Question 1

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

Accepted Answer

Information flows from DNA to RNA to protein.

Question 2

During transcription, which DNA strand is used as the template for mRNA synthesis, and in which direction is the mRNA synthesized?

Accepted Answer

The template strand; mRNA is synthesized 5' to 3'.

Question 3

A segment of DNA has the following sequence on the template strand: 3'-TACGGTACG-5'. What is the corresponding mRNA sequence produced during transcription?

Accepted Answer

$$5'	ext{AUGCCAUGC}3'$$

Question 4

Which of the following statements about promoters is correct?

Accepted Answer

Promoters are specific DNA sequences where RNA polymerase binds to initiate transcription.

Question 5

What is the primary function of the 5' cap added during eukaryotic mRNA processing?

Accepted Answer

It protects mRNA from degradation and helps initiate translation.

Question 6

Which of the following best explains why eukaryotic mRNA is often shorter than the DNA region from which it was transcribed?

Accepted Answer

Introns are removed during RNA processing.

Question 7

A mutation changes a codon from UAU (tyrosine) to UAA (stop codon). What type of mutation is this, and what is its likely effect on the protein?

Accepted Answer

Nonsense mutation; results in premature termination of translation.

Question 8

Which of the following is a key difference between gene expression in prokaryotes and eukaryotes?

Accepted Answer

Eukaryotes process pre-mRNA in the nucleus before translation.

Question 9

Which of the following best describes the role of tRNA during translation?

Accepted Answer

tRNA carries amino acids to the ribosome and matches its anticodon to the mRNA codon.

Question 10

Alternative splicing allows a single gene to:

Accepted Answer

Code for multiple proteins by including or excluding different exons.

Question 11

A scientist discovers a mutation that does not change the amino acid sequence of the resulting protein. What type of mutation is this?

Accepted Answer

Silent mutation

Question 12

Which of the following is true regarding the directionality of nucleic acid synthesis during transcription?

Accepted Answer

RNA is synthesized in the 5' to 3' direction.

Question 13

Which of the following best describes the function of the poly-A tail added to eukaryotic mRNA?

Accepted Answer

It increases mRNA stability and prevents degradation.

Question 14

A frameshift mutation is most likely to result from:

Accepted Answer

An insertion or deletion of nucleotides not in multiples of three.

Question 15

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

Accepted Answer

Exons are coding regions that remain in mature mRNA.

Question 16

If the coding strand of DNA has the sequence 5'-ATGCGT-3', what is the sequence of the mRNA produced?

Accepted Answer

$$5'	ext{AUGCGU}3'$$

Question 17

Which of the following is a function of RNA polymerase during transcription?

Accepted Answer

It unwinds the DNA double helix and synthesizes mRNA.

Question 18

Which of the following best explains why a mutation in the promoter region of a gene might prevent gene expression?

Accepted Answer

The mutation could prevent RNA polymerase from binding, blocking transcription initiation.

Question 19

Which of the following is true about housekeeping genes?

Accepted Answer

They are expressed at all times in all cells to maintain basic cellular function.

Question 20

A patient has a genetic disorder caused by a single nucleotide insertion in a gene. What is the most likely effect at the protein level?

Accepted Answer

A frameshift mutation, leading to a completely altered amino acid sequence downstream.

Gene Expression and the Central Dogma: Study Notes for General Biology

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