Question 1

Which experiment provided definitive evidence that DNA, and not protein, is the genetic material in cells?

Accepted Answer

Hershey-Chase experiment

Question 2

During DNA replication, which enzyme is responsible for synthesizing the new DNA strand by adding nucleotides to the 3' end?

Accepted Answer

DNA polymerase

Question 3

A cell is observed to have three copies of chromosome 21. What is this condition called, and which human aneuploidy does it represent?

Accepted Answer

Trisomy; Down syndrome

Question 4

Which of the following best describes the Meselson-Stahl experiment's contribution to our understanding of DNA replication?

Accepted Answer

It proved that DNA replication is semiconservative.

Question 5

A scientist is using PCR to amplify a segment of DNA. Which of the following is NOT required for a successful PCR reaction?

Accepted Answer

DNA ligase

Question 6

Which process involves the removal of introns from pre-mRNA in eukaryotes?

Accepted Answer

Splicing

Question 7

A patient is diagnosed with sickle cell anemia, which is caused by a single nucleotide change in the beta-globin gene. What type of mutation is this?

Accepted Answer

Missense mutation

Question 8

Which of the following best explains the law of independent assortment?

Accepted Answer

Alleles for a gene segregate independently of alleles for other genes during gamete formation.

Question 9

In eukaryotic cells, what is the function of the poly-A tail added to mRNA during processing?

Accepted Answer

It increases mRNA stability and prevents degradation.

Question 10

Which of the following is a real-world application of DNA sequencing technology?

Accepted Answer

Diagnosing genetic diseases by identifying mutations

Question 11

A researcher observes that a certain gene is expressed only when both alleles are present in the heterozygous state, but not in the homozygous state. What is this phenomenon called?

Accepted Answer

Incomplete dominance

Question 12

Which of the following best describes a nucleosome?

Accepted Answer

A segment of DNA wrapped around a core of histone proteins

Question 13

During meiosis, crossing over occurs at which structure?

Accepted Answer

Chiasma

Question 14

Which of the following is a survivable human aneuploidy?

Accepted Answer

Monosomy X (Turner syndrome)

Question 15

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 16

Which of the following statements about telomeres is correct?

Accepted Answer

Telomeres are repetitive DNA sequences at the ends of chromosomes that protect them from degradation.

Question 17

Which process is responsible for the formation of mature mRNA in eukaryotes, involving the removal of introns and joining of exons?

Accepted Answer

Alternative splicing

Question 18

A geneticist is studying a pedigree and notices that a trait appears in every generation and affects both males and females equally. What is the most likely mode of inheritance?

Accepted Answer

Autosomal dominant

Question 19

Which of the following best describes the function of a promoter in transcription?

Accepted Answer

It is the region where RNA polymerase binds to initiate transcription.

Question 20

A cell biologist is investigating the effect of a mutation that prevents the addition of a 5' cap to mRNA. What is the most likely consequence?

Accepted Answer

The mRNA will be rapidly degraded and not translated.

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