint

Question 18

Questions cell asks itself at G1/S checkpoint

Answer 18

1. Growth signal?
2. Cell size?
3. Environment?
4. DNA ok?

Question 19

Questions cell asks at G2/M checkpoint?

Answer 19

1. DNA duplication ok?

2. Cell size

Question 20

Questions cell asks at M checkpoint?

Answer 20

Are chromosomes correctly distributed?

Question 21

pRB stands fo?

Answer 21

Retinoblastoma protein

Question 22

Function of pRB

Answer 22

Holds transcription factors inactive → prevents transcription until growth signal arrives

Question 23

pRB is involved with which checkpoint?

Answer 23

G1/S checkpoint

Question 24

Growth signals cause transcription of?

Answer 24

Cyclins D, A and B

Question 25

CDK stands for?

Answer 25

Cyclin-dependent kinase

Question 26

CDK forms complex with?

Answer 26

Cyclin D

Question 27

CDK-cyclin D complex does what?

Answer 27

Phosphorylates pRB

Question 28

Phosphorylation of pRB does what?

Answer 28

Releases transcription factors

Question 29

Released transcription factors do what?

Answer 29

Induce transcription of proteins → necessary for duplication of chromosomes (S-phase)

Question 30

If cell senses injury, it will transcribe?

Answer 30

p53

Question 31

p53 function

Answer 31

1. Halts cell cycle | 2. Induces transcription of repair enzymes

Question 32

How does p53 halt cell cycle?

Answer 32

Prevents growth signal from activating transcription of cyclins

Question 33

What occurs during interphase?

Answer 33

1. Duplication of centrosome | 2. Duplication of decondensed chromosomes in nucleus

Question 34

What occurs during mitosis?

Answer 34

Chromosomes condense with 2 sister chromatomes

Question 35

Nuclear envelope during mitosis

Answer 35

Intact

Question 36

Prometaphase

Answer 36

1. Nuclear envelope fragmented | 2. Chromosome in active motion

Question 37

Metaphase

Answer 37

Kinetechores of all chromosomes align in mindle Spindle poles start to move toward ends

Question 38

Anaphase

Answer 38

Spindle poles move daughter chromosomes apart

Question 39

Telophase

Answer 39

Nuclear envelope begins to reassemble

Question 40

Cytokinesis

Answer 40

1. Completed nuclear envelope surrounds decondensing chromosomes 2. Contractile ring creating cleavage furrow

Question 41

Phases of cell cycle

Answer 41

1. G(0) 2. G1 3. S 4. G2 5. M

Question 42

G1 = ?

Answer 42

Gap: growing phase

Question 43

S = ?

Answer 43

DNA synthesis

Question 44

G = ?

Answer 44

Gap: growing phase

Question 45

M = ?

Answer 45

Mitosis: nuclear and cellular division