BSI Lecture 20 Cell Cycle

Question 1

How does APC trigger anaphase?

Answer 1

Ubiquitilate of securin

Question 2

How does activation of the APC complex lead to separation of the sister chromatids?

Answer 2

The APC complex causes ubiquitylation and degradation of securin, activating ubiquitin separase, which separates the chromatids

Question 3

DNA Replication; what are the 3 steps?

Answer 3

1) Unzipping
2) Complementary base pairing
3) Sugar-phosphate backbone formed connecting nucleotides in the 2 new strands

Question 4

Segregation of the sets of chromosomes to opposite ends of the spindle occur in which phase?

Answer 4

Anaphase

Question 5

Nucleus expands and chromosomes decondense to interphase state, what phase does this occur in?

Answer 5

Telophase

Question 6

Assembly of contractile ring necessary for cytokinesis occurs in which phase?

Answer 6

Telophase

Question 7

Which enzyme replicates DNA?

Answer 7

DNA Polymerase

Question 8

What are the phases of mitosis?

Answer 8

Prophase
Prometaphase
Metaphase
Anaphase
Telophase

Question 9

What are the two general phases of the cell cycle?

Answer 9

Interphase and M-phase

Question 10

Interphase consists of which phases?

Answer 10

G1, S, G2

Question 11

Where on the chromosomes are kinetochores located?

Answer 11

On the centromeres of sister chromatids

Question 12

What is cytokinesis?

Answer 12

Division of cytoplasm (including all organelles) by the contractile ring which pinches the two daughter cells part.

Question 13

How is APC activated?

Answer 13

M-Cdk phosphorylates APC, then Cdc20 binds to APC, activating it.

Question 14

Give two examples of cell types that remain in G0 permanently?

Answer 14

Differentiated nerve and muscle cells.

Question 15

Replicated chromosomes condenses in what phase?

Answer 15

Prophase

Question 16

T or F? The nuclear envelope is still intact during prophase.

Answer 16

True

Question 17

Nuclear envelope breaks down during which phase?

Answer 17

Prometaphase

Question 18

_______ are protein complexes which assemble on the condensed chromosomes.

Answer 18

Kinetochores

Question 19

How many chromosomes are copied?

Answer 19

46

Question 20

In what phase do the sister chromatids separate?

Answer 20

Anaphase

Question 21

Mitosis and cytokinesis are a part of which phase?

Answer 21

M-phase

Question 22

What occurs in G1 phase?

Answer 22

Cell growth (organelles)

Question 23

What event occurs during S phase?

Answer 23

Replication of genome (DNA synthesis)

Question 24

What proteins bind together the sister chromatids?

Answer 24

Cohesin

Question 25

What occurs during G2 phase?

Answer 25

Cell growth (produces proteins and enzymes necessary for cell division)

Question 26

What is mitosis?

Answer 26

Nuclear division

Question 27

What is the mitotic spindle?

Answer 27

Microtubules that extend from centrosomes and bind to the kinetochores

Question 28

What are kinetochores?

Answer 28

Kinetochores are protein complexes which assemble on the condensed chromosomes.

Question 29

What phase(s) of M phase does cytokinesis occur?

Answer 29

Begins in anaphase and is complete by the end of telophase

Question 30

What is the function of the contractile ring and what is it composed of?

Answer 30

Contractile ring is composed of actin and myosin filaments which pinch the cell in two. This divides them into two daughter cells, each with one nucleus.

Question 31

Describe G0 phase.

Answer 31

Cells that remain in G1 phase for long periods of time or permanently.

Question 32

Some cells remain in this phase for long periods of time or permanently is then called _______

Answer 32

G0

Question 33

Centrosomes start to move to the opposite sides of the nucleus occurs in what phase?

Answer 33

Prophase

Question 34

_____ shoots out microtubules to form mitotic spindles.

Answer 34

Centrosomes

Question 35

Nuclear envelope breaking down allows the spindle microtubules to contact the condensed ________

Answer 35

Chromosomes

Question 36

Microtubules binds to _________ located at centromeres of sister chromatids

Answer 36

Kinetochores

Question 37

Mitotic spindles gathers all the chromosomes to the _____ of the spindle.

Answer 37

Center (equator)

Question 38

The phase when two sister chromatids in each replicated chromosome synchronously split apart.

Answer 38

Anaphase

Question 39

What draws the sister chromatids to opposite poles of the cell?

Answer 39

Spindle fibers

Question 40

______ begins abruptly with the release of the linkage that hold the sister chromatids together.

Answer 40

Anaphase

Question 41

Chromatids are pulled to the spindle pole to which it is attached occurs in which phase?

Answer 41

Anaphase

Question 42

Nuclear envelope reassembles around each of the two sets of separated chromosomes to form two nuclei, this occurs in which phase?

Answer 42

Telophase

Question 43

Division of the cytoplasm (including all organelles) by contractile ring which pinches the two daughter cells apart is what process?

Answer 43

Cytokinesis (Cytoplasmic Division)

Question 44

What begins in anaphase and is completed by the end of telophase?

Answer 44

Cytokinesis

Question 45

What can promote cell division?

Answer 45

Growth factors