Question 1

Which of the following best describes the 'Central Dogma' of molecular biology?

Accepted Answer

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

Question 2

During transcription in eukaryotes, what is the role of the promoter region?

Accepted Answer

It is the DNA sequence where RNA polymerase and transcription factors bind to initiate transcription.

Question 3

Which of the following modifications occurs to eukaryotic pre-mRNA before it exits the nucleus?

Accepted Answer

Addition of a 5' cap and a poly-A tail, and removal of introns.

Question 4

A mutation changes a single base in a gene, resulting in a different amino acid in the protein product. What type of mutation is this?

Accepted Answer

Missense mutation

Question 5

Which enzyme is responsible for synthesizing RNA during transcription?

Accepted Answer

RNA polymerase

Question 6

What is the function of the spliceosome during RNA processing?

Accepted Answer

It removes introns from the pre-mRNA and joins exons together.

Question 7

Which of the following statements about introns and exons is correct?

Accepted Answer

Introns are non-coding sequences that are removed during RNA processing.

Question 8

A researcher discovers a mutation in the promoter region of a gene. What is the most likely effect of this mutation?

Accepted Answer

It will prevent the gene from being transcribed efficiently.

Question 9

Which of the following best explains why a change in DNA sequence can lead to a dramatic change in phenotype?

Accepted Answer

Because the sequence of DNA determines the sequence of amino acids in proteins, which affects protein function.

Question 10

Which of the following is NOT a step in eukaryotic RNA processing?

Accepted Answer

Removal of exons

Question 11

In the context of gene expression, what is a 'start codon' and what is its sequence in mRNA?

Accepted Answer

A codon that signals the start of translation; AUG

Question 12

Which of the following best describes the difference between prokaryotic and eukaryotic gene expression?

Accepted Answer

In eukaryotes, the mRNA is processed and must exit the nucleus before translation, while in prokaryotes, transcription and translation can occur simultaneously.

Question 13

A patient has a genetic disorder caused by a mutation that introduces a premature stop codon in the coding sequence of a gene. What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 14

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

Accepted Answer

The reading frame of the mRNA is altered, potentially changing every amino acid downstream.

Question 15

Which of the following best explains why only about 1.5% of the human genome codes for proteins?

Accepted Answer

The majority of the genome is made up of introns, spacer DNA, and genes encoding RNA products.

Question 16

Which of the following is the correct sequence of events in eukaryotic gene expression?

Accepted Answer

Transcription → RNA processing → Translation

Question 17

A scientist is studying a gene with a mutation in the TATA box. What is the most likely effect of this mutation?

Accepted Answer

The gene will not be properly transcribed because the transcription initiation complex cannot form.

Question 18

Which of the following best describes the function of the poly-A tail added during RNA processing?

Accepted Answer

It protects the mRNA from degradation and assists in export from the nucleus.

Question 19

Which of the following statements about RNA polymerase is correct?

Accepted Answer

RNA polymerase synthesizes RNA in the 5' to 3' direction using a DNA template.

Question 20

A mutation in a gene results in the removal of a single nucleotide from the coding sequence. What is the most likely effect on the protein product?

Accepted Answer

The reading frame will shift, altering the amino acid sequence downstream of the mutation.

Gene Expression: From Gene to Protein – Study Notes

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