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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
Watson and Crick
Hooke and Leeuwenhoek

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 mitochondria
Prokaryotes have a nuclear envelope
Prokaryotes are always multicellular
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'?
Golgi apparatus
Ribosome
Nucleus
Mitochondria

Explanation:

Mitochondria generate ATP through oxidative phosphorylation.

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

Explanation:

Ribosomes synthesize proteins from amino acids using mRNA as template.

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

Explanation:

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

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

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:
Having no membrane
Having ribosomes attached
Producing ATP
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:
Animal cells only
Bacterial cells only
Fungal 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:
Cellular respiration
Protein synthesis
Photosynthesis
Lipid breakdown

Explanation:

Chloroplasts perform photosynthesis, converting light energy into chemical energy.

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

Explanation:

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

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

Explanation:

Plant cell walls are composed mainly of cellulose.

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

Explanation:

Bacterial cell walls are made of peptidoglycan (murein).

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

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
Ribosomes, lysosomes, and vacuoles
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
Nucleus
Golgi apparatus
Mitochondria

Explanation:

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

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

Explanation:

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

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

Explanation:

Peroxisomes break down fatty acids and detoxify hydrogen peroxide.

Q. The central vacuole is found predominantly in:
Plant cells
Bacterial cells
Animal 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?
Golgi apparatus
Nucleus
Mitochondria
Ribosome

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 ribosomes
The structure of the cell membrane

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:
The cell divides
mRNA is translated on ribosomes
DNA enters the cytoplasm
Ribosomes enter the nucleus

Explanation:

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

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

Explanation:

The cytoskeleton provides structural support and maintains cell shape.

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

Explanation:

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

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