Lecture 20 - Cell Cycle

Question 1

What are the two general phases of the cell cycle?

Answer 1

Interphase and M Phase

Question 2

Interphase is comprised of

Answer 2

G1, S, G2

Question 3

In what phase is the cell not dividing?

Answer 3

Interphase

Question 4

In what phase is the cell dividing?

Answer 4

M Phase

Question 5

G1 Phase of Interphase

Answer 5

The first phase of cell growth and organelle duplication

Question 6

G0 Phase

Answer 6

When a cell exits the cell cycle either permanently or for long periods of time; the cell stops expressing genes required for the cell cycle.

Question 7

Examples of cells in G0

Answer 7

nerve, muscle, cardiac cells

Question 8

S Phase

Answer 8

DNA Replication

Question 9

How many chromosomes are replicated during S Phase?

Answer 9

46

Question 10

What copies DNA during S Phase?

Answer 10

DNA Polymerase

Question 11

What holds two strands of DNA together?

Answer 11

hydrogen bonds

Question 12

What holds chromosomes together?

Answer 12

Cohesions

Question 13

Steps to DNA Replicaiton

Answer 13

1. Unzipping
2. DNA Polymerase makes a copy using base pairing rules
3. Sugar phosphate backbone formed connecting nucleotides in the two new strands

Question 14

G2 Phase of Interphase

Answer 14

The second phase of cell growth and organelle duplication

Question 15

M Phase

Answer 15

Mitosis and Cytokinesis

Question 16

Mitosis Steps

Answer 16

Prophase, Prometaphase, Metaphase, Anaphase, Telophase

Question 17

Mitosis

Answer 17

Nuclear Division

Question 18

Prophase

Answer 18

The replicated chromosomes condense. The centrosomes begin to move to opposite sides of the nucleus and the mitotic spindles begin to form.

Question 19

Prometaphase

Answer 19

nuclear envelope breaks down, spindle fibers contact at the kinetochore located at centromeres

Question 20

Kinetochore

Answer 20

protein complexes which assemble on the condensed chromosomes

Question 21

Metaphase

Answer 21

Mitotic spindle gathers all the chromosomes to the center of the spindle

Question 22

Anaphase

Answer 22

The two sister chromatids in each replicated chromosome synchronously split apart. The spindle draws them to opposite poles of the cell.

Question 23

Specifically, when does anaphase begin?

Answer 23

When the cohesions are cleaved

Question 24

Steps of Coheasins Cleavage

Answer 24

1. APC phosphorylated by MCdk
2. Phosphorylated APC activated when Cdc20 binds
3. Activated APC ubiquinates securin
4. Securin is degraded and separase is activated
5. Separase cleave cohesins

Question 25

Telophase

Answer 25

Nuclear envelope reassembles around each of the two sets of separated chromosomes to form two nuclei. Nucleus expands and chromosomes condense to interphase state. Contractile ring assembles.

Question 26

Cytokinesis

Answer 26

cytoplasmic division, including all organelles, by the contractile ring

Question 27

When does cytokinesis begin and end?

Answer 27

Begins in anaphase and ends at the end of telophase