Question 1

Which of the following best describes the structure of a nucleosome in eukaryotic chromatin?

Accepted Answer

A segment of DNA wrapped around a core of eight histone proteins

Question 2

A researcher is analyzing a DNA sample and finds a region with the sequence 'GATA' repeated 12 times in a row. This region is most likely an example of which genetic marker?

Accepted Answer

Short tandem repeat (STR)

Question 3

Which of the following best explains why single-nucleotide polymorphisms (SNPs) are useful as genetic markers even if they do not cause phenotypic changes?

Accepted Answer

SNPs are inherited in a Mendelian fashion and can be used to track inheritance patterns

Question 4

A diploid organism has a ploidy level of 2. What does this mean in terms of chromosome number?

Accepted Answer

It has two homologues of each chromosome

Question 5

During meiosis, if homologous chromosomes fail to separate during anaphase I, what is the most likely outcome?

Accepted Answer

Some gametes will have an abnormal number of chromosomes (aneuploidy)

Question 6

Which chromosomal feature is the attachment site for spindle fibers during cell division?

Accepted Answer

Kinetochore

Question 7

Epigenetic changes can affect gene expression without altering the DNA sequence. Which of the following is an example of such a change?

Accepted Answer

Methylation of cytosine bases in DNA

Question 8

Which of the following is a post-translational modification that can regulate protein function?

Accepted Answer

Phosphorylation

Question 9

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

Accepted Answer

Nonsense mutation

Question 10

In the lac operon of E. coli, what would be the effect of a mutation that inactivates the repressor protein?

Accepted Answer

The operon would be expressed even in the absence of lactose

Question 11

Why do spontaneous mutations occur at a low rate in cells?

Accepted Answer

Cells have DNA repair mechanisms that correct most errors

Question 12

A chromosomal inversion occurs when:

Accepted Answer

A segment of a chromosome is reversed end to end

Question 13

Which environmental factor is most likely to increase the mutation rate in skin cells?

Accepted Answer

Exposure to ultraviolet (UV) radiation

Question 14

A patient is found to have a deletion of a segment on chromosome 5. Which of the following is a possible consequence?

Accepted Answer

Loss of one or more genes, potentially leading to disease

Question 15

Which of the following best describes sister chromatids?

Accepted Answer

Identical copies of a chromosome joined at the centromere

Question 16

A short tandem repeat (STR) is useful in forensic DNA analysis because:

Accepted Answer

The number of repeats varies greatly among individuals

Question 17

Which of the following equations correctly represents the probability of two independent events both occurring?

Accepted Answer

$$P(A \ 	ext{and} \ B) = P(A) 	imes P(B)$$

Question 18

A translocation mutation can result in which of the following outcomes?

Accepted Answer

Exchange of genetic material between non-homologous chromosomes

Question 19

Which of the following best describes a centromere?

Accepted Answer

The region of a chromosome where sister chromatids are joined

Question 20

Which of the following is a likely effect of a frameshift mutation in a protein-coding gene?

Accepted Answer

Alteration of the reading frame, resulting in a nonfunctional protein

Genetics Study Guide: DNA Structure, Chromosome Organization, Genome Transmission, and Mutations

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