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

Question 1

Which statement best explains the relationship between genotype and phenotype as described in gene expression?

Accepted Answer

Proteins act as the link between genotype and phenotype by being synthesized according to genetic instructions.

Question 2

Archibald Garrod's study of metabolic defects led to which important hypothesis about genes?

Accepted Answer

Genes dictate phenotypes through enzymes that catalyze specific chemical reactions.

Question 3

In the classic Neurospora experiment, what was the main conclusion regarding the function of genes?

Accepted Answer

Each gene codes for a specific enzyme required in a metabolic pathway.

Question 4

Why was the 'one gene-one enzyme' hypothesis revised to 'one gene-one polypeptide'?

Accepted Answer

Because not all proteins are enzymes and many proteins consist of multiple polypeptides, each encoded by a different gene.

Question 5

Which process describes the synthesis of RNA using information in DNA?

Accepted Answer

Transcription

Question 6

In eukaryotic cells, what is the main reason that transcription and translation are separated?

Accepted Answer

The nuclear envelope separates transcription in the nucleus from translation in the cytoplasm.

Question 7

The central dogma of molecular biology can be summarized by which sequence?

Accepted Answer

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

Question 8

How many nucleotides are required to code for a single amino acid in the genetic code?

Accepted Answer

$$3$$

Question 9

What is the consequence of a frameshift mutation caused by a single nucleotide insertion within a coding region?

Accepted Answer

All codons downstream of the mutation are altered, potentially resulting in a nonfunctional protein.

Question 10

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

Accepted Answer

tRNA transfers amino acids to the growing polypeptide chain by matching its anticodon to the mRNA codon.

Question 11

What is the function of the promoter region in transcription?

Accepted Answer

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

Question 12

Which modification occurs at the 3' end of a eukaryotic pre-mRNA molecule during RNA processing?

Accepted Answer

Addition of a poly-A tail

Question 13

Alternative RNA splicing allows for which of the following outcomes?

Accepted Answer

A single gene can encode multiple types of polypeptides.

Question 14

Which enzyme is responsible for catalyzing the attachment of amino acids to tRNA molecules?

Accepted Answer

Aminoacyl-tRNA synthetase

Question 15

During translation, what is the role of the P site on the ribosome?

Accepted Answer

It holds the tRNA carrying the growing polypeptide chain.

Question 16

What is the effect of a nonsense mutation in a coding region of a gene?

Accepted Answer

It changes a codon to a stop codon, resulting in premature termination of translation.

Question 17

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

Accepted Answer

The genetic code is redundant but not ambiguous.

Question 18

A scientist uses CRISPR-Cas9 to 'knock out' a gene in mice. What is the most likely immediate molecular result?

Accepted Answer

The Cas9 protein cuts both strands of the targeted gene, triggering DNA repair mechanisms.

Question 19

Which of the following best describes a ribozyme?

Accepted Answer

A catalytic RNA molecule that can function as an enzyme.

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

Study Guide - Practice Questions