MCQ Collection
MDCAT 2026 MCQs
Practice MDCAT 2026 questions with answers and explanations.
Choose an option to check your answer.
Correct Answer: C. A process releasing heat to the surroundings
Explanation:
Exothermic processes have negative enthalpy change under the usual convention.
The surroundings gain heat.
Choose an option to check your answer.
Correct Answer: D. A process absorbing heat from the surroundings
Explanation:
Endothermic processes have positive enthalpy change.
The system gains heat.
Choose an option to check your answer.
Correct Answer: D. The two alleles of a gene separate during gamete formation
Explanation:
Each gamete receives one allele from a pair.
Fertilization restores the pair.
Choose an option to check your answer.
Correct Answer: D. 200 kPa
Explanation:
Use P1/T1=P2/T2.
P2=100×600/300 = 200 kPa.
Choose an option to check your answer.
Correct Answer: A. Alleles of different genes assort independently when genes are unlinked
Explanation:
Independent assortment arises from random orientation of homologous pairs.
Linked genes may not assort independently.
Choose an option to check your answer.
Correct Answer: A. 0.987 mol
Explanation:
Use n=PV/RT.
N=100×24.6/(8.31×300)≈0.987 mol.
Choose an option to check your answer.
Correct Answer: B. Alleles of different genes assort independently when genes are unlinked
Explanation:
Independent assortment arises from random orientation of homologous pairs.
Linked genes may not assort independently.
Choose an option to check your answer.
Correct Answer: B. 100 kPa
Explanation:
Dalton's law adds partial pressures.
20+35+45 = 100 kPa.
Choose an option to check your answer.
Correct Answer: C. Alleles of different genes assort independently when genes are unlinked
Explanation:
Independent assortment arises from random orientation of homologous pairs.
Linked genes may not assort independently.
Choose an option to check your answer.
Correct Answer: C. 1.0 mol
Explanation:
Moles equal molarity times volume in liters.
0.50×2.0 = 1.0 mol.
Choose an option to check your answer.
Correct Answer: D. A heritable change in genetic material
Explanation:
Mutations may alter one base, a gene, or chromosome structure.
They create genetic variation.
Choose an option to check your answer.
Correct Answer: A. An allele whose effect is masked in a heterozygote
Explanation:
A recessive phenotype usually appears when no dominant allele is present.
The allele can still be transmitted by carriers.
