Q: Which of the following best describes the central dogma of molecular biology?

$$\text{DNA} \rightarrow \text{RNA} \rightarrow \text{Protein}$$

Question 1

Which of the following best explains why red-green color blindness is more common in males than in females?

Accepted Answer

Males have only one X chromosome, so a single recessive allele will result in the trait.

Question 2

A woman who is heterozygous for an X-linked recessive disorder and a man who does not have the disorder have a child. What is the probability that their son will have the disorder?

Accepted Answer

$$0.50$$

Question 3

Which chromosomal mutation is most likely to result in a gene being present in two copies on the same chromosome?

Accepted Answer

Duplication

Question 4

During DNA replication, which enzyme is responsible for joining Okazaki fragments on the lagging strand?

Accepted Answer

Ligase

Question 5

A scientist observes that after several rounds of DNA replication, the ends of chromosomes in somatic cells become shorter. Which enzyme is most directly related to preventing this shortening in germ cells?

Accepted Answer

Telomerase

Question 6

Which of the following best describes the central dogma of molecular biology?

Accepted Answer

$$	ext{DNA} ightarrow 	ext{RNA} ightarrow 	ext{Protein}$$

Question 7

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 8

Which of the following modifications occurs to eukaryotic pre-mRNA before it leaves the nucleus?

Accepted Answer

Addition of a 5’ cap and a poly-A tail

Question 9

A population of beetles has two alleles for shell color: green ($$G) $$and brown ($$g). If$$ $$p = 0.7$$ and $$q = 0.3$$, what is the expected frequency of heterozygotes under Hardy-Weinberg equilibrium?

Accepted Answer

$$2pq = 0.42$$

Question 10

Which of the following scenarios best illustrates the founder effect?

Accepted Answer

A few individuals colonize a new island, and their allele frequencies differ from the original population.

Question 11

Which type of natural selection increases the frequency of individuals with extreme phenotypes at both ends of the spectrum?

Accepted Answer

Disruptive selection

Question 12

A female mammal has two X chromosomes, but only one is active in each cell. What is the name of the inactivated X chromosome, and what is its function?

Accepted Answer

Barr body; ensures dosage compensation

Question 13

Which experiment provided evidence for the semi-conservative model of DNA replication?

Accepted Answer

Meselson-Stahl experiment

Question 14

Which of the following is NOT a condition required for Hardy-Weinberg equilibrium?

Accepted Answer

Small population size

Question 15

A segment of DNA is reversed end to end within the same chromosome. What type of chromosomal mutation is this?

Accepted Answer

Inversion

Question 16

Which of the following best explains why evolution does not produce perfect organisms?

Accepted Answer

Evolution is limited by historical constraints and existing variation.

Question 17

Which of the following is a difference between DNA and RNA?

Accepted Answer

DNA contains deoxyribose; RNA contains ribose.

Question 18

A frameshift mutation is most likely to result from which of the following?

Accepted Answer

An insertion or deletion not in multiples of three nucleotides

Question 19

Which of the following best describes the role of the SRY gene in human development?

Accepted Answer

It initiates the development of testes and male characteristics.

Question 20

Which of the following is an example of homology as evidence for evolution?

Accepted Answer

The similar bone structure in the forelimbs of whales, bats, and humans

Chromosomal Inheritance, DNA Replication, Gene Expression, and Evolution: Study Guide

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