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Cell Structure & Function Questions

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

Explanation:

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

Q. The cell theory was proposed by:
Schleiden and Schwann
Pasteur and Koch
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 lack a membrane-bound nucleus
Prokaryotes have mitochondria
Prokaryotes are always multicellular
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'?
Ribosome
Golgi apparatus
Mitochondria
Nucleus

Explanation:

Mitochondria generate ATP through oxidative phosphorylation.

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

Explanation:

Ribosomes synthesize proteins from amino acids using mRNA as template.

Q. The nucleus contains which genetic material?
Only RNA
Lipids
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?
Mitochondria
Ribosome
Golgi apparatus
Lysosome

Explanation:

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

Q. Lysosomes are known as:
Powerhouses
Suicide bags
Lipid factories
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 ribosomes attached
Being found only in prokaryotes
Having no membrane
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:
Plant cells and some algae
Animal cells only
Bacterial cells only
Fungal cells only

Explanation:

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

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

Explanation:

Chloroplasts perform photosynthesis, converting light energy into chemical energy.

Q. Which organelle is absent in animal cells?
Chloroplasts
Golgi apparatus
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:
Cellulose
Chitin
Phospholipid
Peptidoglycan

Explanation:

Plant cell walls are composed mainly of cellulose.

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

Explanation:

Bacterial cell walls are made of peptidoglycan (murein).

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

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
Nucleic acids, lipids, and proteins
Cellulose, chitin, and peptidoglycan

Explanation:

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

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

Explanation:

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

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

Explanation:

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

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

Explanation:

Peroxisomes break down fatty acids and detoxify hydrogen peroxide.

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

Explanation:

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

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

Explanation:

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

Q. The fluid mosaic model describes:
The structure of DNA
The structure of ribosomes
The structure of chloroplasts
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:
mRNA is translated on ribosomes
Ribosomes enter the nucleus
DNA enters the cytoplasm
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?
Cytoskeleton
Golgi apparatus
Lysosome
Nucleus

Explanation:

The cytoskeleton provides structural support and maintains cell shape.

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

Explanation:

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

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