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Cell Structure & Function Questions

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

Explanation:

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

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

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 are always multicellular
Prokaryotes have mitochondria
Prokaryotes lack a membrane-bound nucleus

Explanation:

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

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

Explanation:

Mitochondria generate ATP through oxidative phosphorylation.

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

Explanation:

Ribosomes synthesize proteins from amino acids using mRNA as template.

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

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:
Lipid factories
Protein factories
Suicide bags
Powerhouses

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:
Producing ATP
Having no membrane
Having ribosomes attached
Being found only in prokaryotes

Explanation:

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

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

Explanation:

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

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

Explanation:

Chloroplasts perform photosynthesis, converting light energy into chemical energy.

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

Explanation:

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

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

Explanation:

Plant cell walls are composed mainly of cellulose.

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

Explanation:

Bacterial cell walls are made of peptidoglycan (murein).

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

Explanation:

Fungal cell walls contain chitin, distinguishing them from plants.

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

Explanation:

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

Q. The nucleolus is the site of:
DNA replication
rRNA synthesis and ribosome assembly
Lipid synthesis
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
Synthesize proteins
Store water

Explanation:

Peroxisomes break down fatty acids and detoxify hydrogen peroxide.

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

Explanation:

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

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

Explanation:

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

Q. The fluid mosaic model describes:
The structure of chloroplasts
The structure of DNA
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:
Ribosomes enter the nucleus
The cell divides
DNA enters the cytoplasm
mRNA is translated on ribosomes

Explanation:

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

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

Explanation:

The cytoskeleton provides structural support and maintains cell shape.

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

Explanation:

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

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