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TestMaster MCQs

Cell Structure & Function Questions

Home Science Cell Structure & Function
Q. Which scientist first observed cells in 1665 using a microscope?
Robert Hooke
Anton van Leeuwenhoek
Robert Brown
Matthias Schleiden

Explanation:

Robert Hooke observed cork cells in 1665, coining the term 'cell'.

Q. The cell theory was proposed by:
Pasteur and Koch
Schleiden and Schwann
Hooke and Leeuwenhoek
Watson and Crick

Explanation:

Schleiden and Schwann (1838–39) formulated cell theory; Virchow later added 'omnis cellula e cellula'.

Q. Which of the following is a key feature distinguishing prokaryotes from eukaryotes?
Prokaryotes have a nuclear envelope
Prokaryotes lack a membrane-bound nucleus
Prokaryotes have mitochondria
Prokaryotes are always multicellular

Explanation:

Prokaryotes lack a membrane-bound nucleus; eukaryotes have one.

Q. Which organelle is known as the 'powerhouse of the cell'?
Ribosome
Mitochondria
Golgi apparatus
Nucleus

Explanation:

Mitochondria generate ATP through oxidative phosphorylation.

Q. The site of protein synthesis in a cell is the:
Nucleus
Ribosome
Lysosome
Golgi apparatus

Explanation:

Ribosomes synthesize proteins from amino acids using mRNA as template.

Q. The nucleus contains which genetic material?
Lipids
Only RNA
Proteins only
DNA

Explanation:

The nucleus houses the cell's DNA, which contains the genetic code.

Q. Which organelle is responsible for packaging and modifying proteins?
Lysosome
Golgi apparatus
Mitochondria
Ribosome

Explanation:

The Golgi apparatus modifies, sorts, and packages proteins from the ER.

Q. Lysosomes are known as:
Powerhouses
Lipid factories
Suicide bags
Protein factories

Explanation:

Lysosomes contain digestive enzymes and are the cell's 'suicide bags' or garbage disposal system.

Q. The rough endoplasmic reticulum differs from smooth ER by:
Having no membrane
Being found only in prokaryotes
Having ribosomes attached
Producing ATP

Explanation:

Rough ER has ribosomes attached for protein synthesis; smooth ER lacks ribosomes and is involved in lipid synthesis.

Q. Chloroplasts are found in:
Fungal cells only
Bacterial cells only
Animal cells only
Plant cells and some algae

Explanation:

Chloroplasts occur in plant cells and some algae — not in animal cells.

Q. Chloroplasts are the site of:
Protein synthesis
Lipid breakdown
Cellular respiration
Photosynthesis

Explanation:

Chloroplasts perform photosynthesis, converting light energy into chemical energy.

Q. Which organelle is absent in animal cells?
Golgi apparatus
Chloroplasts
Ribosomes
Mitochondria

Explanation:

Chloroplasts are absent in animal cells; mitochondria are present in both.

Q. The cell wall of plant cells is primarily made of:
Phospholipid
Peptidoglycan
Cellulose
Chitin

Explanation:

Plant cell walls are composed mainly of cellulose.

Q. The cell wall of bacteria is primarily made of:
Peptidoglycan
Cellulose
Chitin
Lignin

Explanation:

Bacterial cell walls are made of peptidoglycan (murein).

Q. Fungal cell walls are mainly composed of:
Lignin
Peptidoglycan
Chitin
Cellulose

Explanation:

Fungal cell walls contain chitin, distinguishing them from plants.

Q. The cytoskeleton is made up of which three main components?
Microfilaments, intermediate filaments, and microtubules
Cellulose, chitin, and peptidoglycan
Ribosomes, lysosomes, and vacuoles
Nucleic acids, lipids, and proteins

Explanation:

The cytoskeleton consists of microfilaments, intermediate filaments, and microtubules.

Q. Which of the following is NOT membrane-bound?
Ribosome
Golgi apparatus
Mitochondria
Nucleus

Explanation:

Ribosomes are non-membrane-bound organelles found free or attached to ER.

Q. The nucleolus is the site of:
DNA replication
Lipid synthesis
rRNA synthesis and ribosome assembly
ATP production

Explanation:

The nucleolus is where ribosomal RNA (rRNA) is synthesized and ribosome assembly begins.

Q. Peroxisomes function primarily to:
Break down fatty acids and detoxify
Produce ATP
Store water
Synthesize proteins

Explanation:

Peroxisomes break down fatty acids and detoxify hydrogen peroxide.

Q. The central vacuole is found predominantly in:
Animal cells
Plant cells
Bacterial cells
Fungal cells only

Explanation:

Plant cells have large central vacuoles for storage, turgor, and waste management.

Q. Which organelle modifies proteins with carbohydrate chains?
Nucleus
Mitochondria
Ribosome
Golgi apparatus

Explanation:

The Golgi apparatus performs glycosylation — adding carbohydrate chains to proteins.

Q. The fluid mosaic model describes:
The structure of DNA
The structure of chloroplasts
The structure of the cell membrane
The structure of ribosomes

Explanation:

The fluid mosaic model (Singer & Nicolson, 1972) describes the cell membrane as a fluid phospholipid bilayer with embedded proteins.

Q. Protein synthesis begins in the cytoplasm when:
mRNA is translated on ribosomes
Ribosomes enter the nucleus
The cell divides
DNA enters the cytoplasm

Explanation:

Translation begins on free ribosomes; proteins destined for secretion move to the ER.

Q. Which cellular component is responsible for maintaining cell shape?
Cytoskeleton
Lysosome
Nucleus
Golgi apparatus

Explanation:

The cytoskeleton provides structural support and maintains cell shape.

Q. The endosymbiotic theory explains the origin of:
Golgi and ER
Nucleus and ribosomes
Mitochondria and chloroplasts
Cell wall and membrane

Explanation:

The endosymbiotic theory proposes that mitochondria and chloroplasts evolved from engulfed prokaryotes.

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