Question 1

Which statement best describes the 'Central Dogma of Molecular Biology'?

Accepted Answer

Genetic information flows from DNA to RNA to protein.

Question 2

During DNA replication, what does 'semi-conservative' mean?

Accepted Answer

Each new DNA molecule contains one parental strand and one newly synthesized strand.

Question 3

Given a DNA strand with the sequence 5'-GTACCCTA-3', what is the complementary DNA strand?

Accepted Answer

3'-CATGGGAT-5'

Question 4

Which enzyme is responsible for unwinding the DNA double helix during replication?

Accepted Answer

Helicase

Question 5

In eukaryotic cells, which modification is added to the 3' end of mRNA to increase its stability?

Accepted Answer

Poly-A tail

Question 6

During transcription, which base in RNA pairs with adenine in DNA?

Accepted Answer

Uracil

Question 7

What is the function of tRNA during translation?

Accepted Answer

It brings amino acids to the ribosome and matches them to the mRNA codon via its anticodon.

Question 8

Which property of the genetic code helps protect against mutations in the third base of a codon?

Accepted Answer

Conservativeness

Question 9

If a DNA template strand reads 3'-TACGGTACG-5', what is the sequence of the mRNA produced during transcription?

Accepted Answer

5'-AUGCCAUGC-3'

Question 10

Which of the following best explains why bacterial mRNA can be translated immediately after transcription, but eukaryotic mRNA cannot?

Accepted Answer

Eukaryotic mRNA requires processing such as splicing and addition of a 5' cap and poly-A tail.

Question 11

Which of the following is true about Okazaki fragments?

Accepted Answer

They are short DNA fragments synthesized on the lagging strand.

Question 12

A mutation changes the DNA sequence from 5'-ATG-3' to 5'-ATA-3'. What is the most likely effect on the protein produced?

Accepted Answer

The amino acid sequence may change, potentially altering the protein's function.

Question 13

Which process involves the removal of introns from pre-mRNA?

Accepted Answer

Splicing

Question 14

What is the role of the promoter region in transcription?

Accepted Answer

It is the site where RNA polymerase binds to initiate transcription.

Question 15

Which of the following best describes the relationship between genotype and phenotype as shown in the Central Dogma?

Accepted Answer

Genotype (DNA sequence) determines mRNA and protein sequence, which results in phenotype.

Question 16

Which of the following codons is a stop codon in translation?

Accepted Answer

$$\mathrm{UAA}$$

Question 17

During translation, what is the function of the ribosome?

Accepted Answer

It catalyzes the formation of peptide bonds between amino acids.

Question 18

Which of the following is NOT a property of the genetic code?

Accepted Answer

Ambiguous

Question 19

A DNA template strand reads 3'-TAC-5'. What amino acid will be added first during translation?

Accepted Answer

Methionine

Question 20

Which of the following best explains why mutations in the third base of a codon often do not change the amino acid sequence?

Accepted Answer

The genetic code is redundant and conservative, so many amino acids are coded by multiple codons differing in the third base.

Molecular Biology of the Gene: DNA Replication, Transcription, and Translation

Study Guide - Practice Questions