Cell cycle

Question 1

What is Interphase?

Answer 1

Interphase consists of G1, Synthesis, and G2 phases.

Question 2

What occurs during G1 (Gap 1)?

Answer 2

Growth of the cell and checks of the DNA.

Question 3

What occurs during Synthesis phase?

Answer 3

Duplication of chromosomes.

Question 4

What occurs during G2 (Gap 2)?

Answer 4

Checks DNA synthesis completed properly and further growth.

Question 5

What is Mitosis?

Answer 5

Mitosis is the process of cell division that includes Prophase, Prometaphase, Metaphase, Anaphase, Telophase, and Cytokinesis.

Question 6

What happens during Prophase?

Answer 6

Condensing of chromosomes, formation of kinetochores, nuclear envelope breaks down, and mitotic spindle forms.

Question 7

What happens during Prometaphase?

Answer 7

Duplicated chromosomes attach to the spindle.

Question 8

What happens during Metaphase?

Answer 8

Chromosomes align at the cell equator.

Question 9

What happens during Anaphase?

Answer 9

Sister chromatids separate and move towards the spindle poles.

Question 10

What happens during Telophase?

Answer 10

Chromosomes decondense, nuclear envelope reforms, and spindle disappears.

Question 11

What is Cytokinesis?

Answer 11

Physical separation into two new daughter cells at the end of mitosis.

Question 12

What is G0 phase?

Answer 12

Resting phase, out of the cycle; differentiated cells are normally in G0.

Question 13

What is Meiosis?

Answer 13

Meiosis involves DNA replication prior to meiosis I and results in four haploid nuclei.

Question 14

What is the purpose of Meiosis?

Answer 14

Ensures the next generation has a diploid number of cells and a combination of traits different from either parent.

Question 15

What occurs during Prophase 1 of Meiosis?

Answer 15

Dyad pairs align to create tetrads and crossing over occurs.

Question 16

What occurs during Metaphase 1 of Meiosis?

Answer 16

Spindle fibers attach to dyad at kinetochore, aligning tetrads at the cell equator.

Question 17

What occurs during Anaphase 1 of Meiosis?

Answer 17

Chiasmata break apart and sister chromatids migrate to opposite poles.

Question 18

What occurs during Telophase 1 of Meiosis?

Answer 18

Cleavage furrow forms, initiating cytokinesis.

Question 19

What is Interkinesis?

Answer 19

Rest period between meiosis 1 and meiosis 2.

Question 20

What occurs during Meiosis 2?

Answer 20

Similar to mitosis but with only 23 chromosomes.

Question 21

What are Cyclins?

Answer 21

Regulatory subunits governing progression of the cell cycle.

Question 22

How many Cyclins are there?

Answer 22

There are 13+ cyclins.

Question 23

How are Cyclins degraded?

Answer 23

Degraded via the ubiquitin/proteosome pathway.

Question 24

What is the role of Cyclin D?

Answer 24

Promotes G0 to G1 transition and G1 progression.

Question 25

What is the function of Cyclin E?

Answer 25

Initiation and progression of DNA replication.

Question 26

What is the role of Cyclin A?

Answer 26

Initiation and progression of DNA replication.

Question 27

What is the function of Cyclin B?

Answer 27

Entering mitosis and progression past anaphase.

Question 28

What does Rb regulate?

Answer 28

Rb regulates the activity of TF E2F, which controls the expression of cyclins and genes needed in S phase.

Question 29

What happens to Rb in the resting state (G1)?

Answer 29

Rb binds and inhibits E2F, blocking transactivation.

Question 30

What is the effect of growth factor stimulus on Rb?

Answer 30

Stimulates expression of Cyclin D, which phosphorylates Rb and releases E2F.

Question 31

What are Cyclin dependent kinases (CDKs)?

Answer 31

Enzymes that regulate the cell cycle by associating with cyclins.

Question 32

What is the role of CDK inhibitors?

Answer 32

They bind to CDKs and interfere with their activity.

Question 33

What is the significance of p21?

Answer 33

Inhibits virtually all CDKs and mediates G arrest in DNA damage.

Question 34

What is the role of p27?

Answer 34

Implicated in G1 arrest and inhibits Rb phosphorylation.

Question 35

What is the cell cycle in embryonic stem cells?

Answer 35

Greatly reduced time in G phase and increased time in S phase.

Question 36

How do cyclins relate to cancer?

Answer 36

Cyclins can be overexpressed in cancers, leading to uncontrolled cell cycle progression.

Question 37

What is the effect of recombinant adenovirus expressing p27?

Answer 37

Induces cell cycle arrest and loss of cyclin-CDK activity in breast cancer cells.

Question 38

What is the role of chemotherapy in relation to CDKs?

Answer 38

Inhibition of CDKs leads to inhibition of cell cycle progression.

Question 39

What are cell cycle checkpoints?

Answer 39

Defective in cancer cells, they can be targeted for treatment.