Question 1

Which of the following statements correctly describes the difference between DNA and RNA?

Accepted Answer

DNA is found in chromosomes and acts as the carrier of genetic information, while RNA is not found in chromosomes and serves as an intermediate in gene expression.

Question 2

What is the chemical linkage between monomer units in nucleic acids called?

Accepted Answer

Phosphodiester bond

Question 3

According to Chargaff's rules, which of the following is true for double-stranded DNA?

Accepted Answer

The amount of adenine equals the amount of thymine, and the amount of guanine equals the amount of cytosine.

Question 4

Which feature of the DNA double helix is essential for its function in genetic information storage?

Accepted Answer

The two polynucleotide chains are antiparallel and held together by hydrogen bonds between bases.

Question 5

During transcription, which DNA strand serves as the template for mRNA synthesis?

Accepted Answer

The antisense (template) strand

Question 6

Given the DNA template strand sequence $$5'	ext{TCGAATTCCGAAT}3'$$, what is the corresponding mRNA sequence (in the $$5'ightarrow 3'$$ direction)?

Accepted Answer

$$5'	ext{AGCUUAAGGCUUA}3'$$

Question 7

Which of the following best describes the central dogma of molecular biology?

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Question 8

Which type of RNA acts as an adaptor between mRNA and amino acids during translation?

Accepted Answer

tRNA

Question 9

A mutation changes a codon from $$	ext{GAG} ($$glutamate) to $$	ext{GTG} ($$valine) in the hemoglobin gene. What type of mutation is this, and what disease can it cause?

Accepted Answer

Missense mutation; sickle cell anemia

Question 10

Which of the following codons is the start codon for translation in eukaryotes?

Accepted Answer

$$	ext{AUG}$$

Question 11

What is the consequence of a nonsense mutation in a protein-coding gene?

Accepted Answer

It introduces a premature stop codon, leading to truncated protein synthesis.

Question 12

Which of the following statements about the genetic code is correct?

Accepted Answer

The genetic code is degenerate, meaning some amino acids are encoded by more than one codon.

Question 13

A frameshift mutation is most likely to result from which of the following?

Accepted Answer

A deletion or insertion of one or two nucleotides

Question 14

Which of the following is NOT a function of DNA in the cell?

Accepted Answer

Catalyzing chemical reactions in the cytoplasm

Question 15

Which of the following RNA types is directly involved in the formation of ribosomes?

Accepted Answer

rRNA

Question 16

If the mRNA sequence is $$5'	ext{AUGGCCUAA}3'$$, what is the corresponding amino acid sequence?

Accepted Answer

Met-Ala-Stop

Question 17

Which of the following best explains why not all base substitutions result in a change in the encoded amino acid?

Accepted Answer

The genetic code is degenerate, allowing multiple codons to encode the same amino acid.

Question 18

Which of the following is a stop codon in the genetic code?

Accepted Answer

$$	ext{UAA}$$

Question 19

A patient has a mutation that causes the insertion of a single nucleotide into the coding region of a gene. What is the most likely outcome?

Accepted Answer

A frameshift mutation altering all downstream amino acids

Question 20

Which of the following best describes the role of mRNA in the cell?

Accepted Answer

It encodes the sequence of amino acids in a protein.

Nucleic Acids and the Genetic Code: Structure, Function, and Mutations

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