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

$$\text{DNA} \rightarrow \text{RNA} \rightarrow \text{Protein}$$

Question 1

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

Accepted Answer

$$	ext{DNA} ightarrow 	ext{RNA} ightarrow 	ext{Protein}$$

Question 2

A mutation changes a codon from UAU to UAA in the coding region of a gene. What is the most likely effect on the resulting protein?

Accepted Answer

The protein will be truncated because UAA is a stop codon, leading to premature termination.

Question 3

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

Accepted Answer

The genetic code is redundant; multiple codons can specify the same amino acid.

Question 4

In eukaryotic cells, what is the function of the 5' cap and poly-A tail added to pre-mRNA during RNA processing?

Accepted Answer

They facilitate the export of mRNA from the nucleus, protect mRNA from degradation, and help ribosomes attach to the 5' end.

Question 5

Which enzyme is responsible for catalyzing the synthesis of RNA from a DNA template during transcription?

Accepted Answer

RNA polymerase

Question 6

A scientist introduces a gene from a jellyfish into a mosquito larva, resulting in the larva expressing a fluorescent protein. What does this experiment demonstrate about the genetic code?

Accepted Answer

The genetic code is universal, allowing genes from one organism to be expressed in another.

Question 7

Which of the following best explains why a frameshift mutation often has a more severe effect on protein function than a missense mutation?

Accepted Answer

Frameshift mutations alter the reading frame, changing all downstream amino acids.

Question 8

During translation, what is the role of tRNA?

Accepted Answer

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

Question 9

Which of the following is true regarding the difference between prokaryotic and eukaryotic gene expression?

Accepted Answer

In eukaryotes, transcription and translation are separated by the nuclear envelope.

Question 10

A mutation in the promoter region of a gene most likely affects which stage of gene expression?

Accepted Answer

Initiation of transcription

Question 11

Which of the following best describes alternative RNA splicing?

Accepted Answer

It allows a single gene to code for multiple polypeptides by including or excluding different exons.

Question 12

What is the function of the signal peptide in protein synthesis?

Accepted Answer

It directs the ribosome to the endoplasmic reticulum for proteins destined for secretion or the endomembrane system.

Question 13

Which of the following is a property of ribozymes?

Accepted Answer

They are RNA molecules with catalytic activity, such as splicing RNA.

Question 14

A patient is diagnosed with a genetic disorder caused by a single nucleotide substitution that results in a nonfunctional enzyme. Which type of mutation is most likely responsible?

Accepted Answer

Nonsense mutation

Question 15

Which of the following best explains why most carcinogens are also mutagens?

Accepted Answer

Mutagens cause changes in DNA that can lead to uncontrolled cell growth, a hallmark of cancer.

Question 16

Which of the following steps 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 17

Which of the following is a direct result of a frameshift mutation caused by the insertion of a single nucleotide within the coding region of a gene?

Accepted Answer

All codons downstream of the insertion are altered, potentially changing every amino acid after the mutation.

Question 18

Which of the following best describes the function of aminoacyl-tRNA synthetase?

Accepted Answer

It attaches the correct amino acid to its corresponding tRNA.

Question 19

A scientist uses CRISPR-Cas9 to introduce a double-strand break in a gene associated with a hereditary disease. What is the most likely outcome if a template with a normal gene sequence is provided?

Accepted Answer

The cell's repair machinery will use the template to correct the mutation, potentially curing the disease.

Gene Expression: From Gene to Protein (Chapter 17 Study Notes)

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