Question

Part 7

What is a difference in the formation of leading strand and lagging strand?

• A. leading strand is formed continuously, lagging strand is formed in fragments

• B. leading strand elongates at 3’ end, lagging strand elongates at 5’ end

• C. leading strand is formed by DNA polymerase, lagging strand is formed by reverse transcriptase

• D. leading strand starts with an RNA primer, lagging strand starts itself

Which of these cells in a body are most likely to be in G0 phase (exited from cell cycle)

• A. muscle cells in the heart

• B. cancerous cells in a tumor

• C. stem cells in the skin

All cells in an adult body are genetically identical, because a fertilized egg grows into an embryo and then an adult, using the cell division known as;

• A. replication

• B. gametogenesis

• C. meiosis

• D. mitosis

The checkpoint that decides if the cell should continue to divide again, is located at;

• A. start of G2 phase

• B. end of M phase

• C. end of G1 phase

• D. end of S phase

Answer 1

1) DNA polymerase synthesizes both leading strand and lagging strand in the 5` to 3` direction, leading strand is synthesized continuously and lagging strand is synthesized as fragments called Okazaki fragments.

a) leading strand is formed continuously, lagging strand is formed in fragments

2) cells which do not undergo cell division enters into G0 phase, cancer cells divide rapidly and stem cells of the skin divides to produce new skin cells, cardiac muscle cells do not divide frequently, cardiac muscle cells divide when cells damage so the answer is a) muscle cells in the heart.

3) zygote divides mitosis to increase the cell number, mitosis is the equational division, the number of chromosomes in both parent cells and daughter cells are the same.

gametogenesis is the process of formation of gametes, meiosis occurs in germline cells to produce gametes so the answer is C) meiosis.

4) the checkpoint that determines whether the cell divides again is the checkpoint in the late G1 phase, the cell determines whether it should enter into G0 phase or G2 phase in the G1 checkpoint.

the checkpoint at the end of S phase checks whether DNA is damaged, and DNA is completely divided or not so the answer is c) end of G1 phase.