DNA, Cell Division, Genes

Question 1

What is Mitosis

Answer 1

A form of cell division with produces two daughter cells, genetically identical to each other and the mother cell

Question 2

What is Meiosis

Answer 2

A form of cell division which produces four genetically unique daughter cells with half the ploidy of the mother cells

Question 3

What is the function of crossing over?

Answer 3

The exchange of identical regions of homologous chromosomes during Prophase 1

Question 4

What is the function of independent assortement

Answer 4

when tetrads line up in the middle of the cell in a random order. Occurs during Metaphase 1

Question 5

What happens with spindle fibers?

Answer 5

spindle fibers separate chromosomes during Anaphase 1 and Anaphase 2. They are less likely to malfunction

Question 6

Egg formation

Answer 6

cells which will become eggs start meiosis when the organism is still a fetus and then become paused before Metaphase 1. Spindle Fibers is as old as human females age

Question 7

When is non-disjunction more likely in females?

Answer 7

During Anaphase 1

Question 8

When is non-disjunction more likely in males?

Answer 8

During Anaphase 1 and Anaphase 2

Question 9

What is a proto-oncogene?

Answer 9

it initiated or speeds up the rate of cell division

Question 10

What is a tumor-suppressor gene?

Answer 10

A gene that inhibits or slows down the rate of cell division

Question 11

What can mutation of genes lead to?

Answer 11

Oncogenes (Cancer -causing genes)

Question 12

What is p53?

Answer 12

the protein p53 activates genes that stop the cell cycle. It is classified as a tumor-suppressor gene

Question 13

What is apoptosis?

Answer 13

Pre-programmed cell death

Question 14

What is E2F?

Answer 14

produced by proto-oncogenes, promoting cell division

Question 15

What is Rb?

Answer 15

produced by tumor suppressor genes, inhibit cell division

Question 16

How does the G1 checkpoint operate?

Answer 16

1. Growth factor arrives from other cells
2. Growth factors cause the increas ein the cyclin and E2F concentrations.
3. Cyclins bind to the CdK, cdK is phosphorylated. Rb inactivates E2F when binding to it
4. Cdk is activated by dephosphorylation. it catalyzed phosphorylation of Rb
5. Rb releases E2F
6. E2F enters nucleus and triggers production of S-phase proteins

Question 17

What are G2 cyclins and CDK?

Answer 17

As the cell progresses through the cell cycle, the concentration of G2 Cyclins increase. CDK levels remain constant. When the concentration of G2 cyclins becomes great enough, they bind with CDKs, forming a complex called MPF.

Question 18

What does MPF do?

Answer 18

1. initiates mitosis
2. destroys G2 Cyclins

Question 19

What is contact inhibition?

Answer 19

a process that causes cells to stop dividing if they are in physical contact with other cells. It prevents cells from overcrowding

Question 20

What is anchorage dependence?

Answer 20

allows cells to divide if they are anchored to other cells. prevents cells knocked loose.

Question 21

Describe the Hershey- Chase Experiment

Answer 21

it demonstrated that DNA, not protein was the molecule of heredity as in the experiment that was done the colonies infected with radiolabeled DNA had much more radioactivity.

Question 22

The product of meiosis is:
A. Two genetically identical daughter cells
B. Two genetically unique daughter cells
C. Four genetically identical daughter cells
D. Four genetically unique daughter cells

Answer 22

Four genetically unique daughter cells

Question 23

During what phase of meiosis to sister chromatids separate?

Answer 23

Anaphase II

Question 24

3. When does crossing over occur?

Answer 24

Prophase I

Question 25

When is a non-disjunction most likely to occur during egg formation?

Answer 25

Anaphase I

Question 26

What happens to a cell which does not pass the G1 checkpoint? A. It dies via apoptosis B. It enters the S phase of the cell cycle C. It enters the G0 phase of the cell cycle D. It enters the G2 phase of the cell cycle

Answer 26

It enters the G0 phase of the cell cycle

Question 27

When is a non-disjunction most likely to occur during sperm formation?

Answer 27

Anaphase I & II are equally as likely

Question 28

The gene which produces E2F is classified as a

Answer 28

Proto-oncogene

Question 29

The decline of MPF activity at the end of mitosis is due to

Answer 29

The degradation of G2 cyclins

Question 30

The gene which produces p53 is classified as a(n)

Answer 30

Tumor suppressor gene

Question 31

The genes which regulate contact inhibition are classified as:

Answer 31

Tumor suppressor genes

Question 32

MPF is composed of what?

Answer 32

Aggregations of G2 cyclins and CDKs

Question 33

. A cell lining an artery is knocked loose and is now floating free. However, it will not divide. What is preventing this free floating cell from dividing?

Answer 33

Anchorage dependence

Question 34

A cell has very damaged DNA, and will not divide. What prevents this cell from dividing? A. p53 activity B. Contact inhibition C. Anchorage dependence D. Telomerase activity E. None of the above

Answer 34

p53 activity

Question 35

Is DNA semi-conservative, conservative, or dispersive

Answer 35

semi-conservative

Question 36

Helicase

Answer 36

unwinds DNA double helix

Question 37

Topisomerase

Answer 37

removes supercoils

Question 38

Primase

Answer 38

creates short RNA primers

Question 39

DNA pol III

Answer 39

performs the majority of the DNA replication

Question 40

DNA pol I

Answer 40

removes primers and replaces them with DNA

Question 41

Ligase

Answer 41

used after DNA pol I removes the primer and joins the two Okazaki fragments

Question 42

How is all DNA synthesized

Answer 42

it is synthesized 5' to 3'

Question 43

What are Okazaki fregments?

Answer 43

short pieces of DNA created in the lagging strand

Question 44

What is the function of DNA pol I

Answer 44

primers are removed and replaced with by DNA pol1

Question 45

What does Primase do?

Answer 45

Primase lays down a primer

Question 46

What does DNA pol III do?

Answer 46

DNA pol III synthesizes DNA all around the loop until it circles around the prime again.