Chapter 16 30 questions

Which combination correctly identifies the components of a DNA nucleotide?

Deoxyribose, phosphate, and a nitrogenous base

Where is genetic information stored in a DNA molecule?

In the sequence of nitrogenous bases

Which strand is complementary to 5′–ATGCCA–3′ when written directly beneath it?

3′–TACGGT–5′

After one round of semiconservative DNA replication, each daughter DNA molecule contains:

One parental strand and one newly synthesized strand

Which enzyme separates the parental DNA strands at the replication fork?

Helicase

What is the primary function of topoisomerase during DNA replication?

To relieve torsional strain ahead of the replication fork

Why is an RNA primer necessary for DNA synthesis?

It provides a free 3′-OH that DNA polymerase can extend.

Which statement correctly compares the leading and lagging strands?

The leading strand is synthesized continuously, while the lagging strand is synthesized in fragments.

Which enzyme removes RNA primers and replaces them with DNA?

DNA polymerase I

If DNA ligase is inactive, which step would be directly impaired?

Sealing breaks in the DNA backbone between adjacent fragments

True or False: A DNA nucleotide contains a phosphate group, deoxyribose, and a nitrogenous base.

True

True or False: The two strands of the DNA double helix run in the same 5′-to-3′ direction.

False

True or False: In prokaryotic cells, chromosomal DNA is located in the nucleoid region.

True

True or False: During semiconservative replication, both parental strands remain together in one daughter DNA molecule.

False

True or False: Single-strand binding proteins help prevent separated DNA strands from reannealing.

True

True or False: DNA polymerase can begin synthesizing a new DNA strand without a primer.

False

True or False: Both leading and lagging strands are synthesized in the 5′-to-3′ direction.

True

True or False: Okazaki fragments are short DNA segments formed during leading-strand synthesis.

False

True or False: DNA ligase replaces RNA primers with DNA nucleotides.

False

True or False: Proofreading helps improve the accuracy of DNA replication.

True

In DNA, adenine pairs with ____, while guanine pairs with ____.

Thymine, cytosine

The opposite orientation of the two DNA strands is described as ____.

Antiparallel

The sites where DNA replication begins are called ____.

Origins of replication

The Y-shaped region where parental DNA strands separate and new strands are synthesized is called a replication ____.

Fork

The enzyme that separates parental DNA strands is ____.

Helicase

The enzyme that synthesizes a short RNA primer is ____.

Primase

DNA polymerase adds nucleotides to the free ____ group at the end of a growing strand.

3′-OH

The ____ strand is synthesized continuously in the same overall direction as replication fork movement.

Leading

The short DNA segments produced during lagging-strand synthesis are called ____ fragments.

Okazaki

The enzyme that seals breaks in the sugar–phosphate backbone between adjacent DNA fragments is ____.

DNA ligase