Question 1

Which statement best describes the central dogma of molecular biology?

Accepted Answer

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

Question 2

What is the role of RNA polymerase during transcription?

Accepted Answer

It synthesizes RNA according to the sequence of bases in a DNA template.

Question 3

In eukaryotic cells, where does RNA processing occur?

Accepted Answer

In the nucleus, before mRNA is exported to the cytoplasm.

Question 4

Which strand of DNA serves as the template for mRNA synthesis?

Accepted Answer

The 3' to 5' template strand.

Question 5

What is a codon?

Accepted Answer

A group of three bases in mRNA that specifies an amino acid.

Question 6

Why is the genetic code described as 'degenerate'?

Accepted Answer

Because more than one codon can specify the same amino acid.

Question 7

Given the DNA sequence 5'-ATG GGC CAA TGA CTT TCA ATA A-3', what is the corresponding mRNA sequence?

Accepted Answer

$$5'-AUG GGC CAA UGA CUU UCA AUA A-3'$$

Question 8

Which of the following best explains the relationship between genotype and phenotype?

Accepted Answer

Genotype is the DNA sequence, which is transcribed and translated into proteins that determine phenotype.

Question 9

What would happen if the reading frame of an mRNA sequence is shifted by the addition of a single nucleotide?

Accepted Answer

All subsequent codons and amino acids would change, potentially resulting in a nonfunctional protein.

Question 10

Which of the following is true about the start codon in translation?

Accepted Answer

It is AUG and codes for methionine, defining the reading frame.

Question 11

A mutation changes a codon from UUU to UUC in an mRNA sequence. What is the likely effect?

Accepted Answer

There will be no change, as both codons code for the same amino acid (phenylalanine).

Question 12

Which process occurs in the cytoplasm of eukaryotic cells?

Accepted Answer

Translation of mRNA to protein.

Question 13

What is the function of the promoter region in transcription?

Accepted Answer

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

Question 14

Which of the following statements about gene expression is correct?

Accepted Answer

Gene expression is the process by which DNA directs the synthesis of proteins.

Question 15

If a DNA template strand has the sequence 3'-TAC GGA TTT-5', what is the corresponding mRNA sequence?

Accepted Answer

$$5'-AUG CCU AAA-3'$$

Question 16

Which of the following is a consequence of the redundancy of the genetic code?

Accepted Answer

Multiple codons can specify the same amino acid.

Question 17

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

Accepted Answer

Uracil

Question 18

Which of the following best describes the 'one gene-one polypeptide' hypothesis?

Accepted Answer

Each gene codes for a single polypeptide, which may be part of a protein.

Question 19

What is the effect of a mutation that introduces a premature stop codon in the mRNA sequence?

Accepted Answer

Translation will terminate early, resulting in a truncated protein.

Question 20

Which of the following is NOT a step in the process of transcription?

Accepted Answer

Translation

Gene Expression: From DNA to Protein (Central Dogma and the Genetic Code)

Study Guide - Practice Questions