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1. Who proposed the modification to cell theory stating "Omnis cellula-e-cellula"?
A. Rudolf Virchow
B. Matthias Schleiden
C. Theodore Schwann
D. Robert Brown
Answer: A. Rudolf Virchow
Explanation: Rudolf Virchow in 1855 first explained that cells divide and new cells are formed from pre-existing cells (Omnis cellula-e-cellula).
2. Which non-membrane-bound organelle is present in both prokaryotic and eukaryotic cells?
A. Ribosome
B. Lysosome
C. Peroxisome
D. Endoplasmic reticulum
Answer: A. Ribosome
Explanation: Ribosomes are non-membrane-bound organelles found in all living cells (70S in prokaryotes, 80S in eukaryotic cytoplasm).
3. According to the Fluid Mosaic Model, the lipid bilayer of the cell membrane is primarily composed of:
A. Phosphoglycerides
B. Sphingolipids
C. Triglycerides
D. Glycoproteins
Answer: A. Phosphoglycerides
Explanation: The cell membrane lipids are arranged in a bilayer made mainly of phosphoglycerides with polar heads facing outward.
4. Which organelle is key for the synthesis of lipids and steroidal hormones?
A. Smooth Endoplasmic Reticulum (SER)
B. Rough Endoplasmic Reticulum (RER)
C. Golgi Apparatus
D. Lysosome
Answer: A. Smooth Endoplasmic Reticulum (SER)
Explanation: The Smooth ER lacks ribosomes and serves as the major site for lipid and steroid hormone synthesis.
5. The main site for the formation of glycoproteins and glycolipids in eukaryotic cells is:
A. Golgi apparatus
B. Ribosome
C. Mitochondria
D. Plastid
Answer: A. Golgi apparatus
Explanation: Golgi apparatus receives proteins and lipids synthesized in the ER and modifies them into glycoproteins and glycolipids.
6. Hydrolytic enzymes active at acidic pH (lipases, proteases, carbohydrases) are enriched in:
A. Lysosomes
B. Vacuoles
C. Ribosomes
D. Peroxisomes
Answer: A. Lysosomes
Explanation: Lysosomes are membrane-bound vesicular structures formed by the Golgi apparatus containing hydrolytic enzymes optimal at acidic pH.
7. The inner membrane of mitochondria forms infoldings towards the matrix called:
A. Cristae
B. Thylakoids
C. Cisternae
D. Grana
Answer: A. Cristae
Explanation: Cristae increase the surface area of the inner mitochondrial membrane for ATP synthesis and electron transport enzymes.
8. What is the microtubule arrangement pattern in eukaryotic cilia and flagella core (axoneme)?
A. 9 + 2 arrangement
B. 9 + 0 arrangement
C. 8 + 2 arrangement
D. 9 + 1 arrangement
Answer: A. 9 + 2 arrangement
Explanation: The axoneme possesses nine doublets of radially arranged peripheral microtubules and a pair of centrally located microtubules (9+2 pattern).
9. Which region of a chromosome binds spindle fibers during cell division via proteinaceous structures?
A. Kinetochore at Centromere
B. Telomere
C. Chromocenter
D. Secondary constriction
Answer: A. Kinetochore at Centromere
Explanation: Disc-shaped structures called kinetochores are present on the primary constriction (centromere) where spindle fibers attach.
10. A chromosome with the centromere situated near one end resulting in one extremely short and one very long arm is termed:
A. Acrocentric
B. Metacentric
C. Sub-metacentric
D. Telocentric
Answer: A. Acrocentric
Explanation: In acrocentric chromosomes, the centromere is situated close to its end forming one extremely short and one very long arm.
11. Who first observed and described a live cell?
A. Anton von Leeuwenhoek
B. Robert Hooke
C. Robert Brown
D. Matthias Schleiden
Answer: A. Anton von Leeuwenhoek
Explanation: Anton von Leeuwenhoek first saw and described a living cell under a simple microscope. Robert Hooke observed dead cork cells.
12. The middle lamella of plant cell walls is mainly composed of which substance that glues neighbouring cells together?
A. Calcium pectate
B. Hemicellulose
C. Suberin
D. Lignin
Answer: A. Calcium pectate
Explanation: The middle lamella is a layer mainly made of calcium pectate which holds or glues the adjacent plant cells together.
13. Specialized membranous structure formed by infoldings of the plasma membrane in prokaryotes is called:
A. Mesosome
B. Chromatophore
C. Inclusion body
D. Plasmid
Answer: A. Mesosome
Explanation: Mesosomes are specialized infoldings of plasma membrane in bacteria that aid in cell wall formation, DNA replication, and respiration.
14. Extrachromosomal, small circular, double-stranded DNA found in many bacteria is known as:
A. Plasmid
B. Nucleoid
C. Cosmid
D. Genophore
Answer: A. Plasmid
Explanation: Plasmids are small, circular DNA molecules outside the main genomic DNA that confer unique phenotypic traits such as antibiotic resistance.
15. The Fluid Mosaic Model of cell membrane was proposed by Singer and Nicolson in which year?
A. 1972
B. 1950
C. 1965
D. 1982
Answer: A. 1972
Explanation: Singer and Nicolson proposed the widely accepted Fluid Mosaic Model of plasma membrane structure in 1972.
16. The membrane bound sac of plant cells that occupies up to 90% of cellular volume and stores water/ions is the:
A. Vacuole
B. Peroxisome
C. Glyoxysome
D. Lysosome
Answer: A. Vacuole
Explanation: The vacuole in plant cells is bound by a single membrane called tonoplast and can occupy up to 90% of total volume.
17. Single membrane surrounding the plant vacuole that facilitates transport against concentration gradients is called:
A. Tonoplast
B. Cytoplast
C. Symplast
D. Apoplast
Answer: A. Tonoplast
Explanation: Tonoplast is the semi-permeable membrane enclosing the plant vacuole, maintaining higher ion concentration inside.
18. Flattened membranous sacs stacked like coins inside the chloroplast stroma are termed:
A. Thylakoids
B. Cristae
C. Cisternae
D. Matrix
Answer: A. Thylakoids
Explanation: Thylakoids are disk-shaped membranous sacs arranged in stacks called grana within the chloroplast stroma.
19. Colourless plastids that store nutrients like carbohydrates, oils, and proteins in plant cells are:
A. Leucoplasts
B. Chromoplasts
C. Chloroplasts
D. Rhodoplasts
Answer: A. Leucoplasts
Explanation: Leucoplasts are non-pigmented plastids that include amyloplasts (starch), elaioplasts (fats/oils), and aleuroplasts (proteins).
20. The 70S prokaryotic ribosome consists of which two subunits?
A. 50S and 30S
B. 60S and 40S
C. 50S and 40S
D. 60S and 30S
Answer: A. 50S and 30S
Explanation: Prokaryotic 70S ribosomes are composed of a large 50S subunit and a small 30S subunit ('S' stands for Svedberg unit).
21. Microtubular organization of a centriole shows a pattern described as:
A. 9 + 0 arrangement
B. 9 + 2 arrangement
C. 8 + 2 arrangement
D. 9 + 1 arrangement
Answer: A. 9 + 0 arrangement
Explanation: Centrioles consist of nine evenly spaced peripheral triplets of tubulin microfilaments with no central microtubule (9+0 arrangement).
22. The spherical, dense, non-membrane bound region within the nucleus active in rRNA synthesis is:
A. Nucleolus
B. Chromatin
C. Nucleosome
D. Centrosome
Answer: A. Nucleolus
Explanation: The nucleolus is a site for active ribosomal RNA (rRNA) synthesis inside the nucleoplasm.
23. Nuclear envelope consists of two parallel membranes separated by a space called:
A. Perinuclear space
B. Perimitochondrial space
C. Intercristal space
D. Cytoplasmic cleft
Answer: A. Perinuclear space
Explanation: The outer and inner membranes of the nucleus are separated by a 10–50 nm perinuclear space forming a barrier between nuclear materials and cytoplasm.
24. Non-staining secondary constrictions on certain chromosomes leave a small fragment called:
A. Satellite
B. Kinetochore
C. Telomere
D. Chromatid
Answer: A. Satellite
Explanation: A few chromosomes have non-staining secondary constrictions at a constant location, giving the appearance of a small fragment termed a satellite (SAT chromosome).
25. Basic proteins associated with eukaryotic DNA in chromatin are called:
A. Histones
B. Prolamins
C. Globulins
D. Albumin
Answer: A. Histones
Explanation: Chromatin contains genomic DNA wrapped around basic, positively charged proteins rich in lysine and arginine called histones.
This page contains a chapter-wise objective practice set. Try the questions without checking the answer first, then use the explanation to understand the point you missed. The current page contains 25 questions, so you can practise in smaller sets when you are revising.
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