Lecture A4

Question 1

_____ is necessary to create the ___ different cell types in human body from a single cell zygote

Answer 1

-cell division
-200

Question 2

5 types of proteins that regulate the cell cycle

Answer 2

I. Growth Factors
II. Growth Factor Receptors
III. Signal Transduction Proteins
IV. Transcription Factors
V. Cell-Cycle Regulators

Question 3

Phases of the cell cycle

Answer 3

-Go
-G1
-S (DNA replication)
-G2
-M (nuclear division)
-Cytokinesis (cytoplasmic division)

Question 4

Go phase (def.)

Answer 4

is a form of the resting state, or quiescence, in which cells reside until they receive appropriate signals that tell them to enter cell cycle (G1 extended)

Question 5

Go cells are ____

Answer 5

quiescent (doing their specialized tasks)

Question 6

Most of your cells are in this phase: ____

Answer 6

Go

Question 7

______ control progression through the cell cycle

Answer 7

Cyclin and Cyclin Dependent Kinase (CDK) proteins

Question 8

Cyclins associated with Go

Answer 8

-Cyclin D
-CDK4
-CDK6

Question 9

Cyclins associated with G1 (before restriction point in late G1)

Answer 9

-G1 cyclins
-Cyclin D

Question 10

Cyclins associated with G1 (after restriction point in late G1)

Answer 10

-Cyclin E
-CDK2

Question 11

Cyclins associated with early S

Answer 11

-S cyclins
-S-phase-promoting factor(SPF) (CDK)

Question 12

Cyclins associated with S

Answer 12

-Cyclin A
-CDK2

Question 13

Cyclins associated with end of G2/start of M

Answer 13

-M cyclins
- M-Phase-promoting factor (MPF) -CDK

Question 14

Cyclins associated with M

Answer 14

-Cyclin B
-CDK1

Question 15

APC is ____ and does what?

Answer 15

-Anaphase-promoting complex
-a ubiquitin ligase that marks cell cycle proteins for degradation to cause anaphase

Question 16

end of G1 phase is marked by _____

Answer 16

degradation of G1 cyclins, cyclin E

Question 17

end of S phase is marked by _____

Answer 17

degradation of S cyclins, cyclin A

Question 18

end of M phase is marked by _____

Answer 18

degradation of M cyclins, cyclin B

Question 19

Go cells don’t pass this point?

Answer 19

restriction point

Question 20

Cyclin D builds when? peaks when?

Answer 20

-G1
-G1

Question 21

Cyclin E builds when? peaks when?

Answer 21

-G1
-G1/S

Question 22

Cyclin A builds when? peaks when?

Answer 22

-G1/S
-S

Question 23

Cyclin B builds when? peaks when?

Answer 23

-S
-M

Question 24

Go cells partly _____ and exit the cycle to _____ state

Answer 24

-disassemble their cell-cycle control system
-specialized, non-dividing state

Question 25

Go state and its reversibility is dependent on _____

Answer 25

cell type

Question 26

cell cycle length depends on _____

Answer 26

time spent in G1/Go

Question 27

______ are in a terminally differentiated G0 state

Answer 27

Neurons and skeletal muscle cells

Question 28

terminally differentiated G0 state means that ______

Answer 28

the molecules of the cell-cycle control system are no longer expressed and cell division never occurs

Question 29

Type of cells in Go but are not terminally differentiated Go+ situation that makes them enter cell cycle

Answer 29

-hepatocytes (stimulated to divide if the liver
is damaged)
-lymphocytes (need)

Question 30

Maintenance of __________ (4) needs constant cell division so they are most affected by _____

Answer 30

-skin, blood, hair, gut
-chemotherapy

Question 31

gut stem cells are found where? then they differentiate + migrate to _____

Answer 31

-the bottom of the crypts
-the top and undergo apoptosis

Question 32

what is scarring?

Answer 32

failure of cell division + cell differentiation

Question 33

signalling pathways that control cell diversity also impact _____

Answer 33

the cell cycle

Question 34

Mitogens are ______

Answer 34

subset of cell-extrinsic signalling molecules that can modify the cell cycle

Question 35

master TF that controls cell cycle

Answer 35

Myc

Question 36

Myc (def.)

Answer 36

a transcription factor that regulates cell cycle genes like CycD and E2F and itself

Question 37

SCF (def.)

Answer 37

a factor that regulates degradation of Cyclin proteins

Question 38

E2F (def.)

Answer 38

a transcription factor that regulates key cell cycle genes and entry into S phase

Question 39

Myc gene is activated through ____

Answer 39

Ras- Map K pathway

Question 40

In G1 cells, E2F is activated by _____

Answer 40

the inhibition of Rb (which normally inhibits E2F) by cyclin D1-CDK4 complex

Question 41

In non-proliferating cells, E2F is _____

Answer 41

inhibited by active Rb

Question 42

In proliferating cells, E2F is _____

Answer 42

activated by release of inactivated Rb that as been phosphorylated by active cyclin D1-CDK4 complex

Question 43

_____ acts as an anti-mitogen inducing cells _____

Answer 43

-TGF-β
-to enter G0

Question 44

Anti-mitogens are also called _____

Answer 44

-anti-growth factors

Question 45

Commitment (def.)

Answer 45

a change in gene expression has occurred but the effect of the translated proteins has not yet been realized

Question 46

______ is needed to make neurons from neuronal progenitor cells

Answer 46

Entry into G0 coupled with expression of proneural
transcription factors