Biology Test Biology Genetics & Evolution 2

Question 1

Which type of RNA carries amino acids to the ribosome during translation?

Accepted Answer

tRNA

Answer

Transfer RNA (tRNA) carries specific amino acids to the ribosome, matching anticodons to mRNA codons.

Question 2

A cell has the genotype AaBb. If the two genes assort independently, what fraction of offspring from self-fertilization will be AABB?

Accepted Answer

1/16

Answer

Each locus independently gives a 1/4 chance of AA, so the combined probability for AABB is 1/4 × 1/4 = 1/16.

Question 3

What is a frameshift mutation?

Accepted Answer

An insertion or deletion that alters the reading frame

Answer

Frameshift mutations result from insertions or deletions of nucleotides that are not multiples of three, disrupting the reading frame.

Question 4

Natural selection acting on quantitative traits toward an intermediate phenotype is called:

Accepted Answer

Stabilizing selection

Answer

Stabilizing selection favors intermediate phenotypes and reduces variation in a population over time.

Question 5

Which enzyme unwinds the DNA double helix during replication?

Accepted Answer

Helicase

Answer

Helicase breaks hydrogen bonds between complementary base pairs to unwind the double helix at the replication fork.

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