topic 1-b2

Question 1

Determines whether all conditions are favorable for cell
division to proceed, also called the restriction point (in yeast), is a point at which the cell irreversibly commits to the cell division process.

Answer 1

G1 checkpoint

Question 2

If the G1/S checkpoint detects damage, the ______ protein targets the cell for regulated death

Answer 2

p53

Question 3

What is apoptosis?

Answer 3

Process or programmed cell death, eliminating unwanted cells.

Question 4

A cell that does not meet all the requirements will not be allowed to progress into the _____.

Answer 4

S phase

Question 5

The cell can halt the cycle and attempt to remedy the problematic condition, or the cell can advance into ___ and await further signals when conditions improve.

Answer 5

G0

Question 6

Bars entry into the mitotic phase if certain conditions are not met.

Answer 6

G2 checkpoint

Question 7

What is the important role of G2 checkpoint?

Answer 7

To ensure that all of the chromosomes have been replicated and that the replicated DNA is not damaged.

Question 8

If the checkpoint mechanisms detect problems with the DNA, the cell cycle is ______, and the cell attempts to either complete DNA replication or repair the damaged DNA.

Answer 8

Halted

Question 9

Occurs near the end of the metaphase stage of karyokinesis.

Answer 9

M checkpoint

Question 10

M checkpoint is also known as?

Answer 10

As the spindle attachment checkpoint, because it determines
whether all the sister chromatids are correctly attached to the spindle microtubules.

Question 11

What are two groups of intracellular molecules that regulate the cell cycle?

Answer 11

Promote progress of the cell to the next phase (positive regulation) or halt the cycle (negative regulation).

Question 12

Two group of proteins that are responsible for the progress of the cell through the various checkpoints.

Answer 12

Cyclins and cyclin‐dependent kinases

Question 13

It regulate the cell cycle only when they are tightly bound to Cdks.

Answer 13

Cyclins

Question 14

In initiation of mitosis, this is a factor that protein complex which initiates the mitotic phase of the cell cycle.

Answer 14

Mitosis-promoting factor

Question 15

2 proteins in mitosis promoting factor?

Answer 15

Cyclin B and CDC2

Question 16

It is one that oscillates in quantity during the cell cycle.

Answer 16

Cyclin B

Question 17

One whose quantity is constant encoded by the ____.

Answer 17

CDC2 gene

Question 18

It is only functional when it is combined with cyclin which
is referred as cyclin‐dependent kinase (CDK)

Answer 18

CDC2 kinase

Question 18

An enzyme that transfers a phosphate group on
to a protein by phosphorylation

Answer 18

Kinase

Question 19

Once mitosis has been initiated, anaphase‐promoting complex (APC) or cyclosome:

Answer 19

1. Degrades the Cyclin B protein of MPF
2. Permits the separation of the sister chromatids at the
   start of anaphase

Question 20

What are the negative regulatory molecules, all three of these regulatory proteins were discovered to be damaged or non‐functional in cells that had begun to replicate
uncontrollably (became cancerous).

Answer 20

Retinoblastoma protein (Rb), p53, and p21.

Question 21

Are a group of tumor‐suppressor proteins common
in many cells.

Answer 21

Retinoblastoma protein

Question 22

These designations refer to the functional molecular masses of the proteins (p) in kilodaltons.

Answer 22

53 and 21

Question 23

Rb, p53, and p21 act primarily at the ______.

Answer 23

G1 checkpoint

Question 24

A multi‐functional protein that has a major impact on the commitment of a cell to division

Answer 24

p53

Question 25

Why does p53 has major impact on the commitment of a cell to division?

Answer 25

Because it acts when there is damaged DNA in cells that are undergoing the preparatory processes during G1.

Question 26

What happens if p53 level rises?

Answer 26

p21 is triggered

Question 26

If the DNA cannot be repaired, p53 can trigger ______, or cell suicide, to prevent the duplication of damaged chromosomes.

Answer 26

Apoptosis

Question 26

It enforces the halt in the cycle dictated by p53 by binding to and inhibiting the activity of the Cdk/cyclin complexes.

Answer 26

p21

Question 27

As a cell is exposed to more stress, higher levels of p53 and p21 accumulate, making it less likely that the cell will move into the _______.

Answer 27

S phase

Question 28

It exerts its regulatory influence on other positive regulator protein, and monitors cell size.

Answer 28

Retinoblastoma protein

Question 29

Rb binds to proteins called

Answer 29

Transcription factors

Question 30

When Rb is bound to E2F, production of proteins necessary to G1/S transition is ____.

Answer 30

Blocked

Question 31

What happens to Rb as cell increases in size?

Answer 31

Rb is slowly dephosphorylated until it becomes inactivated.

Question 32

Rb and other proteins that negatively regulate the cell cycle are sometimes called ____.

Answer 32

Tumor suppressors

Question 33

Describe apoptosis

Answer 33

It occurs in normal development when cells are temporarily required for a maturation process. When older cells are no longer necessary or when cells are genetically damaged, they too are detected and signaled to undergo apoptosis (programmed cell death).

Question 34

Describe necrosis

Answer 34

Cells that die unexpectedly from injury undergo necrosis , an accidental rather than a programmed death.

Question 34

What happens to the nucleus in necrotic cells?

Answer 34

Does not shrink or fragment.

Question 35

What happens to the blebs in apoptotic cells

Answer 35

Surround cell contents including organelles. The blebs disrupt the cell into apoptotic bodies.

Question 35

What happens to the blebs in necrotic cells?

Answer 35

They form but eventually fuse

Question 35

What happens to the nucleus in apoptotic cells?

Answer 35

Does fragment

Question 36

What happens to the cell membrane in necrotic cells?

Answer 36

Eventually bursts and cell contents are released into extracellular environment.

Question 37

What happens to the cell contents in apoptotic cells?

Answer 37

Cell contents are not released into the extracellular environment.