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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
Robert Brown
Anton van Leeuwenhoek
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
Schleiden and Schwann
Pasteur and Koch

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

Explanation:

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

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

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
Only RNA
DNA
Lipids

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

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
Plant cells and some algae
Animal cells only

Explanation:

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

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

Explanation:

Chloroplasts perform photosynthesis, converting light energy into chemical energy.

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

Explanation:

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

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

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
Lignin
Peptidoglycan
Cellulose

Explanation:

Fungal cell walls contain chitin, distinguishing them from plants.

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

Explanation:

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

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

Explanation:

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

Q. The nucleolus is the site of:
Lipid synthesis
DNA replication
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:
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
Plant cells
Fungal cells only
Animal cells

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 the cell membrane
The structure of ribosomes
The structure of DNA
The structure of chloroplasts

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
DNA enters the cytoplasm
mRNA is translated on ribosomes
The cell divides

Explanation:

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

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