14. DNA Replication

During DNA replication, the enzyme ___________, catalyzes the elongation of new DNA by adding, to the 3' end of the previous nucleotide, new nucleotides that are complementary to a DNA template.

Which of the following enzymes breaks the hydrogen bonds between the DNA strands?

Which of the following enzyme-function matches is incorrect?

Which of the following enzymes is responsible for removing RNA primers and replacing them with DNA?

Indicate the true statements and then correct the false statements so that they are true.

a. DNA is replicated in a 3' to 5' direction.

b. DNA has a parallel arrangement.

c. RNA primase is required on the leading and the lagging strand.

d. DNA ligase forms phosphodiester bonds between Okazaki fragments on the lagging strand.

e. Prokaryotic mRNA requires processing before it is translated.

f. In RNA, A bonds to U.

g. In DNA, C bonds with G.

h. RNA contains deoxyribonucleotides.

The following is a schematic of the parent DNA that is about to be repli­cated. Which side of the pictured DNA molecule (A or B) would be the leading side? Explain your answer.

Select the false statement:

a. DNA is made of deoxyribonucleotides.

b. RNA is made of ribonucleotides.

c. RNA is built in a 5' to 3' direction.

d. DNA is built in a 5' to 3' direction.

e. RNA primase builds RNA in transcription.

Match the following:

Which of the following molecules functions as a “proofreader” for a newly replicated strand of DNA?

a. DNA polymerase III

b. Primase

c. Helicase

d. Ligase

The addition of a ----CH₃ to a cytosine nucleotide after DNA replication is called: .

a. Methylation

b. Restriction

c. Transcription

d. Transversion

Ligase plays a major role in:

a. Replication of lagging strands

b. mRNA processing in eukaryotes

c. Polypeptide synthesis by ribosomes

d. RNA transcription

On the accompanying figure, label:

DNA polymerase I, DNA polymerase III, helicase, lagging strand, leading strand, ligase, nucleotide (triphosphate), Okazaki fragment, primase, replication fork, RNA primer, and stabilizing proteins.