Question 1

Which of the following best describes an Open Reading Frame (ORF) in genetics?

Accepted Answer

A continuous stretch of codons in mRNA that begins with a start codon and ends at a stop codon, potentially encoding a protein.

Question 2

How many possible reading frames exist in a single-stranded mRNA molecule?

Accepted Answer

Three

Question 3

What is the most likely consequence of translating an mRNA in the wrong reading frame?

Accepted Answer

A nonfunctional or truncated protein due to premature stop codons.

Question 4

Which of the following statements about exons and introns is correct?

Accepted Answer

Exons are coding regions that remain in mature mRNA, while introns are non-coding regions removed during splicing.

Question 5

During eukaryotic transcription, which event occurs first?

Accepted Answer

Transcription of DNA into pre-mRNA

Question 6

Which of the following best defines the exome?

Accepted Answer

All the exons (coding regions) of a genome.

Question 7

A linkage map is constructed based on which of the following?

Accepted Answer

Frequency of recombination between genetic markers.

Question 8

Which equation correctly represents the relationship between recombination frequencies for three genes A, B, and C, where B is between A and C?

Accepted Answer

$$RF(A-B) + RF(B-C) \u003e RF(A-C)$$

Question 9

Which of the following is a key difference between a restriction map and a linkage map?

Accepted Answer

A restriction map shows the physical distances between DNA markers, while a linkage map shows genetic distances based on recombination.

Question 10

Which of the following best describes a genetic polymorphism?

Accepted Answer

The presence of two or more alleles at a locus with an allele frequency greater than 1% in the population.

Question 11

Which of the following is true about most genetic polymorphisms in the human genome?

Accepted Answer

They are mostly found in non-coding, repetitive DNA regions.

Question 12

Short Tandem Repeats (STRs) are useful in forensic analysis because:

Accepted Answer

They exhibit high variation, making it unlikely for two unrelated individuals to have the same STR profile.

Question 13

Which of the following statements about transposons is correct?

Accepted Answer

Transposons are repetitive DNA elements that can move to new locations in the genome and often make their own reverse transcriptase.

Question 14

Which of the following is a practical application of single nucleotide polymorphisms (SNPs)?

Accepted Answer

Mapping disease-associated mutations through genome-wide association studies (GWAS).

Question 15

Which of the following best explains why larger genomes do not necessarily contain more genes?

Accepted Answer

Larger genomes contain more repetitive DNA, much of which is derived from transposable elements.

Question 16

Which of the following is true about mitochondrial DNA (mtDNA)?

Accepted Answer

It is circular, resembles bacterial genomes, and varies in size and gene content among species.

Question 17

Which of the following best describes the process of gene identification using sequencing maps?

Accepted Answer

It uses knowledge of gene structure and sequence features, followed by experimental verification.

Question 18

Which of the following is a reason why most polymorphisms in higher organisms are found in non-coding regions?

Accepted Answer

Non-coding regions are less likely to affect organismal fitness, allowing more variation to persist.

Question 19

Which of the following best describes the difference between a deleterious mutation and a neutral polymorphism?

Accepted Answer

Deleterious mutations directly cause disease and are under strong selection, while neutral polymorphisms do not significantly affect viability or fertility.

Question 20

Which of the following is a correct statement about organelle DNA inheritance?

Accepted Answer

Organelle DNA, such as mitochondrial DNA, is usually inherited from the egg and evolves at a different rate than nuclear DNA.

Genome Content, Gene Mapping, and Genetic Polymorphism: Study Notes for Genetics

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