Question 1

Which statement best describes the central dogma of molecular biology?

Accepted Answer

Genetic information flows from DNA to RNA to protein.

Question 2

During DNA replication, which enzyme is responsible for synthesizing the new DNA strand by adding nucleotides to the growing chain?

Accepted Answer

DNA polymerase

Question 3

A mutation changes a codon from UAU (tyrosine) to UAA (stop codon). What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 4

Which process is most directly responsible for removing introns from pre-mRNA in eukaryotes?

Accepted Answer

Splicing

Question 5

In the Hershey-Chase experiment, what was the key evidence that DNA is the genetic material?

Accepted Answer

Radioactive phosphorus was found inside the bacteria.

Question 6

Which of the following best describes semiconservative DNA replication?

Accepted Answer

Each daughter DNA molecule contains one parental and one newly synthesized strand.

Question 7

A population of butterflies has two alleles for wing color: A and a. If the frequency of allele A is $$p = 0.7$$ and allele a is $$q = 0.3$$, what is the expected frequency of heterozygotes under Hardy-Weinberg equilibrium?

Accepted Answer

$$2pq = 0.42$$

Question 8

Which of the following is a function of histone modification in gene regulation?

Accepted Answer

It alters chromatin structure to regulate gene expression.

Question 9

Which repair mechanism is most likely to fix a deaminated cytosine in DNA?

Accepted Answer

Base excision repair

Question 10

A researcher exposes cells to ionizing radiation. Which type of DNA damage is most likely to occur?

Accepted Answer

Double-strand breaks

Question 11

Which of the following best explains the founder effect in population genetics?

Accepted Answer

A small group establishes a new population with reduced genetic diversity.

Question 12

Which operon is inducible and activated in the presence of lactose in E. coli?

Accepted Answer

lac operon

Question 13

A patient has a mutation in the BRCA1 gene, leading to impaired DNA repair. Which type of cancer is most commonly associated with this mutation?

Accepted Answer

Breast cancer

Question 14

Which of the following is a role of long noncoding RNAs (lncRNAs) in gene expression?

Accepted Answer

They modulate chromatin structure and transcriptional activity.

Question 15

Which process is responsible for the termination of bacterial transcription?

Accepted Answer

Formation of a hairpin loop in the RNA followed by dissociation of RNA polymerase

Question 16

A geneticist observes that a population is not in Hardy-Weinberg equilibrium. Which factor could be responsible?

Accepted Answer

Non-random mating

Question 17

Which of the following best describes the effect of DNA methylation on gene expression?

Accepted Answer

It generally represses transcription of the gene.

Question 18

A cell cycle checkpoint fails, allowing cells with damaged DNA to proceed. What is a likely consequence?

Accepted Answer

Genomic instability and potential tumor formation

Question 19

Which of the following is a difference between base excision repair and nucleotide excision repair?

Accepted Answer

Base excision repair removes single damaged bases, while nucleotide excision repair removes bulky DNA adducts.

Question 20

A population of 1000 individuals has 360 homozygous dominant (AA), 480 heterozygous (Aa), and 160 homozygous recessive (aa) individuals. What is the frequency of allele A?

Accepted Answer

$$f(A) = \frac{2 	imes 360 + 480}{2 	imes 1000} = 0.6$$

Comprehensive Study Guide: Genetics Final Exam Topics

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