HESI A2 Biology Exam 2025/2026 –
Verified Questions & 100% Correct
Answers | Pass on First Attempt
Question 1
Which organelle is responsible for protein synthesis? A. Nucleus B. Mitochondria C. Ribosome
D. Golgi apparatus
Correct Answer: C
Rationale: In cellular biology, ribosomes are the sites of protein synthesis, translating mRNA
into polypeptides. This process is essential for all cellular functions, including enzyme
production in human anatomy like muscle contraction.
Question 2
Why is yeast used to make bread rise? A. It performs photosynthesis B. It carries out
fermentation, producing ethanol and carbon dioxide C. It absorbs nutrients from flour D. It
secretes enzymes for digestion
Correct Answer: B
Rationale: Cellular biology involves anaerobic respiration (fermentation) in yeast, releasing
CO2 that causes dough to rise. This demonstrates metabolic pathways similar to those in human
muscle cells during exercise.
Question 3
How is mitosis different from meiosis? A. Mitosis produces gametes; meiosis produces somatic
cells B. Mitosis creates cells with half the chromosomes; meiosis creates identical cells C.
Meiosis creates sex cells with half the chromosomes; mitosis creates exact copies D. Both
produce four identical daughter cells
Correct Answer: C
Rationale: Cell division in biology: mitosis for growth/repair (diploid cells), meiosis for genetic
diversity in gametes (haploid). This ties to genetics, ensuring variation for evolution.
Question 4
What can be altered by mutations? A. Carbohydrates B. Lipids C. DNA D. Proteins
,Correct Answer: C
Rationale: Genetics: Mutations change DNA sequence, affecting gene expression and leading to
evolutionary adaptations or diseases like sickle cell anemia in human anatomy.
Question 5
What is single-stranded? A. DNA B. Chromosomes C. RNA D. Histones
Correct Answer: C
Rationale: Cellular biology: RNA is single-stranded for flexibility in transcription/translation,
contrasting double-stranded DNA for stability in genetic storage.
Question 6
What contains uracil? A. DNA B. tRNA C. mRNA D. RNA (all types)
Correct Answer: D
Rationale: Molecular biology: Uracil replaces thymine in RNA, crucial for protein synthesis.
This distinction supports accurate genetic coding in human cellular processes.
Question 7
What codes for proteins? A. RNA B. Proteins C. DNA D. Carbohydrates
Correct Answer: C
Rationale: Genetics: DNA's nucleotide sequence codes for amino acids via transcription to
mRNA, fundamental to cellular biology and phenotypic traits in evolution.
Question 8
Two parents carry the recessive gene for cystic fibrosis. What percentage of offspring are
carriers but not affected? A. 25% B. 50% C. 75% D. 100%
Correct Answer: B
Rationale: Genetics: Punnett square for Aa x Aa yields 50% heterozygous carriers. This
autosomal recessive inheritance affects human anatomy (lungs/pancreas).
Question 9
A cell in a solution with higher solute concentration inside than outside will: A. Shrink B. Swell
and burst C. Remain unchanged D. Divide
, Correct Answer: B
Rationale: Cellular biology: Hypotonic solution causes osmosis, water influx leading to lysis.
Relevant to human red blood cells in hypotonic IV fluids.
Question 10
What is the purpose of phloem in plant stems? A. Water transport B. Food conduction C.
Structural support D. Gas exchange
Correct Answer: B
Rationale: Cellular biology: Phloem transports sugars (products of photosynthesis), analogous
to circulatory system in human anatomy for nutrient distribution.
Question 11
Physical factors like temperature alter enzyme activity by affecting the enzyme's: A. Size B.
Color C. Shape D. Weight
Correct Answer: C
Rationale: Cellular biology: Enzymes are proteins; denaturation changes shape, disrupting
active site. Ties to metabolism in human physiology (e.g., fever effects).
Question 12
Which plant reproductive part is male? A. Pistil B. Ovary C. Stamen D. Sepal
Correct Answer: C
Rationale: Human anatomy parallel: Stamen (anther/filament) produces pollen like testes
produce sperm, supporting reproduction and genetic diversity.
Question 13
What symbiosis exists between pneumonia bacteria and humans? A. Mutualism B.
Commensalism C. Parasitism D. Neutralism
Correct Answer: C
Rationale: Evolution/ecology: Pathogenic bacteria harm host (pneumonia in lungs), benefiting
at host's expense, driving immune evolution in humans.
Question 14
Verified Questions & 100% Correct
Answers | Pass on First Attempt
Question 1
Which organelle is responsible for protein synthesis? A. Nucleus B. Mitochondria C. Ribosome
D. Golgi apparatus
Correct Answer: C
Rationale: In cellular biology, ribosomes are the sites of protein synthesis, translating mRNA
into polypeptides. This process is essential for all cellular functions, including enzyme
production in human anatomy like muscle contraction.
Question 2
Why is yeast used to make bread rise? A. It performs photosynthesis B. It carries out
fermentation, producing ethanol and carbon dioxide C. It absorbs nutrients from flour D. It
secretes enzymes for digestion
Correct Answer: B
Rationale: Cellular biology involves anaerobic respiration (fermentation) in yeast, releasing
CO2 that causes dough to rise. This demonstrates metabolic pathways similar to those in human
muscle cells during exercise.
Question 3
How is mitosis different from meiosis? A. Mitosis produces gametes; meiosis produces somatic
cells B. Mitosis creates cells with half the chromosomes; meiosis creates identical cells C.
Meiosis creates sex cells with half the chromosomes; mitosis creates exact copies D. Both
produce four identical daughter cells
Correct Answer: C
Rationale: Cell division in biology: mitosis for growth/repair (diploid cells), meiosis for genetic
diversity in gametes (haploid). This ties to genetics, ensuring variation for evolution.
Question 4
What can be altered by mutations? A. Carbohydrates B. Lipids C. DNA D. Proteins
,Correct Answer: C
Rationale: Genetics: Mutations change DNA sequence, affecting gene expression and leading to
evolutionary adaptations or diseases like sickle cell anemia in human anatomy.
Question 5
What is single-stranded? A. DNA B. Chromosomes C. RNA D. Histones
Correct Answer: C
Rationale: Cellular biology: RNA is single-stranded for flexibility in transcription/translation,
contrasting double-stranded DNA for stability in genetic storage.
Question 6
What contains uracil? A. DNA B. tRNA C. mRNA D. RNA (all types)
Correct Answer: D
Rationale: Molecular biology: Uracil replaces thymine in RNA, crucial for protein synthesis.
This distinction supports accurate genetic coding in human cellular processes.
Question 7
What codes for proteins? A. RNA B. Proteins C. DNA D. Carbohydrates
Correct Answer: C
Rationale: Genetics: DNA's nucleotide sequence codes for amino acids via transcription to
mRNA, fundamental to cellular biology and phenotypic traits in evolution.
Question 8
Two parents carry the recessive gene for cystic fibrosis. What percentage of offspring are
carriers but not affected? A. 25% B. 50% C. 75% D. 100%
Correct Answer: B
Rationale: Genetics: Punnett square for Aa x Aa yields 50% heterozygous carriers. This
autosomal recessive inheritance affects human anatomy (lungs/pancreas).
Question 9
A cell in a solution with higher solute concentration inside than outside will: A. Shrink B. Swell
and burst C. Remain unchanged D. Divide
, Correct Answer: B
Rationale: Cellular biology: Hypotonic solution causes osmosis, water influx leading to lysis.
Relevant to human red blood cells in hypotonic IV fluids.
Question 10
What is the purpose of phloem in plant stems? A. Water transport B. Food conduction C.
Structural support D. Gas exchange
Correct Answer: B
Rationale: Cellular biology: Phloem transports sugars (products of photosynthesis), analogous
to circulatory system in human anatomy for nutrient distribution.
Question 11
Physical factors like temperature alter enzyme activity by affecting the enzyme's: A. Size B.
Color C. Shape D. Weight
Correct Answer: C
Rationale: Cellular biology: Enzymes are proteins; denaturation changes shape, disrupting
active site. Ties to metabolism in human physiology (e.g., fever effects).
Question 12
Which plant reproductive part is male? A. Pistil B. Ovary C. Stamen D. Sepal
Correct Answer: C
Rationale: Human anatomy parallel: Stamen (anther/filament) produces pollen like testes
produce sperm, supporting reproduction and genetic diversity.
Question 13
What symbiosis exists between pneumonia bacteria and humans? A. Mutualism B.
Commensalism C. Parasitism D. Neutralism
Correct Answer: C
Rationale: Evolution/ecology: Pathogenic bacteria harm host (pneumonia in lungs), benefiting
at host's expense, driving immune evolution in humans.
Question 14
