Question 1

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

Accepted Answer

The unidirectional flow of genetic information from DNA to RNA to protein.

Question 2

During transcription, which enzyme is responsible for synthesizing RNA from a DNA template?

Accepted Answer

RNA polymerase

Question 3

A DNA template strand has the sequence 3'-TACGGTACG-5'. What is the sequence of the corresponding mRNA transcript?

Accepted Answer

5'-AUGCCAUGC-3'

Question 4

Which of the following modifications occur to eukaryotic pre-mRNA before it becomes mature mRNA?

Accepted Answer

Addition of a 5' cap and a poly-A tail

Question 5

What is the function of introns in eukaryotic genes?

Accepted Answer

They are noncoding regions that are removed during RNA splicing.

Question 6

Which type of RNA carries amino acids to the ribosome during translation?

Accepted Answer

tRNA

Question 7

Given the mRNA sequence 5'-AUGUUUCGUUGA-3', what is the resulting amino acid sequence? (Use the genetic code)

Accepted Answer

Met-Phe-Arg-Stop

Question 8

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

Accepted Answer

It is redundant, meaning multiple codons can code for the same amino acid.

Question 9

A mutation changes the DNA sequence from 5'-ATG GAA TGA-3' to 5'-ATG GAA TGG-3'. What type of mutation is this?

Accepted Answer

Missense mutation

Question 10

Which of the following events occurs during the elongation phase of translation?

Accepted Answer

Amino acids are added one by one to the C-terminus of the growing polypeptide chain.

Question 11

Which of the following is a possible consequence of a frameshift mutation?

Accepted Answer

A completely different amino acid sequence downstream of the mutation

Question 12

What is the role of the spliceosome in eukaryotic cells?

Accepted Answer

It removes introns from pre-mRNA.

Question 13

Which of the following best explains why a single base substitution may be silent?

Accepted Answer

The new codon codes for the same amino acid due to redundancy in the genetic code.

Question 14

Which of the following post-translational modifications is reversible and can activate or deactivate a protein?

Accepted Answer

Phosphorylation

Question 15

A ribosome has three tRNA binding sites. Which answer matches the tRNA binding site with the correct function?

Accepted Answer

A-site: holds the tRNA with the next amino acid; P-site: holds the growing polypeptide chain; E-site: exit site for discharged tRNA.

Question 16

Which of the following is true regarding the direction of ribosome movement during translation?

Accepted Answer

The ribosome moves along the mRNA in the 5' to 3' direction.

Question 17

Which of the following processes is the first event to take place in translation?

Accepted Answer

The small subunit of the ribosome recognizes and attaches to the mRNA.

Question 18

A particular triplet of bases in the template strand of DNA is 5′-AGT-3′. What would be the corresponding codon for the mRNA that is transcribed?

Accepted Answer

3′-UCA-5′

Question 19

Which of the following mutations is most likely to have the most serious effects on the polypeptide product if it occurs just after the start codon in the mRNA?

Accepted Answer

Deletion of one nucleotide

Gene Expression: From Gene to Protein (Ch. 14) – Study Notes

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