BIOLOGY Chapter 12

Which of the following statements about the strands of a newly replicated DNA molecule is correct? A) Both strands contain some nucleotides from the original molecule. B) The sugar-phosphate chains are conserved and new bases are inserted between them. C) One strand is new and the other is from the original molecule. D) One strand is new and the other is from the original molecule. Both strands are made up of newly assembled nucleotides. E) The base pairs are conserved and new sugar-phosphate backbones are built up on them.

C

What is the result of DNA ligase's action?

DNA fragments are joined together.

_____ requires both a template and a free 3′ end to elongate a nucleotide chain.

DNA polymerase

T or F: During DNA replication, the leading strand contains Okazaki fragments.

False only found on lagging strand

____ moves outward from the origin of replication and breaks hydrogen bonds between DNA nucleotides.

Helicase

A eukaryotic chromosome has _____ origin(s) of replication, and a bacterial chromosome has ______ origin(s) of replication.

Many; One

_____ is the first enzyme to synthesize a nucleic acid at a replication fork.

RNA primase

____ relieves the tension on the double helix during DNA replication.

Topoisomerase

Synthesis of nucleic acids always occurs in the 5′ → 3′ direction.

True

The following enzymes play important roles in DNA replication: DNA polymerase, primase, ligase, helicase. In what order do they work during replication?

helicase, primase, DNA polymerase, ligase

What is the function of the enzyme DNA polymerase?

to synthesize a strand of DNA using DNA as a template