Ch 12: Cell Cycle

Question 1

Define a Chromosome

Answer 1

A single long double helix of DNA wrapped around histones

A structure containing genetic information in the form of genes

Question 2

Define sister chromatids

Answer 2

Chromatid copies that remain attached at a centromere

Question 3

True or False: 2 sister chromatids attached at a centromere are counted as one chromosome

Answer 3

True

Question 4

Homologous chromosomes are:

Answer 4

Chromosomes that contain the code for the same genes but present with different alleles

Question 5

The spindle apparatus is formed by:

Answer 5

Microtubules formed by MTOCs

Question 6

A centrosome is formed by:

Answer 6

Two centrioles at 90 degree angles to eachother

Question 7

MTOC stands for

Answer 7

Microtubule Organization Center

Question 8

Centrosomes are this acronym

Answer 8

MTOCs

Question 9

An = B

Describe what the A and B coefficient/quantity is

Answer 9

A = Ploidy of a cell. If A=2 that means there are 2 homologous chromosomes paired together (for example human cells

B = Total number of chromosomes in a cell (46 in humans)

Question 10

Define a cell plate

Answer 10

In a plant cell, after telophase, a cell wall will be built to separate the daughter cells. This is a cell plate

Question 11

Define a cleavage furrow

Answer 11

When actin tightens to squeeze the cell membrane of the parent cell to separate the parent cell into two daughter cells

“The butt thing”

Question 12

List the steps of the M phase

Answer 12

PPMAT

Prophase
Prometaphase
Metaphase
Anaphase
Telophase

Question 13

Define a tumor supressor

Answer 13

Slows or stops cell cycle if DNA is damaged

Question 14

Define the function of p53

Answer 14

Slows or stops cell if DNA is damaged, and can trigger apoptosis if damage is too bad

Question 15

Define apoptosis

Answer 15

Spontaneous cell death

pop

Question 16

What happens during prophase

Answer 16

• Centromeres begin to form spindle apparatus

- Chromosomes condense for transport

Question 17

What happens prometaphase

Answer 17

• Nuclear envelope breaks down

- Microtubules contact chromosomes at kinetochores

Question 18

What happens during metaphase

Answer 18

• Chromosomes migrate to the middle of a cell

Question 19

What happens during anaphase

Answer 19

• Sister chromatids separate into daughter chromosomes

- Daughter chromosomes are pulled to opposite poles of the spindle apparatus

Question 20

What happens during telophase

Answer 20

• Nuclear envelopes form around the 2 groups of daughter chromosomes
• Chromosomes decondense

Question 21

Define proto-oncogene

Answer 21

A protein that promotes cell division when conditions are ideal to proceed (i.e. DNA is in-tact)

Question 22

The MPF dimer is made up of a ___ and a ___

Answer 22

Cyclin, Ckd (cyclin-dependent kinase)

Question 23

MPF stands for:

Answer 23

Mitosis-promoting factor

Question 24

The cyclin subunit of MPF functions as a _____________

Answer 24

regulatory protein

Question 25

Microtubules facilitate chromosome movement during anaphase using _______

Answer 25

Kinetochore proteins

Question 26

The G0 state describes:

Answer 26

A cell that is permanently stuck in the G1 phase A cell that has had its cell cycle arrested

Question 27

Cell cycle length varies among cell types primarily due to:

Answer 27

A difference in the length of time that the G1 phase takes

Question 28

Rapidly dividing cells essentially eliminate this phase of the cell cycle

Answer 28

G1

Question 29

MPF functions to:

Answer 29

Induce mitosis in all eukaryotes

Question 30

Cdk functions to:

Answer 30

Catalyze the transfer of a phosphate group from ATP to the target protein TL;DR: Catalyzes phosphorylation

Question 31

In mitosis, chromosome count only doubles during _____

Answer 31

Anaphase and Telophase

Question 32

Acronym for remembering the phases of mitosis

Answer 32

PPMAT ``` Prophase Prometaphase Metaphase Anaphase Telophase ```

Question 33

Meiosis produces _ daughter cells

Answer 33

4

Question 34

Ploidy refers to:

Answer 34

The number of sets of chromosomes

Question 35

This motor protein "walks" along microtubules to facilitate vesicle/organelle transport

Answer 35

Kinesin

Question 36

Cdk has an _____ and an _____

Answer 36

Active site, inactive

Question 37

Cdk functioning is dependent on ______

Answer 37

Cyclin binding to a Cdk

Question 38

Cancer involves a loss of _______

Answer 38

Cell cycle control

Question 39

Social control of the cell cycle in multicellular organisms refers to:

Answer 39

Cells being signaled to divide only when it is in the best interest of the whole multicellular organism

Question 40

The regulatory protein E2F triggers:

Answer 40

Genes required for DNA synthesis to be expressed

Question 41

When E2F is first produced, its function is blocked by the ______

Answer 41

Rb tumor suppressor | Extra Info: Rb stands for retinoblastoma, cancer of the retina [Lead to the discovery of Rb tumor suppressor]

Question 42

When E2F has an Rb bound to it E2F is ____

Answer 42

Deactivated

Question 43

As long as Rb is bound to E2F, the cell will remain in the __ phase

Answer 43

G1

Question 44

MPF permits a cell to pass from the G1 phase to the S phase by:

Answer 44

Phosphorylating Rb, which releases it from E2F

Question 45

The G1 checkpoint works by:

Answer 45

Cyclin bound to Cdk phosphorylating the Rb protein bound to E2F, thus activating E2F to prepare for the S phase

Question 46

After the G1 checkpoint is passed, Cyclin is ubiquitinated which means:

Answer 46

It is tagged for destruction so that the cell doesn't keep preparing for the S phase beyond what is necessary

Question 47

Bacteria go through _____ instead of mitosis

Answer 47

Binary fission

Question 48

During binary fission, what happens?

Answer 48

DNA copies are pulled to opposite ends of the bacteria cell, and then the cell divides. No need for any of the other steps in eukaryotes due to the nature of prokaryotes