Question 1

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

Accepted Answer

Hershey-Chase experiment

Question 2

During DNA replication, what distinguishes the synthesis of the lagging strand from the leading strand?

Accepted Answer

Lagging strand is synthesized in Okazaki fragments, while leading strand is synthesized continuously

Question 3

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

Accepted Answer

Helicase

Question 4

In prokaryotic transcription, which consensus sequence is located approximately 10 nucleotides upstream of the transcription start site?

Accepted Answer

Pribnow box

Question 5

Which of the following best describes the function of the sigma factor in prokaryotic RNA polymerase?

Accepted Answer

It recognizes and binds to promoter sequences

Question 6

Which post-transcriptional modification is unique to eukaryotic mRNA and is essential for translation initiation?

Accepted Answer

5' capping

Question 7

A mutation changes a codon from $$	ext{UAA} to$$ $$	ext{UAC}. $$What type of mutation is this, and what is its likely effect?

Accepted Answer

Point mutation; converts a stop codon to a sense codon

Question 8

Which repair mechanism is primarily responsible for correcting UV-induced pyrimidine dimers in E. coli?

Accepted Answer

Photoreactive repair by DNA photolyase

Question 9

If a DNA sequence undergoes a single base insertion, what is the most likely consequence for the encoded protein?

Accepted Answer

A frameshift mutation

Question 10

Which of the following best explains the redundancy of the genetic code?

Accepted Answer

The third base in a codon can often vary without changing the amino acid (wobble)

Question 11

In translation, which site of the ribosome is responsible for accepting incoming aminoacyl-tRNA?

Accepted Answer

A site

Question 12

Which of the following is NOT a function of tRNA?

Accepted Answer

Catalyzing peptide bond formation

Question 13

Which repair system in E. coli uses MutS, MutL, and MutH proteins to correct replication errors?

Accepted Answer

Mismatch repair

Question 14

A patient is diagnosed with a Robertsonian translocation. Which of the following best describes this chromosomal abnormality?

Accepted Answer

A fusion of two acrocentric chromosomes at their centromeres

Question 15

Which of the following statements about polyploidy is correct?

Accepted Answer

Polyploidy can result in organisms with three or more haploid sets of chromosomes

Question 16

Which of the following best describes the function of enhancers in eukaryotic transcription?

Accepted Answer

They increase transcription by binding to activator proteins

Question 17

Which of the following is a consequence of non-disjunction during meiosis?

Accepted Answer

Aneuploidy

Question 18

Which of the following is a key difference between prokaryotic and eukaryotic transcription termination?

Accepted Answer

Prokaryotes use both rho-dependent and rho-independent mechanisms, while eukaryotes rely on polyadenylation signals

Question 19

A DNA double-strand break is repaired by non-homologous end joining (NHEJ). Which proteins are involved in recognizing and processing the break?

Accepted Answer

Ku70, Ku80, PKcs

Question 20

Which of the following best describes a transposon?

Accepted Answer

A DNA sequence that can move within the genome, causing mutations

Genetics Study Guide: DNA, Transcription, Translation, Mutations, and Chromosomal Aberrations

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