Mastering Biology Chp 9-10

Question 1

What could result from a gain-of-function mutation in a proto-oncogene?

Answer 1

abnormal stimulation of cell growth and division

Question 2

which of the following processes would result from a mutation in the ras gene?

Answer 2

activation of protein kinases

Question 3

the drug cytochalasin B blocks the function of actin. which of the following aspects of the animal cycle would be most disrupted by cytochalasin B?

Answer 3

cleavage furrow formation and cytokinesis

Question 4

a cell in G2 of the cell division cycles contains 16 chromatids. how many centromeres are present in this cell?

Answer 4

16

Question 5

what happens during G1 before the checkpoint?

Answer 5

non-dividing cells exit cell cycle

Question 6

what happens at the G1 checkpoint

Answer 6

cell commits to go through the cycle

Question 7

what happens during the S phase

Answer 7

DNA replicates

Question 8

What happens during G2

Answer 8

two centromeres have formed

Question 9

what happens during M phase

Answer 9

mitotic spindle begins to form

Question 10

What happens during the M checkpoint

Answer 10

cell divides, forming two daughter cells

Question 11

T/F crossing over prevents homologous chromosomes from separating during meiosis 1

Answer 11

False

Question 12

T/F as a result of crossing over, sister chromatids are no longer identical to eachother

Answer 12

True

Question 13

Crossing over occurs at the ends of chromosomes rather than near the centromeres

Answer 13

true

Question 14

For crossing over to occur, homologous chromosomes must align precisely early in prophase 1 so that nonsister chromatids can exchange corresponding segments of DNA

Answer 14

True