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Biochem Block 3 > Cell cycle > Flashcards

Flashcards in Cell cycle Deck (51):
1

interphase

-cell undergoes normal growth and metabolism
-prepares for cell division
-Gap 1
-Synthesis of DNA
-Gap 2

2

Gap 1

-G1
-active metabolism
-accumulation of building blocks and energy

3

Synthesis of DNA

-S
-DNA replication occurs
-each DNA molecule produces identical copy
-cetrosome is duplicated

4

Gap 2

-G2
-active metabolism
-protein synthesis
-duplication of organelles
-once in this phase, everything is sped up

5

G0

-resting
-a period in the cell cycle in which the cell is not dividing of preparing to divide

6

Quiescent state

-G0 resting state
-cell is not dividing or preparing to divide

7

terminally differentiated state

-cells that leave the cell cycle and do not re-enter the cell cycle
-cells just die and get replaced
-skin cells

8

reversible quiescent G0 phase

-capable to return to the cell cycle
-stem cells
-hepatocytes

9

Mitotic phases

-prophase
-prometaphase
-metaphase
-anaphase
-telophase
-cytokinesis

10

prophsae

-chromosomes condense and become visible
-spindle fibers emerge from centrosomes
-break down nuclear envelope
-nucleolus disappears

11

prometaphase

-chromosomes condense more
-kinetochores appear at centromeres
-miotic spindle microtubules attach to kinetochores
-centrosomes move toward opposite poles

12

metaphase

-miotic spindle is fully developed
-centrosomes are at opposite poles
-chromosomes lined up in the middle
-each sister chromatid is attached to a spindle fiber

13

anaphase

-cohesion proteins that bind sister chromatids break down
-sister chromatids change names and are pulled toward poles
-non-kinetochore spindle fibers lengthen to elongate cell

14

when do sister chromatids change names and what is their new name

-anaphase
-chromosomes

15

telophase

-chromosomes make it to opposite poles and decondense
-nuclear envelope surrounds each set of chromosomes
-mitotic spindles break down

16

Cytokinesis animal cells

-cleavage furrow separates the daughter cells

17

cytokinesis plant cells

-cells plate separates daughter cells

18

How many internal checkpoints are there?

3

19

G1 checkpoint

-restriction
check for..
-cell size
-nutrients
-growth factors
-DNA damage

20

G2 checkpoint

check for...
-cell size
-accurate DNA replication
-if mistakes, the cell cycle will stop
-avoid producing mutated cell

21

M checkpoint

check for...
-chromosome attachment to the spindle
-make sure they separate into each daughter cell

22

positive regulation molecules

-cyclins
-Cdk

23

positive regulation

-allow cell to move to the next phase

24

cyclins

-changes of different cyclins throughout the cell cycle
-direct correlation between cyclin accumulation and the 3 checkpoints
-sharp decline in cyclin levels following each checkpoint

25

what degrades cyclins?

-cytoplasmic enzymes

26

when are cyclins active?

-when bond to respective Cyclin-dependent kinase

27

Cdk

-cyclin binds to Cdk
-complex is phosphorylated
-activated complex phosphorylates target protein
-active target protein advances through the cell cycle

28

What cyclin is continuously on throughtout the cell cycle>

-Cyclin D

29

Negative regulation molecules

-Rb
-p53
-p21

30

Rb regulation of the cell

-negative regulation
-controls transcription of genes necessary for transition into S phase
-UNphosphorylated Rb binds to transcription factor E2F so it cannot bind to DNA and transcription is blocked

31

phosphorylated Rb

-triggered by cell growth
-releases E2F
-allows advancing in the cell cycle

32

Rb

-retinoblastoma protein
-prevents initiation of the cell cycle in G1 phase

33

p53 regulation of the cell

-transcriptional repressor
-can repress transcription and promote apoptosis through interaction of apoptotic regulators in cytosol
-detects cell damage

34

what can p53 do to the cell cycle?

1. program for apoptosis
OR
2. recruit proteins to help the damage then restart the cell cycle

35

p21 regulation of the cell

-inhibiting the activity of cyclin E-associated CDK2
-prevents E2F-mediated gene transcription and cell cycle progression
-induced in response to p53

36

Mitogens

-EXTERNAL stimuli that cause the cells to proliferate
-make cell return to G1 if in G0
-starts cell division

37

intergins

-mitogens provided by extracellular matrix

38

mitogenic

-cell-to matrix contact

39

antimitogenic

-cell-to-cell contact
-contact inhibition
-there are too many cells! stop dividing!

40

distant sources that supply extracellular signals

-growth factors
-cytokines

41

platelet derived growth factor

-PDGF
-participates in wound healing

42

epidermal growth factor

-produced locally, used locally
-stimulates proliferation of epithelial cells
-primarily acts in tissue of origin

43

fibroblast growth factors

-family of 22 proteins that act on 4 different tyrosine kinase receptors
-stimulate fibroblasts and other cells!

44

insulin like growth factor 1

-released from the liver in response to growth hormone

45

vascular endothelial growth factor
**********

-VEGF
-produced by cells that stimulate vasculogenesis and angiogenesis
-new blood vessel formation
-important for wet AMD

46

nerve growth factor

-stimulates the growth and differentiation (BUT NOT MITOSIS) of postganglionic sympathetic neurons

47

what leads to cancer?
*********

-unregulated cell cycle

48

six hallmarks of cancer

-cell growth and division absent of proper signals
-continuous growth contrary to signals
-avoidance of apoptosis
-limitless cell division
-promoting blood vessel construction
-invasion of tissue

49

oncogenes
********

-mutated NORMAL genes
-encode POSITIVE cell cycle regulators
-mutated and stimulated all the time

50

Tumor suppressor genes
********

-genes that encode for NEGATIVE cell cycle regulators
-stops the cell cycle

51

mutated p53

-does not detect mutations and does not stop cell cycle