Cell cycle Flashcards

1
Q

What are the phases of the cell cycle

A

G1, S, G2 and M

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2
Q

Describe the characteristics of G1 phase

A

cell size maintained, nutritional control, variable length

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3
Q

What happens in S phase

A

DNA replication

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4
Q

Describe the characteristics of g2 phase

A

Growth, DNA has been replicated, centrosomes have been duplicated

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5
Q

How can you detect what phase of the cell cycle a cell is in

A

fluorescent DNA dyes determine DNA content in cells

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6
Q

How long is M phase

A

less than 1 hour in humans

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7
Q

What stage of M phase can cells pause

A

metaphase

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8
Q

What is the mitotic spindle comprised of

A

centrosomes, spindle microtubules and asters

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9
Q

What is the function of the mitotic spindle?

A

segregates chromosomes into daughter cells

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10
Q

What is the aster

A

radial array of short microtubules

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11
Q

what is the kinetochore?

A

large protein complexes

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12
Q

where does the kinetochore assemble

A

chromosomes and centromeres

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13
Q

What is the function of the kinetochore?

A

mediate attachment of mitotic spindle to microtubules

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14
Q

What are the different types of microtubules

A

astral microtubules, kinetochore microtubules, inter-polar microtubules

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15
Q

Which microtubules are structural

A

inter polar and astral

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16
Q

what is the function of kinetochore microtubules

A

pulls apart chromosomes

17
Q

What happens in prometaphase

A

nuclear envelop breaks down, attachment of chromosomes to spindle

18
Q

What happens in metaphase

A

chromosomes align on the equator, chromatids pulled towards pole

19
Q

what happens in telophase

A

new nuclear envelope forms, chromosomes de-condense

20
Q

What happens in cytokinesis

A

cytoplasm is divided in two by a contractile ring of actin and myosin filaments

21
Q

What are the checkpoints of the cell cycle?

A

G1 - S, G2-M and Metaphase - anaphase

22
Q

Which checkpoint operates through negative signalling ONLY

A

metaphase to anaphase

23
Q

What regulates the cell cycle

A

Cyclin activated kinases

24
Q

What do CDKs requires for functionality

A

cyclins

25
Q

TRUE or FALSE - levels of cyclins remain constant through the cell cycle

A

FALSE

26
Q

TRUE or FALSE - levels of CDKs remain constant through the cell cycle

A

TRUE

27
Q

how are cyclins degraded?

A

ubiquitin proteasome system

28
Q

what do cyclin-cdk complexes trigger

A

mitosis or DNA replication

29
Q

Which checkpoint checks DNA replication

A

G2/M

30
Q

What type of feedback loop operates M-cyclin/Cdk

A

positive

31
Q

What is M-cyclin/Cdk crucial for

A

rapidly activating mitosis

32
Q

What is the function of the metaphase-anaphase checkpoint?

A

Check chromosomes are attached to the spindle

33
Q

Describe the co-ordinated regulation of the cell cycle

A

phosphorylation of Cdk and synthesis & degradation of cyclins