PCAT Biological 2

Question 1

Which enzyme is responsible for unwinding the DNA double helix during replication?

Accepted Answer

Helicase

Answer

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

Question 2

Which phase of meiosis results in the separation of homologous chromosomes?

Accepted Answer

Meiosis I Anaphase

Answer

During Anaphase I of meiosis, homologous chromosome pairs are pulled to opposite poles, reducing the chromosome number by half.

Question 3

What is the primary function of the smooth endoplasmic reticulum?

Accepted Answer

Lipid synthesis and detoxification

Answer

The smooth ER lacks ribosomes and is specialized for lipid synthesis, steroid hormone production, and detoxification of drugs.

Question 4

In a dihybrid cross between two AaBb parents, what fraction of offspring will be aabb?

Accepted Answer

1/16

Answer

Each trait independently assorts; the probability of aa is 1/4 and bb is 1/4, so aabb = 1/4 × 1/4 = 1/16.

Question 5

Which blood vessel carries oxygenated blood from the lungs to the heart?

Accepted Answer

Pulmonary vein

Answer

The pulmonary veins carry oxygenated blood from the lungs back to the left atrium of the heart.

PCAT - Pharmacy College Admission Test Practice Test