11. Cell Division

After S phase, what makes up a single chromosome?

a. Two daughter chromosomes

b. A double-stranded DNA molecule

c. Two single-stranded DNA molecules

d. Two sister chromatids

It is difficult to observe individual chromosomes during interphase because

a. The DNA has not been replicated yet

b. They are in the form of long, thin strands

c. They leave the nucleus and are dispersed to other parts of the cell

d. Homologous chromosomes do not pair up until division starts

Which of the following occurs during S phase?

a. Condensation of the chromosomes

b. Replication of the DNA

c. Separation of sister chromatids

d. Spindle formation

Cell A has half as much DNA as cells B, C, and D in a mitotically active tissue. Cell A is most likely in

a. G1

b. G2

c. Prophase

d. Metaphase

A biochemist measured the amount of DNA in cells growing in the laboratory and found that the quantity of DNA in a cell doubled

a. Between prophase and anaphase of mitosis

b. Between the G1 and G2 phases of the cell cycle

c. During the M phase of the cell cycle

d. Between prophase I and prophase II of meiosis

A particular cell type spends 4 hours in G1 phase, 2 hours in S-phase, 2 hours in G2 phase, and 30 minutes in M-phase. If a pulse-chase experiment were performed with radioactive thymidine on an asynchronous culture of such cells, what percentage of mitotic cells would be radiolabeled 9 hours after the pulse?

a. 0 percent

b. 50 percent

c. 75 percent

d. 100 percent

If a cell at G₁ contains four picograms of DNA, how many picograms of DNA will it contain at the end of the S phase of the cell cycle?

a. 0

b. 2

c. 4

d. 8