HESI A2 Biology – 100 Multiple Choice Questions
(Latest Update) GRADED A+
1. Which organelle is responsible for generating most of the cell's ATP?
A. Nucleus
B. Ribosome
C. Mitochondrion
D. Golgi apparatus
Correct Answer: C – Mitochondria produce ATP via cellular respiration.
2. A cell that lacks a nucleus and membrane-bound organelles is classified
as:
A. Eukaryotic
B. Prokaryotic
C. Plant cell
D. Animal cell
Correct Answer: B – Prokaryotes (bacteria, archaea) have no nucleus or
membrane-bound organelles.
3. Which process involves the movement of water across a semipermeable
membrane from low solute concentration to high solute concentration?
A. Diffusion
B. Osmosis
C. Active transport
D. Phagocytosis
Correct Answer: B – Osmosis is the diffusion of water.
4. In DNA, which nitrogenous base pairs with guanine?
A. Adenine
B. Thymine
C. Cytosine
D. Uracil
Correct Answer: C – Guanine pairs with cytosine via three hydrogen bonds.
5. Which of the following is a haploid cell?
A. Skin cell
B. Liver cell
,C. Sperm cell
D. Nerve cell
Correct Answer: C – Sperm cells (gametes) contain half the chromosome
number.
6. The primary function of ribosomes is to:
A. Synthesize lipids
B. Package proteins
C. Synthesize proteins
D. Store genetic material
Correct Answer: C – Ribosomes translate mRNA into polypeptide chains.
7. Which phase of the cell cycle does DNA replication occur?
A. G1 phase
B. S phase
C. G2 phase
D. M phase
Correct Answer: B – Synthesis (S) phase duplicates chromosomes.
8. A plant is exposed to a light spectrum that lacks red and blue
wavelengths. What will happen?
A. Increased photosynthesis
B. No effect
C. Reduced photosynthesis
D. Enhanced chlorophyll production
Correct Answer: C – Red and blue light are most effective for photosynthesis.
9. Which type of RNA carries amino acids to the ribosome during
translation?
A. mRNA
B. rRNA
C. tRNA
D. snRNA
Correct Answer: C – Transfer RNA (tRNA) has an anticodon and carries specific
amino acids.
10. What is the end product of glycolysis?
A. Glucose
B. Pyruvate
C. Acetyl-CoA
D. Lactic acid
Correct Answer: B – Glycolysis splits one glucose into two pyruvate molecules.
11. Which of the following is an example of a homozygous dominant
genotype?
A. Aa
B. aa
C. AA
, D. Ab
Correct Answer: C – AA has two identical dominant alleles.
12. In a food web, which organisms occupy the first trophic level?
A. Primary consumers
B. Secondary consumers
C. Producers
D. Decomposers
Correct Answer: C – Producers (plants, algae) convert sunlight into chemical
energy.
13. Which cellular structure is responsible for detoxifying harmful
substances, especially in liver cells?
A. Rough ER
B. Smooth ER
C. Lysosome
D. Peroxisome
Correct Answer: B – Smooth ER contains detoxification enzymes.
14. A scientist wants to test a new antibiotic on bacteria. He gives the
antibiotic to one group and saline to another. The saline group is the:
A. Control group
B. Experimental group
C. Dependent variable
D. Constant
Correct Answer: A – The control group receives no treatment for comparison.
15. Which of the following is NOT a characteristic of all living things?
A. Reproduction
B. Response to stimuli
C. Ability to move
D. Growth and development
Correct Answer: C – Many living things (e.g., plants, fungi) are sessile.
16. During which stage of mitosis do chromosomes align at the metaphase
plate?
A. Prophase
B. Metaphase
C. Anaphase
D. Telophase
Correct Answer: B – Chromosomes line up at the equatorial plane.
17. What is the complementary mRNA sequence to the DNA template
strand 3'-TACGGT-5'?
A. 5'-AUGCCA-3'
B. 5'-UACGGU-3'
C. 5'-ATGCCA-3'
D. 5'-AUGCCU-3'
(Latest Update) GRADED A+
1. Which organelle is responsible for generating most of the cell's ATP?
A. Nucleus
B. Ribosome
C. Mitochondrion
D. Golgi apparatus
Correct Answer: C – Mitochondria produce ATP via cellular respiration.
2. A cell that lacks a nucleus and membrane-bound organelles is classified
as:
A. Eukaryotic
B. Prokaryotic
C. Plant cell
D. Animal cell
Correct Answer: B – Prokaryotes (bacteria, archaea) have no nucleus or
membrane-bound organelles.
3. Which process involves the movement of water across a semipermeable
membrane from low solute concentration to high solute concentration?
A. Diffusion
B. Osmosis
C. Active transport
D. Phagocytosis
Correct Answer: B – Osmosis is the diffusion of water.
4. In DNA, which nitrogenous base pairs with guanine?
A. Adenine
B. Thymine
C. Cytosine
D. Uracil
Correct Answer: C – Guanine pairs with cytosine via three hydrogen bonds.
5. Which of the following is a haploid cell?
A. Skin cell
B. Liver cell
,C. Sperm cell
D. Nerve cell
Correct Answer: C – Sperm cells (gametes) contain half the chromosome
number.
6. The primary function of ribosomes is to:
A. Synthesize lipids
B. Package proteins
C. Synthesize proteins
D. Store genetic material
Correct Answer: C – Ribosomes translate mRNA into polypeptide chains.
7. Which phase of the cell cycle does DNA replication occur?
A. G1 phase
B. S phase
C. G2 phase
D. M phase
Correct Answer: B – Synthesis (S) phase duplicates chromosomes.
8. A plant is exposed to a light spectrum that lacks red and blue
wavelengths. What will happen?
A. Increased photosynthesis
B. No effect
C. Reduced photosynthesis
D. Enhanced chlorophyll production
Correct Answer: C – Red and blue light are most effective for photosynthesis.
9. Which type of RNA carries amino acids to the ribosome during
translation?
A. mRNA
B. rRNA
C. tRNA
D. snRNA
Correct Answer: C – Transfer RNA (tRNA) has an anticodon and carries specific
amino acids.
10. What is the end product of glycolysis?
A. Glucose
B. Pyruvate
C. Acetyl-CoA
D. Lactic acid
Correct Answer: B – Glycolysis splits one glucose into two pyruvate molecules.
11. Which of the following is an example of a homozygous dominant
genotype?
A. Aa
B. aa
C. AA
, D. Ab
Correct Answer: C – AA has two identical dominant alleles.
12. In a food web, which organisms occupy the first trophic level?
A. Primary consumers
B. Secondary consumers
C. Producers
D. Decomposers
Correct Answer: C – Producers (plants, algae) convert sunlight into chemical
energy.
13. Which cellular structure is responsible for detoxifying harmful
substances, especially in liver cells?
A. Rough ER
B. Smooth ER
C. Lysosome
D. Peroxisome
Correct Answer: B – Smooth ER contains detoxification enzymes.
14. A scientist wants to test a new antibiotic on bacteria. He gives the
antibiotic to one group and saline to another. The saline group is the:
A. Control group
B. Experimental group
C. Dependent variable
D. Constant
Correct Answer: A – The control group receives no treatment for comparison.
15. Which of the following is NOT a characteristic of all living things?
A. Reproduction
B. Response to stimuli
C. Ability to move
D. Growth and development
Correct Answer: C – Many living things (e.g., plants, fungi) are sessile.
16. During which stage of mitosis do chromosomes align at the metaphase
plate?
A. Prophase
B. Metaphase
C. Anaphase
D. Telophase
Correct Answer: B – Chromosomes line up at the equatorial plane.
17. What is the complementary mRNA sequence to the DNA template
strand 3'-TACGGT-5'?
A. 5'-AUGCCA-3'
B. 5'-UACGGU-3'
C. 5'-ATGCCA-3'
D. 5'-AUGCCU-3'
