Chapter 16 30 questions

  1. VWhich combination correctly identifies the components of a DNA nucleotide?
    B. Deoxyribose, phosphate, and a nitrogenous base

  2. Where is genetic information stored in a DNA molecule?
    A. In the sequence of nitrogenous bases

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

  4. After one round of semiconservative DNA replication, each daughter DNA molecule contains:
    D. One parental strand and one newly synthesized strand

  5. Which enzyme separates the parental DNA strands at the replication fork?
    A. Helicase

  6. What is the primary function of topoisomerase during DNA replication?
    B. To relieve torsional strain ahead of the replication fork

  7. Why is an RNA primer necessary for DNA synthesis?
    C. It provides a free 3′-OH that DNA polymerase can extend.

  8. Which statement correctly compares the leading and lagging strands?
    D. The leading strand is synthesized continuously, while the lagging strand is synthesized in fragments.

  9. In the bacterial replication model presented in the slides, which enzyme removes RNA primers and replaces them with DNA?
    A. DNA polymerase I

  10. If DNA ligase is inactive, which step would be directly impaired?
    B. Sealing breaks in the DNA backbone between adjacent fragments

Part II. True or False

Write True or False.

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

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

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

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

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

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

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

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

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

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

Part IV. Fill in the Blank

Write the correct term or phrase in each blank.

  1. In DNA, adenine pairs with , while guanine pairs with .
    thymine, cytosine

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

  3. The sites where DNA replication begins are called .
    origins of replication

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

  5. The enzyme that separates parental DNA strands is .
    helicase

  6. The enzyme that synthesizes a short RNA primer is .
    primase

  7. DNA polymerase adds nucleotides to the free group at the end of a growing strand.
    3′-OH

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

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

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