HESI A2 Biology Foundations 2024/2025 – 100% Verified
Answers with Core Science Clarifications
Cell Biology
Question 1: Which organelle is responsible for protein synthesis in eukaryotic cells?
a) Nucleus
b) Ribosome
c) Mitochondrion
d) Golgi apparatus
Answer: b) Ribosome
Explanation: Ribosomes, either free in the cytoplasm or bound to the endoplasmic retic-
ulum, synthesize proteins by translating mRNA into polypeptide chains.
Question 2: What is the primary function of the cell membrane?
a) Energy production
b) Selective permeability
c) DNA storage
d) Protein modification
Answer: b) Selective permeability
Explanation: The cell membrane regulates the passage of substances in and out of the
cell, maintaining homeostasis through its selectively permeable lipid bilayer.
Question 3: Which process moves molecules against their concentration gradient?
a) Diffusion
b) Osmosis
c) Active transport
d) Facilitated diffusion
Answer: c) Active transport
Explanation: Active transport uses energy, typically ATP, to move molecules against
their concentration gradient, as seen in the sodium-potassium pump.
Question 4: What is the primary role of chloroplasts in plant cells?
a) Waste digestion
b) Photosynthesis
c) Protein synthesis
d) Cell division
Answer: b) Photosynthesis
Explanation: Chloroplasts contain chlorophyll, which captures sunlight to convert car-
bon dioxide and water into glucose and oxygen during photosynthesis.
Question 5: Which structure provides structural support in plant cells?
a) Cell membrane
b) Cell wall
c) Cytoplasm
d) Nucleus
Answer: b) Cell wall
Explanation: The cell wall, composed primarily of cellulose, provides rigidity and sup-
port to plant cells, maintaining their shape.
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, Question 6: What is the term for programmed cell death?
a) Mitosis
b) Apoptosis
c) Meiosis
d) Cytokinesis
Answer: b) Apoptosis
Explanation: Apoptosis is a controlled process of cell death that eliminates damaged or
unnecessary cells, crucial for development and tissue maintenance.
Question 7: Which organelle packages and distributes proteins?
a) Lysosome
b) Mitochondrion
c) Golgi apparatus
d) Endoplasmic reticulum
Answer: c) Golgi apparatus
Explanation: The Golgi apparatus modifies, sorts, and packages proteins and lipids into
vesicles for secretion or cellular use.
Question 8: What is the primary energy currency of the cell?
a) Glucose
b) ATP
c) DNA
d) RNA
Answer: b) ATP
Explanation: Aden TP (adenosine triphosphate) provides energy for cellular processes
by releasing energy when its phosphate bonds are broken.
Question 9: Which type of cell lacks membrane-bound organelles?
a) Eukaryotic
b) Prokaryotic
c) Plant
d) Animal
Answer: b) Prokaryotic
Explanation: Prokaryotic cells, such as bacteria, lack membrane-bound organelles like
a nucleus, with DNA in a nucleoid region.
Question 10: What process divides the cytoplasm during cell division?
a) Mitosis
b) Meiosis
c) Cytokinesis
d) Interphase
Answer: c) Cytokinesis
Explanation: Cytokinesis follows mitosis, dividing the cytoplasm and organelles be-
tween daughter cells to complete cell division.
Question 11: Which organelle contains enzymes for intracellular digestion?
a) Peroxisome
b) Lysosome
c) Ribosome
d) Nucleus
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Answers with Core Science Clarifications
Cell Biology
Question 1: Which organelle is responsible for protein synthesis in eukaryotic cells?
a) Nucleus
b) Ribosome
c) Mitochondrion
d) Golgi apparatus
Answer: b) Ribosome
Explanation: Ribosomes, either free in the cytoplasm or bound to the endoplasmic retic-
ulum, synthesize proteins by translating mRNA into polypeptide chains.
Question 2: What is the primary function of the cell membrane?
a) Energy production
b) Selective permeability
c) DNA storage
d) Protein modification
Answer: b) Selective permeability
Explanation: The cell membrane regulates the passage of substances in and out of the
cell, maintaining homeostasis through its selectively permeable lipid bilayer.
Question 3: Which process moves molecules against their concentration gradient?
a) Diffusion
b) Osmosis
c) Active transport
d) Facilitated diffusion
Answer: c) Active transport
Explanation: Active transport uses energy, typically ATP, to move molecules against
their concentration gradient, as seen in the sodium-potassium pump.
Question 4: What is the primary role of chloroplasts in plant cells?
a) Waste digestion
b) Photosynthesis
c) Protein synthesis
d) Cell division
Answer: b) Photosynthesis
Explanation: Chloroplasts contain chlorophyll, which captures sunlight to convert car-
bon dioxide and water into glucose and oxygen during photosynthesis.
Question 5: Which structure provides structural support in plant cells?
a) Cell membrane
b) Cell wall
c) Cytoplasm
d) Nucleus
Answer: b) Cell wall
Explanation: The cell wall, composed primarily of cellulose, provides rigidity and sup-
port to plant cells, maintaining their shape.
1
, Question 6: What is the term for programmed cell death?
a) Mitosis
b) Apoptosis
c) Meiosis
d) Cytokinesis
Answer: b) Apoptosis
Explanation: Apoptosis is a controlled process of cell death that eliminates damaged or
unnecessary cells, crucial for development and tissue maintenance.
Question 7: Which organelle packages and distributes proteins?
a) Lysosome
b) Mitochondrion
c) Golgi apparatus
d) Endoplasmic reticulum
Answer: c) Golgi apparatus
Explanation: The Golgi apparatus modifies, sorts, and packages proteins and lipids into
vesicles for secretion or cellular use.
Question 8: What is the primary energy currency of the cell?
a) Glucose
b) ATP
c) DNA
d) RNA
Answer: b) ATP
Explanation: Aden TP (adenosine triphosphate) provides energy for cellular processes
by releasing energy when its phosphate bonds are broken.
Question 9: Which type of cell lacks membrane-bound organelles?
a) Eukaryotic
b) Prokaryotic
c) Plant
d) Animal
Answer: b) Prokaryotic
Explanation: Prokaryotic cells, such as bacteria, lack membrane-bound organelles like
a nucleus, with DNA in a nucleoid region.
Question 10: What process divides the cytoplasm during cell division?
a) Mitosis
b) Meiosis
c) Cytokinesis
d) Interphase
Answer: c) Cytokinesis
Explanation: Cytokinesis follows mitosis, dividing the cytoplasm and organelles be-
tween daughter cells to complete cell division.
Question 11: Which organelle contains enzymes for intracellular digestion?
a) Peroxisome
b) Lysosome
c) Ribosome
d) Nucleus
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