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DP IB Biology: HL

Topic Questions

Home / IB / Biology: HL / DP / Topic Questions / 2. Molecular Biology / 2.5 Nucleic Acids: Structure & DNA Replication / Multiple Choice: Paper 1


2.5 Nucleic Acids: Structure & DNA Replication

Question 1

Marks: 1

Which of the following would be the result of analysing a DNA molecule 14 000 base pairs in length?

  • 28 000 pentose sugars, 14 000 phosphate groups, an equal ratio of cytosine to thymine bases and an equal ratio of guanine to adenine bases

  • 28 000 pentose sugars, 28 000 phosphate groups, an equal ratio of cytosine to guanine bases and an equal ratio of thymine to adenine bases

  • 14 000 pentose sugars, 28 000 phosphate groups, an equal ratio of cytosine to thymine bases and an equal ratio of guanine to adenine bases

  • 28 000 pentose sugars, 28 000 phosphate groups, an equal ratio of cytosine to thymine bases and an equal ratio of guanine to adenine bases

Choose your answer
  

Question 2

Marks: 1

Which of the following would not be considered an advantage of complementary base pairing in DNA?

  • It enables each DNA strand to act as a template for the formation of a new strand during replication

  • Hydrogen bonding between complementary bases stabilises the structure of the DNA molecule

  • It ensures genetic continuity between generations of cells so that they all contain the same genetic information as the parent cells

  • It plays an important role in maintaining the covalent bonds within the DNA molecule

Choose your answer
  

Question 3

Marks: 1

Which of the rows in the following table correctly identifies the function of each enzyme listed?

  Helicase RNA polymerase DNA polymerase
A. Breaks the hydrogen bonds between complementary DNA bases Links thymine to the adjacent nucleotide through covalent bonds Binds to a template DNA strand and pairs uracil up with adenine
B. Responsible for the formation of hydrogen bonds between complementary DNA bases Binds to a template DNA strand and pairs uracil up with adenine Links thymine to the adjacent nucleotide through covalent bonds
C. Breaks the hydrogen bonds between complementary DNA bases Binds to a template DNA strand and pairs uracil up with adenine Links thymine to the adjacent nucleotide through covalent bonds
D. Binds to a template DNA strand and pairs uracil up with adenine Links thymine to the adjacent nucleotide through covalent bonds Responsible for the formation of hydrogen bonds between complementary DNA bases
    Choose your answer
      

    Question 4

    Marks: 1

    The following events occur in the process of DNA replication.

    1. Complementary strands are separated
    2. Free DNA nucleotides pair with complementary nucleotides on each template strand
    3. Hydrogen bonds are formed between complementary bases
    4. Hydrogen bonds are broken between complementary bases
    5. Covalent bonds form between the pentose sugar and the phosphate group of adjacent nucleotides

    Which of the following is the correct order of the events?

    • 1 → 3 → 4 → 2 → 5

    • 3 → 1 → 2 → 4 → 5

    • 2 → 1 → 3 → 4 → 5

    • 4 → 1 → 2 → 3 → 5

    Choose your answer
      

    Question 5

    Marks: 1

    The experiments done by Meselson and Stahl in the 1950s provided evidence that DNA replication was semi-conservative.

    They transferred bacteria that contained only 15N in their DNA and transferred them to a medium containing only 14N. They allowed the bacteria to divide twice and then centrifuged the DNA.

    The following diagram shows a few test tubes with results from their investigation.

    7bbtfHYK_h-5

    Which of these test tubes shows the predicted results after two generations in the medium with the light isotope?

      Choose your answer