Regulation of cell cycle & Cancer cell

Question 1

What is the main role of checkpoints throughout the cell cycle?

Answer 1

It controls and regulates the cell cycle.

Question 2

What are two signals that the cell receives from checkpoints?

Answer 2

Stop/Go signals.

Question 3

What is the most important checkpoint?

Answer 3

G1 checkpoint is the most important checkpoint.

Question 4

What are some things that should be checked for G1 checkpoints?

Answer 4

Cell size, growth factors, and DNA damage.

Question 5

What is the key event for the go signal during the G1 checkpoint?

Answer 5

Cell completes whole the cell cycle.

Question 6

What is the key event for the stop signal during the G1 checkpoint?

Answer 6

Cell enters a nondividing state known as a G0 phase.

Question 7

What types of cell stays at G0 checkpoint?

Answer 7

Muscle/nerve cells stay at G0 checkpoint.

Question 8

What are some things that should be checked for G2 checkpoints?

Answer 8

Completion of DNA replication and DNA damage.

Question 9

What is the key event for the go signal during the G2 checkpoint?

Answer 9

Cell proceeds mitosis.

Question 10

What is the key event for the stop signal during the G2 checkpoint?

Answer 10

Cell cycle sops and the cell will attempt to repair damage. If damage cannot be repaired the cell will undergo apoptosis (Programmed cell death).

Question 11

What are some things that should be checked for M checkpoints?

Answer 11

Checks for microtubule attachment to chromosomes at the kinetochores at metaphase.

Question 12

What is the key event for the go signal during the M checkpoint?

Answer 12

Cell proceeds to anaphase and completes mitosis.

Question 13

What is the key event for the stop signal during the M checkpoint?

Answer 13

Cell will pause mitosis to allow for spindles to finish attaching to chromosomes.

Question 14

What are two internal cell cycle regulators?

Answer 14

Cyclins(proteins) and CDKs(enzymes known as cyclin-dependent kinases)

Question 15

What are the main characteristics of cyclins?

Answer 15

Concentration of cyclins varies.

Question 16

What are the main characteristics of CDKs?

Answer 16

Concentration remains constant through each phase of the cell cycle.

Question 17

What are three external cell cycle regulators?

Answer 17

Growth factors, Contact (pr density) inhibition, and anchorage dependence.

Question 18

What are Growth factors?

Answer 18

They are hormones released by cells that stimulate cell growth.

Question 19

What is Contact inhibition?

Answer 19

Cell surface receptors recognize contact with other cells.

Question 20

What is Anchorage dependence?

Answer 20

Cells rely on attachment to other or the extracellular matrix to divide.

Question 21

How do normal cells become cancerous?

Answer 21

Through DNA mutations normal cells become cancerous.

Question 22

What are the three traits of normal cells?

Answer 22

They follow checkpoints. They divide on average 20~50 times in culture (in petri dish). Go through apoptosis when there are significant errors.

Question 23

What are the three traits of cancer cells?

Answer 23

Do not follow checkpoints. They can divide infinitely when in culture (considered to be immortal). Evade apoptosis and continue dividing even with errors.