Question 1

Which nitrogenous base is a purine that pairs with cytosine and is found in both DNA and RNA?

Accepted Answer

Guanine (G)

Question 2

Which nitrogenous base is found only in RNA and pairs with adenine?

Accepted Answer

Uracil (U)

Question 3

Which of the following statements about nitrogenous bases is correct?

Accepted Answer

Uracil is a pyrimidine found only in RNA.

Question 4

Which base pairing is unique to DNA and does not occur in RNA?

Accepted Answer

Adenine (A) – Thymine (T)

Question 5

Which nitrogenous base is a pyrimidine that pairs with guanine and is found in both DNA and RNA?

Accepted Answer

Cytosine (C)

Question 6

A mutation replaces a thymine in DNA with a uracil. What is the most likely effect on the molecule?

Accepted Answer

The DNA will pair uracil with adenine, mimicking RNA structure.

Question 7

Which of the following correctly matches the nitrogenous base with its family and pairing partner?

Accepted Answer

Guanine (G) – Purine – pairs with Cytosine (C)

Question 8

Which base is a pyrimidine found only in DNA?

Accepted Answer

Thymine (T)

Question 9

If a DNA strand has the sequence 5'-ATCG-3', what is the complementary RNA sequence transcribed from it?

Accepted Answer

5'-UAGC-3'

Question 10

Which of the following statements best explains why uracil is not found in DNA?

Accepted Answer

Uracil is chemically unstable in the double helix structure of DNA.

Question 11

Which of the following base pairs is correct for RNA but not for DNA?

Accepted Answer

Adenine (A) – Uracil (U)

Question 12

Which nitrogenous base is a purine and is found in both DNA and RNA?

Accepted Answer

Adenine (A)

Question 13

A scientist isolates a nucleic acid and finds it contains uracil. Which conclusion is most accurate?

Accepted Answer

The nucleic acid is definitely RNA.

Question 14

Which of the following is a correct statement about the families of nitrogenous bases?

Accepted Answer

Adenine and guanine are purines.

Question 15

Which base pairing is found in both DNA and RNA molecules?

Accepted Answer

Guanine (G) – Cytosine (C)

Genetics: Structure, Function, and Variation of Genetic Material

Study Guide - Practice Questions