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 scientist wants to produce a large quantity of a specific DNA fragment for analysis. Which technique should they use, and what is the correct sequence of steps in this process?

Accepted Answer

Polymerase Chain Reaction (PCR); Denaturation, Annealing, Extension

Question 3

Which of the following statements about the lac operon in E. coli is correct?

Accepted Answer

It is an inducible operon that is usually off unless an inducer is present.

Question 4

A DNA sequence reads 5'-TACGGA-3'. What is the corresponding mRNA sequence produced during transcription?

Accepted Answer

5'-AUGCCU-3'

Question 5

Which enzyme is primarily responsible for synthesizing RNA during transcription?

Accepted Answer

RNA polymerase

Question 6

A mutation changes a codon from $$	ext{UAC} ($$tyrosine) to $$	ext{UAA} ($$stop codon). What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 7

Which of the following best explains why viruses are considered non-living?

Accepted Answer

They cannot carry out metabolism or reproduce independently outside a host cell.

Question 8

In the trp operon, what happens when tryptophan is present in high concentrations?

Accepted Answer

Tryptophan binds to the repressor, activating it and turning the operon off.

Question 9

Which of the following is a function of microRNA (miRNA) in eukaryotic cells?

Accepted Answer

Regulating gene expression by binding to complementary mRNA and inhibiting translation.

Question 10

A scientist inserts a gene for insulin into a bacterial plasmid, then introduces the plasmid into E. coli. Which enzyme is used to join the insulin gene to the plasmid, and what is this process called?

Accepted Answer

DNA ligase; recombinant DNA technology

Question 11

Which of the following best describes the difference between an inducible and a repressible operon?

Accepted Answer

An inducible operon is usually off and can be turned on by an inducer, while a repressible operon is usually on and can be turned off by a corepressor.

Question 12

Which of the following is a correct sequence of events in the lytic cycle of a bacteriophage?

Accepted Answer

Attachment, entry, synthesis, assembly, release

Question 13

Why is HIV classified as a retrovirus?

Accepted Answer

It uses reverse transcriptase to synthesize DNA from its RNA genome.

Question 14

Which of the following best describes the role of tumor suppressor genes?

Accepted Answer

They encode proteins that inhibit cell division and prevent uncontrolled cell growth.

Question 15

A scientist is making complementary DNA (cDNA) from mRNA. Which enzyme is required for this process, and what is the main purpose of cDNA in molecular biology?

Accepted Answer

Reverse transcriptase; cDNA is used to clone eukaryotic genes in prokaryotes.

Question 16

Which of the following best explains the role of noncoding RNAs such as miRNA and siRNA in gene regulation?

Accepted Answer

They bind to mRNA molecules and can degrade them or block their translation.

Question 17

A patient is diagnosed with a genetic disease caused by a point mutation that does not change the amino acid sequence of the protein. What type of mutation is this?

Accepted Answer

Silent mutation

Question 18

Which of the following is a real-world application of transgenic organisms?

Accepted Answer

Production of human insulin in genetically modified bacteria for diabetes treatment.

Question 19

During translation, what is the relationship between a codon and an anticodon?

Accepted Answer

A codon is a three-nucleotide sequence on mRNA that pairs with a complementary anticodon on tRNA.

Question 20

Which of the following best describes the function of a promoter in gene expression?

Accepted Answer

It is a DNA sequence where RNA polymerase binds to initiate transcription.

Final Exam Study Guide: Molecular Genetics, Gene Expression, and Biotechnology

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