Question 1

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

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Question 2

A mutation that results in the addition or deletion of a base pair in DNA is called:

Accepted Answer

A frameshift mutation

Question 3

Which enzyme is responsible for unwinding the double-stranded DNA during replication?

Accepted Answer

Helicase

Question 4

In the lac operon, what happens when lactose is present in the environment?

Accepted Answer

Allolactose binds to the repressor, inactivating it and allowing transcription.

Question 5

Which of the following statements about DNA replication in bacteria is correct?

Accepted Answer

Replication is bidirectional and each daughter cell receives one copy of the DNA molecule.

Question 6

What is the function of DNA ligase during DNA replication?

Accepted Answer

It joins Okazaki fragments on the lagging strand.

Question 7

Which of the following best describes the difference between genotype and phenotype?

Accepted Answer

Genotype is the genetic makeup; phenotype is the expression of those genes.

Question 8

During transcription in prokaryotes, which sequence signals the end of transcription?

Accepted Answer

Terminator

Question 9

Which of the following is true about the genetic code?

Accepted Answer

It is degenerate, meaning most amino acids are encoded by more than one codon.

Question 10

Which of the following statements about operons is correct?

Accepted Answer

An operon consists of a promoter, operator, and structural genes they control.

Question 11

A scientist discovers a bacterial strain that cannot metabolize lactose even when it is present. Which mutation could explain this phenotype?

Accepted Answer

A mutation in the lacZ gene preventing β-galactosidase production.

Question 12

Which enzyme is responsible for synthesizing RNA from a DNA template during transcription?

Accepted Answer

RNA polymerase

Question 13

In eukaryotes, what is the role of snRNPs during mRNA processing?

Accepted Answer

They remove introns and splice exons together.

Question 14

Which of the following best explains why translation can begin before transcription is complete in bacteria?

Accepted Answer

Both processes occur in the cytoplasm, allowing ribosomes to access mRNA as it is being synthesized.

Question 15

Which of the following is a function of topoisomerase during DNA replication?

Accepted Answer

It relaxes supercoiling ahead of the replication fork.

Question 16

A base substitution mutation in a gene results in a codon change from UAU to UAA. What is the likely effect on the protein product?

Accepted Answer

Translation will terminate prematurely, resulting in a truncated protein.

Question 17

Which of the following statements about repressible operons is correct?

Accepted Answer

They are usually on but can be turned off by a corepressor.

Question 18

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

Accepted Answer

It transports amino acids to the ribosome and matches them to the mRNA codon.

Question 19

Which of the following provides the energy for DNA replication?

Accepted Answer

Hydrolysis of phosphate bonds in nucleoside triphosphates

Question 20

A patient is diagnosed with a genetic disease caused by a mutation in a gene encoding an enzyme. Which of the following best explains how this mutation could lead to disease?

Accepted Answer

The mutation alters the DNA sequence, leading to an altered mRNA, which produces a dysfunctional protein and results in altered cellular function.

Chapter 8

Guida di studio - Domande di pratica

Study guide - Flashcard