Cell Biology – NDA Biology PYQs

NDA 2026-I

Q. 1. Consider the following statements in respect of cell and its structure:

I. All cells possess cell wall.

II. All cells have ribosomes present inside.

III. All cells have well-organized nucleus.

IV. All cells have linear DNA molecules present in them.

Which of the statements given above is/are correct?

(a) II and III

(b) II only

(c) II and IV

(d) I and III

Answer: (b) II only

Explanation: Ribosomes are present in all cells: both prokaryotic and eukaryotic. This makes Statement II universally correct. Cell walls are absent in animal cells, so Statement I is wrong. Prokaryotes lack a well-organized nucleus, so Statement III is wrong. Prokaryotes have circular DNA, not linear, so Statement IV is wrong. Concept Tested: Universal cell structures vs. cell-type-specific structures

★ JOVIK Exam Insight NDA frequently asks which structures are present in ALL cells. Only ribosomes and the plasma membrane qualify universally. Cell walls, organized nucleus, and linear DNA do not.

NDA 2025-II

Q. 2. Which of the following organelles have their own DNA and ribosomes?

(a) Endoplasmic reticulum and Golgi bodies

(b) Mitochondria and Chloroplast

(c) Endoplasmic reticulum and cytoskeleton

(d) Cell wall and nucleolus

Answer: (b) Mitochondria and Chloroplast

Explanation: Mitochondria and chloroplasts are semi-autonomous organelles. Both contain their own circular DNA and ribosomes. This supports the endosymbiotic theory of their origin. No other organelle among the options has its own genetic machinery. Concept Tested: Semi-autonomous organelles with own DNA and ribosomes

★ JOVIK Exam Insight The pair “mitochondria and chloroplast” is the most repeated answer in NDA for questions about organelles with their own genetic material. This concept has appeared in multiple papers.

NDA 2025-I

Q. 3. The lactic acid that gets accumulated in the muscle cells during rigorous exercise causing muscle cramps is produced from

(a) ATP

(b) Pyruvate

(c) Ethanol

(d) Glucose

Answer: (b) Pyruvate

Explanation: During intense exercise, oxygen supply to muscles becomes insufficient. Cells shift to anaerobic respiration. In this process, pyruvate (produced from glucose via glycolysis) is converted to lactic acid instead of entering the mitochondria. The accumulated lactic acid causes the sensation of muscle cramps. Concept Tested: Anaerobic respiration: pyruvate to lactic acid conversion in muscle cells

NDA 2024-II

Q. 4. Which one of the following statements about lysosomes is NOT correct?

(a) They are waste disposal system of the cell

(b) They breakdown all inorganic materials

(c) These are also referred to as “suicidal bags”

(d) Lysosomes stop entry of foreign materials

Answer: (b) They breakdown all inorganic materials

Explanation: Lysosomes are membrane-bound organelles containing hydrolytic enzymes. They digest old organelles, food particles, and foreign bodies. They do NOT break down inorganic materials such as minerals. Option (b) is also incorrect because they do not stop entry: they digest foreign materials after they enter. However, the primary false statement here is (b): lysosomes break down organic, not inorganic, materials. Concept Tested: Functions and limitations of lysosomes

Q. 5. Which of the following two cell organelles have their own genetic material?

(a) Endoplasmic reticulum and plastids

(b) Endoplasmic reticulum and mitochondria

(c) Mitochondria and plastids

(d) Lysosomes and Golgi apparatus

Answer: (c) Mitochondria and plastids

Explanation: Mitochondria and plastids (including chloroplasts) are semi-autonomous organelles. Both contain their own DNA and ribosomes. Endoplasmic reticulum, Golgi apparatus, and lysosomes do not have their own genetic material. Concept Tested: Organelles containing their own genetic material

Q. 6. Which one among the following is the source of energy in cells?

(a) ADP

(b) ATP

(c) AMP

(d) NAD

Answer: (b) ATP

Explanation: ATP (Adenosine Triphosphate) is the primary energy currency of the cell. Energy stored in the phosphate bonds of ATP is released when one phosphate group is removed, converting ATP to ADP. This energy powers cellular processes. ADP, AMP, and NAD are not direct energy sources in the same sense. Concept Tested: ATP as the energy currency of cells

NDA 2024-I

Q. 7. Which of the following statements regarding animal cell membrane is correct?

(a) They are composed of phospholipids only.

(b) They are composed of proteins only.

(c) They are composed of phospholipids and proteins only.

(d) They are composed of phospholipids, proteins and cholesterol (lipid).

Answer: (d) They are composed of phospholipids, proteins and cholesterol (lipid).

Explanation: Animal cell membranes are made of a phospholipid bilayer embedded with proteins. In addition, animal cell membranes contain cholesterol, which is absent in plant cell membranes. Cholesterol helps stabilise membrane fluidity. The correct composition is phospholipids, proteins, and cholesterol. Concept Tested: Composition of animal cell membrane including cholesterol

Q. 8. Which of the following is not a part of compound microscope?

(a) Mirror

(b) Stage

(c) Clip

(d) Retina

Answer: (d) Retina

Explanation: A compound microscope consists of parts such as eyepiece, objective lens, stage, clips, mirror, and arm. The retina is part of the human eye, not the microscope. It is the biological structure that receives light and sends signals to the brain. Concept Tested: Parts of a compound microscope

Q. 9. Which one of the following is the correct sequence in increasing complexity?

(a) Protein – Organism – Tissue – Organ

(b) Protein – Organ – Tissue – Organism

(c) Protein – Organism – Organ – Tissue

(d) Protein – Tissue – Organ – Organism

Answer: (d) Protein – Tissue – Organ – Organism

Explanation: The hierarchy of biological organisation from least to most complex is: Molecule → Cell → Tissue → Organ → Organ System → Organism. Among the options, Protein → Tissue → Organ → Organism represents the correct increasing order of complexity. Concept Tested: Hierarchy of biological organisation

Q. 10. Consider the following statements:

1. DNA replication takes place when chromatin is opened up.

2. Chromatin organises itself into rod-shaped chromosomes before cell division.

3. Both prokaryotes and eukaryotes have the same process for cell division.

Which of the statements given above is/are correct?

(a) 1 only

(b) 1 and 2 only

(c) 1, 2 and 3

(d) 3 only

Answer: (b) 1 and 2 only

Explanation: Statement 1 is correct: DNA replication occurs when chromatin is in its unwound form. Statement 2 is correct: chromatin condenses into rod-shaped chromosomes before cell division begins. Statement 3 is incorrect: prokaryotes divide by binary fission while eukaryotes undergo mitosis or meiosis: these are different processes. Concept Tested: DNA replication, chromatin condensation, and differences in cell division between prokaryotes and eukaryotes

Q. 11. In most prokaryotes, the chromosome number is:

(a) 4

(b) 3

(c) 2

(d) 1

Answer: (d) 1

Explanation: Most prokaryotes have a single circular chromosome. They are haploid organisms. This single chromosome is found in the nucleoid region of the cell, which is not enclosed by a membrane. Concept Tested: Chromosome number in prokaryotes

Q. 12. Bacterial DNA is referred to as naked because it is not associated with:

(a) any scaffold

(b) proteins

(c) ribozymes

(d) plasmid

Answer: (b) proteins

Explanation: In eukaryotes, DNA is tightly wound around histone proteins to form chromatin. Bacterial DNA lacks these histone proteins. It is therefore called “naked DNA.” It is not associated with proteins in the structural sense that eukaryotic chromosomal DNA is. Concept Tested: Naked DNA in bacteria: absence of histone proteins

NDA 2023-II

Q. 13. Eukaryotic cells are much more complex as compared to prokaryotes. Which one of the following structures is exclusively present in a eukaryotic cell?

(a) Cell wall

(b) Plasma membrane

(c) Nucleic acid

(d) Mitochondria

Answer: (d) Mitochondria

Explanation: Mitochondria are membrane-bound organelles found only in eukaryotic cells. Prokaryotes lack membrane-bound organelles. Cell walls are present in both prokaryotes (bacteria) and eukaryotes (plants, fungi). Plasma membranes and nucleic acids are universal to all cells. Concept Tested: Structures exclusive to eukaryotic cells

★ JOVIK Exam Insight A common NDA trap is selecting “cell wall” as eukaryote-exclusive. Cell walls exist in bacteria (prokaryotes) too. Only mitochondria and membrane-bound organelles are exclusively eukaryotic.

NDA 2023-I

Q. 14. Consider the following statements regarding cell wall composition:

1. Bacterial cell wall is made of peptidoglycan.

2. Fungal cell wall is made of cellulose.

3. Animals lack cell wall and have extracellular matrix made up of sugar and proteins.

Select the correct answer using the code given below:

(a) 2 only

(b) 1 and 2 only

(c) 1 and 3 only

(d) 1, 2 and 3

Answer: (c) 1 and 3 only

Explanation: Statement 1 is correct: bacterial cell walls are composed of peptidoglycan (also called murein). Statement 2 is incorrect: fungal cell walls are made of chitin, not cellulose (cellulose is found in plant cell walls). Statement 3 is correct: animal cells lack a cell wall and instead have an extracellular matrix made of proteins and polysaccharides (sugars). Concept Tested: Cell wall composition: peptidoglycan in bacteria, chitin in fungi, extracellular matrix in animals

★ JOVIK Exam Insight Fungal cell wall = chitin; Plant cell wall = cellulose. NDA has tested this distinction repeatedly. Do not confuse the two.

Q. 15. Which one of the following structures is not present in a prokaryotic cell?

(a) Cell wall

(b) Ribosomes

(c) Nucleus

(d) Plasma membrane

Answer: (c) Nucleus

Explanation: Prokaryotic cells lack a membrane-bound nucleus. Their genetic material lies in the cytoplasm in a region called the nucleoid. Ribosomes, cell walls, and plasma membranes are all present in prokaryotic cells. Concept Tested: Absence of membrane-bound nucleus in prokaryotes

Q. 16. In a plant cell, which one of the following contains their own DNA?

(a) Nucleus and Endoplasmic Reticulum

(b) Ribosome and Golgi apparatus

(c) Mitochondria and Chloroplast

(d) Chloroplast and Vacuoles

Answer: (c) Mitochondria and Chloroplast

Explanation: In plant cells, both mitochondria and chloroplasts contain their own DNA and ribosomes. These organelles are considered semi-autonomous due to their ability to self-replicate to some extent. Endoplasmic reticulum, Golgi apparatus, ribosomes, and vacuoles do not contain DNA. Concept Tested: DNA-containing organelles in plant cells: mitochondria and chloroplasts

Q. 17. Which one of the following structures or components is not always present in living cells?

(a) Cell wall

(b) Plasma membrane

(c) Cytoplasm

(d) Genetic material

Answer: (a) Cell wall

Explanation: Cell walls are not present in all living cells. Animal cells completely lack cell walls. Plasma membrane, cytoplasm, and genetic material are present in all living cells. The cell wall is a feature of plant cells, fungi, and bacteria, but not animal cells. Concept Tested: Cell wall as a non-universal cell component

Q. 18. When yeast cells are O₂ starved, fermentation serves as the source of energy. This results in the production of:

(a) ATP + CO₂ + Ethanol

(b) ATP + O₂ + Pyruvate

(c) ATP + CO₂ + Lactic acid

(d) ATP + O₂ + Acetaldehyde

Answer: (a) ATP + CO₂ + Ethanol

Explanation: In yeast, anaerobic respiration (fermentation) converts glucose to pyruvate (glycolysis), which is then converted to ethanol and CO₂. This process also produces a small amount of ATP. Lactic acid fermentation occurs in animal muscle cells, not yeast. Yeast produces ethanol, not lactic acid. Concept Tested: Anaerobic fermentation in yeast: products are ethanol, CO₂, and ATP

NDA 2022-II

Q. 19. Which one of the following statements about animal cells and plant cells is correct?

(a) Animal cells have only cell membrane not cell wall, whereas plant cells have only cell wall not cell membrane.

(b) Animal cells have only cell membrane not cell wall, but plant cells have both.

(c) Both animal and plant cells have cell membrane and cell wall.

(d) Only some cells of animals have cell wall and all plant cells have cell membrane.

Answer: (b) Animal cells have only cell membrane not cell wall, but plant cells have both.

Explanation: Animal cells possess only the cell membrane (plasma membrane) and do not have a cell wall. Plant cells have both a cell membrane and a cell wall outside it. Option (a) is wrong because plant cells also have a cell membrane. Option (c) is wrong because animal cells have no cell wall. Concept Tested: Difference between animal cells and plant cells regarding cell wall and cell membrane

Q. 20. The breakdown of glucose in cytoplasm results in the formation of

(a) pyruvate and energy

(b) pyruvate and carbon dioxide

(c) pyruvate and oxygen

(d) pyruvate and nitrogen

Answer: (a) pyruvate and energy

Explanation: Glycolysis is the process of glucose breakdown that occurs in the cytoplasm. One glucose molecule is broken down into two pyruvate molecules. This process also releases energy in the form of ATP. Carbon dioxide is not produced during glycolysis: it is produced in later stages inside the mitochondria. Concept Tested: Glycolysis: glucose breakdown in cytoplasm produces pyruvate and energy

Q. 21. Which one of the following will be resulted when an animal cell is surrounded by a medium with lower concentration of water?

(a) Cell will lose water

(b) No change in movement of water

(c) Cell will gain water

(d) Cell will swell up

Answer: (a) Cell will lose water

Explanation: A medium with lower water concentration is a hypertonic solution (higher solute concentration outside). By osmosis, water moves from higher water concentration (inside the cell) to lower water concentration (outside). The cell therefore loses water and shrinks: a process called plasmolysis in plants, and crenation in animal cells. Concept Tested: Osmosis in animal cells: water loss in hypertonic medium

Q. 22. The digestive enzymes are present in

(a) mitochondria

(b) vacuoles

(c) lysosomes

(d) ribosomes

Answer: (c) lysosomes

Explanation: Lysosomes are membrane-bound organelles that contain powerful hydrolytic (digestive) enzymes. These enzymes can break down proteins, lipids, carbohydrates, and nucleic acids. This is why lysosomes are called the “digestive bags” or “suicidal bags” of the cell. Concept Tested: Lysosomes as the site of digestive enzymes in the cell

NDA 2022-I

Q. 23. Which of the following statements about living and non-living being is/are correct?

1. While living being can demonstrate growth and repair, non-living being cannot.

2. While living being demonstrates metabolic processes, non-living being does not.

Select the correct answer using the code given below.

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2

Answer: (c) Both 1 and 2

Explanation: Both statements are correct. Living organisms can grow and repair damaged tissues. Non-living things cannot repair themselves. Living organisms carry out metabolic processes such as respiration, digestion, and excretion. Non-living things do not perform metabolism. Concept Tested: Characteristics that distinguish living from non-living: growth, repair, and metabolism

Q. 24. Which one of the following plant plastids stores starch, oil and protein granules?

(a) Chloroplast

(b) Leucoplast

(c) Chromoplast

(d) Xanthoplast

Answer: (b) Leucoplast

Explanation: Leucoplasts are colourless plastids found mainly in non-green parts of plants such as roots, seeds, and tubers. They serve as storage organelles. There are three types: amyloplasts (store starch), elaioplasts (store oils/fats), and aleuroplasts (store proteins). Collectively, leucoplasts store starch, oil, and protein granules. Concept Tested: Leucoplasts as storage plastids for starch, oil, and proteins

Q. 25. Which one of the following statements about ‘vacuoles’ is not correct?

(a) In plants, there is a large central vacuole that may occupy 90% of total cell volume.

(b) In plant cells, vacuoles provide turgidity and rigidity.

(c) In Amoeba, vacuoles have role in nutrition.

(d) Vacuoles are absent in animal cells.

Answer: (d) Vacuoles are absent in animal cells.

Explanation: Vacuoles are not absent in animal cells. They are present but are small and temporary. In plant cells, the central vacuole is large and prominent. In Amoeba, food vacuoles help in digestion. Option (d) is incorrect because animal cells do have vacuoles, though they are much smaller than in plant cells. Concept Tested: Vacuoles: presence in animal cells, differences from plant cell vacuoles

Q. 26. A cell is unable to synthesize lipids. Which of its cell organelles might be defective?

(a) Smooth endoplasmic reticulum

(b) Golgi bodies

(c) Lysosomes

(d) Mitochondria

Answer: (a) Smooth endoplasmic reticulum

Explanation: The smooth endoplasmic reticulum (SER) is the site of lipid synthesis. It also plays a role in detoxification and carbohydrate metabolism. Rough endoplasmic reticulum (RER) is associated with protein synthesis. If lipid synthesis fails, the SER is most likely defective. Concept Tested: Smooth endoplasmic reticulum as the site of lipid synthesis

NDA 2021-I

Q. 27. Movement of materials to different parts of cytoplasm and nucleus is generally carried out by

(a) Ribosomes.

(b) Mitochondria.

(c) Lysosomes.

(d) Endoplasmic reticulum.

Answer: (d) Endoplasmic reticulum.

Explanation: The endoplasmic reticulum (ER) is an interconnected network of membranes extending from the nuclear membrane through the cytoplasm. It acts as a transport system within the cell, moving materials between different cellular compartments and to the cell membrane. Ribosomes synthesise proteins; mitochondria produce energy; lysosomes digest material. Concept Tested: Endoplasmic reticulum as the intracellular transport system

Q. 28. In mitochondria, ATP synthesizing chemical reactions take place in the

(a) Outer membrane.

(b) Matrix.

(c) Inner membrane.

(d) DNA of mitochondria.

Answer: (c) Inner membrane.

Explanation: The inner mitochondrial membrane is the site of the electron transport chain and ATP synthesis. The enzyme ATP synthase is embedded in the inner membrane. The matrix contains enzymes for the Krebs cycle. The outer membrane is permeable and mainly acts as a boundary. DNA does not directly synthesize ATP. Concept Tested: Inner mitochondrial membrane as the site of ATP synthesis

Q. 29. If human blood is placed in a 2% detergent solution, what will happen to the RBC?

(a) The RBC will shrink.

(b) The RBC will swell and become turgid.

(c) The RBC will swell and burst.

(d) The RBC will lyse.

Answer: (d) The RBC will lyse.

Explanation: Detergents disrupt lipid bilayers. The cell membrane of RBCs is made of a phospholipid bilayer. A detergent solution will dissolve the membrane, causing cell contents to spill out. This process is called lysis. Options (c) and (d) are closely related, but lysis specifically means membrane rupture and cell death due to chemical disruption, which is the most accurate answer here. Concept Tested: Effect of detergents on cell membranes: membrane lysis

NDA 2020

Q. 30. Which one of the following cell organelles may play a role in expelling excess water and wastes in case of unicellular organisms?

(a) Lysosome

(b) Vacuole

(c) Golgi body

(d) Endoplasmic reticulum

Answer: (b) Vacuole

Explanation: In unicellular organisms such as Amoeba and Paramecium, contractile vacuoles regulate the water content of the cell. They collect excess water from the cytoplasm and expel it outside the cell. This process is called osmoregulation. Lysosomes digest waste; Golgi bodies package materials; ER is a transport network. Concept Tested: Contractile vacuole in unicellular organisms: osmoregulation and waste expulsion

Q. 31. In prokaryotic organisms, nuclear region is not surrounded by a membrane. This undefined nuclear region is known as

(a) Nucleic acid

(b) Nucleoid

(c) Nucleolus

(d) Nucleosome

Answer: (b) Nucleoid

Explanation: In prokaryotes, there is no membrane-bound nucleus. The genetic material is concentrated in a region of the cytoplasm called the nucleoid. This is not enclosed by any membrane. The nucleolus is a structure inside the eukaryotic nucleus. Nucleosomes are DNA–histone complexes found in eukaryotes. Concept Tested: Nucleoid: the undefined nuclear region in prokaryotic cells

NDA 2019-II

Q. 32. Net movement of water from a dilute to a concentrated solution through a selectively permeable membrane is called

(a) Diffusion

(b) Dispersion

(c) Osmosis

(d) Absorption

Answer: (c) Osmosis

Explanation: Osmosis is the movement of water molecules from a region of higher water concentration (dilute solution) to lower water concentration (concentrated solution) through a selectively permeable membrane. Diffusion is the movement of any substance from higher to lower concentration, but does not require a membrane. Absorption involves intake of substances by cells or roots. Concept Tested: Definition and mechanism of osmosis through a selectively permeable membrane

Q. 33. Mitochondria are able to produce their own

(a) Nucleus

(b) Proteins

(c) Chloroplasts

(d) Digestive enzymes

Answer: (b) Proteins

Explanation: Mitochondria contain their own DNA and ribosomes. They use this machinery to produce some of their own proteins. However, they are not fully self-sufficient: many mitochondrial proteins are encoded by nuclear DNA. Mitochondria cannot produce a nucleus, chloroplasts, or digestive enzymes. Concept Tested: Mitochondria as semi-autonomous organelles capable of producing their own proteins

NDA 2019-I

Q. 34. Which one of the following cell organelles does NOT possess nucleic acid?

(a) Nucleolus

(b) Chloroplast

(c) Ribosome

(d) Plasma Membrane

Answer: (d) Plasma Membrane

Explanation: The plasma membrane is made of phospholipids, proteins, and cholesterol. It does not contain nucleic acids. The nucleolus is inside the nucleus and contains rRNA. Chloroplasts contain their own DNA. Ribosomes are made of rRNA (a nucleic acid) and proteins. Concept Tested: Plasma membrane as a cell structure lacking nucleic acid

Q. 35. Which one of the following cell organelles does NOT possess its own genetic material encoding proteins?

(a) Ribosome

(b) Nucleus

(c) Mitochondria

(d) Chloroplast

Answer: (a) Ribosome

Explanation: Ribosomes are made of rRNA and proteins, but they do not possess their own genetic material (DNA) that encodes proteins independently. The nucleus contains chromosomal DNA. Mitochondria and chloroplasts each have their own circular DNA that encodes some proteins. Concept Tested: Ribosomes lack their own DNA; nucleus, mitochondria, and chloroplasts have DNA

Q. 36. Which one of the following organelles of mammalian cell is rich in hydrolytic enzymes?

(a) Mitochondria

(b) Ribosomes

(c) Lysosome

(d) Nucleus

Answer: (c) Lysosome

Explanation: Lysosomes contain a large variety of hydrolytic enzymes such as proteases, lipases, and nucleases. These enzymes are active at an acidic pH maintained inside the lysosome. They break down macromolecules, old organelles, and foreign particles engulfed by the cell. Concept Tested: Lysosomes: rich in hydrolytic enzymes, function as digestive organelles

NDA 2018-II

Q. 37. Which one of the following groups of cellular organelles contains DNA?

(a) Mitochondria, nucleus, chloroplast

(b) Mitochondria, Golgi bodies, nucleus

(c) Mitochondria, plasma membrane, nucleus

(d) Chloroplast, nucleus, ribosomes

Answer: (a) Mitochondria, nucleus, chloroplast

Explanation: Among all organelles, only mitochondria, nucleus, and chloroplasts contain DNA. Golgi bodies, plasma membrane, and ribosomes do not have their own DNA. Ribosomes contain rRNA but not DNA. Concept Tested: DNA-containing organelles: mitochondria, nucleus, and chloroplast

Q. 38. One of the additional functions of Smooth Endoplasmic Reticulum (SER) is

(a) protein synthesis

(b) lipid synthesis

(c) storage of biomolecules

(d) detoxification of toxic substances

Answer: (d) detoxification of toxic substances

Explanation: The smooth endoplasmic reticulum (SER) is primarily known for lipid synthesis. Its additional functions include detoxification of drugs and toxic substances, especially in liver cells. Protein synthesis is carried out by ribosomes attached to the rough ER (RER). Storage is a general function, not specific to SER. Concept Tested: Additional function of SER: detoxification of toxic substances

NDA 2018-I

Q. 39. Which one of the following is an organelle that is NOT found in prokaryotic cells?

(a) Cell wall

(b) Mitochondria

(c) Plasma membrane

(d) Ribosome

Answer: (b) Mitochondria

Explanation: Prokaryotic cells lack membrane-bound organelles. Mitochondria are membrane-bound organelles found only in eukaryotic cells. Cell walls, plasma membranes, and ribosomes are all present in prokaryotic cells, though prokaryotic ribosomes are smaller (70S) than eukaryotic ribosomes (80S). Concept Tested: Mitochondria as a eukaryote-exclusive membrane-bound organelle

Q. 40. Who among the following first discovered cell?

(a) Robert Brown

(b) Robert Hooke

(c) Leeuwenhoek

(d) Rudolf Virchow

Answer: (b) Robert Hooke

Explanation: Robert Hooke first observed and named the cell in 1665 while examining a thin slice of cork under a microscope. He described the box-like structures as “cells.” Robert Brown discovered the nucleus. Leeuwenhoek was the first to observe living microorganisms. Rudolf Virchow proposed that all cells arise from pre-existing cells. Concept Tested: Discovery of the cell by Robert Hooke in 1665

NDA 2017-I

Q. 41. Cell wall of any fungus is different from plants in having

(a) cellulose

(b) chitin

(c) cholesterol

(d) glycogen

Answer: (b) chitin

Explanation: Plant cell walls are made of cellulose. Fungal cell walls are made of chitin, which is a nitrogen-containing polysaccharide. Cholesterol is found in animal cell membranes. Glycogen is the storage carbohydrate in animals and fungi, but it is not a component of the fungal cell wall. Concept Tested: Chitin as the structural component of fungal cell walls (vs. cellulose in plants)

NDA 2016-II

Q. 42. The genetic material of bacteria is found in

(a) nucleus

(b) cytoplasm

(c) cell membrane

(d) ribosome

Answer: (b) cytoplasm

Explanation: Bacteria are prokaryotes and do not have a membrane-bound nucleus. Their genetic material (a single circular chromosome) is found in the cytoplasm, concentrated in a region called the nucleoid. It is not enclosed within a nuclear membrane. Concept Tested: Location of bacterial genetic material: cytoplasm (nucleoid region)

NDA 2015-II

Q. 43. Muscle fatigue is due to the accumulation of:

(a) Cholesterol

(b) Lactic acid

(c) Lipoic acid

(d) Triglycerides

Answer: (b) Lactic acid

Explanation: During intense exercise, muscles shift to anaerobic respiration when oxygen is insufficient. This produces lactic acid from pyruvate. The accumulation of lactic acid in muscle tissue lowers the local pH, causing the sensation of tiredness and pain known as muscle fatigue. Concept Tested: Lactic acid accumulation causing muscle fatigue during anaerobic respiration

★ JOVIK Exam Insight The lactic acid–muscle fatigue link is a high-frequency NDA concept. It has been tested in NDA 2009-II, 2015-II, and 2025-I in closely related forms. The key point: lactic acid is produced from pyruvate, not directly from glucose.

Q. 44. Which one of the following is not an example of eukaryotic organism?

(a) Yeast

(b) Bacteria

(c) Plant

(d) Human being

Answer: (b) Bacteria

Explanation: Bacteria are prokaryotic organisms. They lack a membrane-bound nucleus and membrane-bound organelles. Yeast is a fungus and is eukaryotic. Plants and human beings are eukaryotes with complex cell structures including a true nucleus. Concept Tested: Prokaryote vs. eukaryote: bacteria as prokaryotes

NDA 2015-I

Q. 45. Energy is required for maintenance of life. It is obtained by a process called

(a) Metabolism

(b) Phagocytosis

(c) Photorespiration

(d) Decomposition

Answer: (a) Metabolism

Explanation: Metabolism refers to all the chemical reactions that occur in a living organism to maintain life. It includes both catabolism (breakdown of molecules to release energy) and anabolism (building up of molecules using energy). Respiration, which is part of metabolism, is the direct source of energy (ATP) for cells. Concept Tested: Metabolism as the process by which living organisms obtain and use energy

Q. 46. Which one of the following is the smallest unit showing the properties of life such as capacity for metabolism, response to the environment, growth and reproduction?

(a) Gene

(b) Chromosome

(c) Nucleus

(d) Cell

Answer: (d) Cell

Explanation: The cell is the smallest unit of life that shows all properties of living organisms: metabolism, growth, reproduction, and response to the environment. Genes and chromosomes are components inside the cell. The nucleus is an organelle within the cell and cannot independently perform all life functions. Concept Tested: Cell as the basic structural and functional unit of life

NDA 2014-II

Q. 47. Statement I: Amoeba is a unicellular organism and the single cell performs all functions of a living organism.

Statement II: Cell is the fundamental unit of living organism.

(a) Both the statements are individually true and Statement II is the correct explanation of Statement I

(b) Both the statements are individually true but Statement II is not the correct explanation of Statement I

(c) Statement I is true but Statement II is false

(d) Statement I is false but Statement II is true

Answer: (a) Both the statements are individually true and Statement II is the correct explanation of Statement I

Explanation: Statement I is correct: Amoeba is unicellular and its single cell carries out all life functions. Statement II is also correct: the cell is the fundamental structural and functional unit of life. Statement II explains why Statement I is true: because the cell is the fundamental unit, a single cell in Amoeba is sufficient to perform all life functions. Concept Tested: Cell as the fundamental unit of life; Amoeba as an example of a unicellular organism

Q. 48. Growth and repair of damaged tissue involve

(a) mitotic cell division only

(b) both mitotic and meiotic cell divisions

(c) meiotic cell division only

(d) amitotic cell division only

Answer: (a) mitotic cell division only

Explanation: Mitosis produces two genetically identical daughter cells. It is the type of cell division used for growth, repair, and replacement of cells in the body. Meiosis is used only for the production of reproductive cells (gametes). Growth and tissue repair do not involve meiosis. Concept Tested: Mitosis: the type of cell division responsible for growth and tissue repair

Q. 49. Which one of the following cell organelles is absent in animal cell?

(a) Cell membrane

(b) Endoplasmic reticulum

(c) Cell wall

(d) Mitochondria

Answer: (c) Cell wall

Explanation: Animal cells do not have a cell wall. They have only the cell membrane (plasma membrane) as the outer boundary. Plant cells have both a cell membrane and a cell wall. Cell wall provides rigidity and structural support, which plant cells require but animal cells do not. Concept Tested: Cell wall: present in plant cells, absent in animal cells

NDA 2014-I

Q. 50. Within an animal cell, the most abundant inorganic constituent of protoplasm is

(a) sodium and potassium salt

(b) water

(c) iron

(d) phosphate

Answer: (b) water

Explanation: Water is the most abundant inorganic constituent of protoplasm in animal cells. It typically constitutes 70–90% of the cell’s mass. Water acts as a solvent, medium for metabolic reactions, and helps maintain cell shape. Sodium, potassium, iron, and phosphate are present in much smaller quantities. Concept Tested: Water as the most abundant inorganic constituent of protoplasm

Q. 51. The site of cellular respiration in animal cell is

(a) ribosome

(b) mitochondria

(c) endoplasmic reticulum

(d) lysosome

Answer: (b) mitochondria

Explanation: Mitochondria are the sites of cellular respiration. The Krebs cycle occurs in the mitochondrial matrix, and the electron transport chain operates on the inner mitochondrial membrane. ATP is produced in large quantities through this process. Mitochondria are therefore called the “powerhouse of the cell.” Concept Tested: Mitochondria as the site of cellular respiration and ATP production

NDA 2013-I

Q. 52. Consider the following statements regarding osmosis in animal cells:

1. If the water potential of the solution surrounding the cell is too high, the cell shrinks.

2. If the water potential of the solution surrounding the cell is too low, the cell swells and bursts.

3. It is important to maintain a constant water potential inside the animal body.

4. In animal cells, water potential far exceeds the solute potential.

Which of the statements given above is/are correct?

(a) 1 and 2

(b) 3 only

(c) 4

(d) 2 and 3

Answer: (b) 3 only

Explanation: Statement 1 is incorrect: high water potential outside means a dilute (hypotonic) solution. Water enters the cell, causing it to swell, not shrink. Statement 2 is incorrect: low water potential outside is hypertonic: water leaves the cell, causing it to shrink (crenation), not swell. Statement 3 is correct: maintaining water potential homeostasis is essential for normal cell function. Statement 4 is incorrect: in cells at equilibrium, water potential and solute potential are balanced, not one far exceeding the other. Concept Tested: Osmosis in animal cells: correct interpretation of hypertonic and hypotonic solutions

NDA 2012-II

Q. 53. Statement I: Red blood cells burst when placed in water.

Statement II: Due to the phenomenon of osmosis water enters into red blood cells.

(a) Both the statements are individually true and statement II is the correct explanation of statement I

(b) Both the statements are individually true but statement II is not the correct explanation of statement I

(c) Statement I is true but statement II is false

(d) Statement I is false but statement II is true

Answer: (a) Both the statements are individually true and statement II is the correct explanation of statement I

Explanation: Pure water has a higher water potential than the cell contents. By osmosis, water enters the RBC through the selectively permeable membrane. The cell swells and eventually bursts (haemolysis) because animal cells, unlike plant cells, have no rigid cell wall to withstand the pressure. Statement II correctly explains Statement I. Concept Tested: Haemolysis of RBCs in hypotonic solution explained by osmosis

NDA 2012-I

Q. 54. Cell membrane is selectively permeable because

(a) it is made up of selected organic molecules

(b) it does not allow transport of some substances from region of higher concentration to the region of lower concentration

(c) the movement of organic molecules occurs only at specific concentration

(d) it allows the movement of certain molecules in and out of the cell while the movement of other molecules is prevented

Answer: (d) it allows the movement of certain molecules in and out of the cell while the movement of other molecules is prevented

Explanation: Selective permeability means the membrane allows some substances to pass through while blocking others. Small non-polar molecules (like O₂ and CO₂) pass freely. Large or charged molecules (like glucose and ions) require transport proteins. This selective control of entry and exit makes the membrane selectively permeable. Concept Tested: Selective permeability of the cell membrane: allows some molecules, blocks others

NDA 2011-II

Q. 55. Which one among the following cell organelles is semi-permeable?

(a) Cell membrane

(b) Plasma membrane

(c) Cell wall

(d) Nucleus

Answer: (b) Plasma membrane

Explanation: The plasma membrane (cell membrane) is selectively permeable (also called semi-permeable). It controls which substances enter and leave the cell. Cell wall is fully permeable: it allows most substances to pass through freely. The nucleus has its own nuclear envelope with pores that regulate the passage of molecules. Concept Tested: Plasma membrane as a semi-permeable (selectively permeable) structure

NDA 2011-I

Q. 56. Which one among the following statements regarding cell is not correct?

(a) Shape and size of cells are related to specific function

(b) Some cells have changing shapes

(c) Each cell has its own capacity to perform

(d) Same type of cells are present in all body tissues

Answer: (d) Same type of cells are present in all body tissues

Explanation: Different tissues contain different types of cells specialised for specific functions. For example, muscle cells are different from nerve cells or blood cells. Option (d) is incorrect: the same type of cells are NOT present in all body tissues. Each tissue has its own specialised cell type. Concept Tested: Cell specialisation: different tissues have different cell types

Q. 57. Statement I: Oxidation in our body cell releases dangerous free radicals.

Statement II: Our body itself produces anti-oxidants to neutralize harmful free radicals.

(a) Both the statements are individually true and statement II is the correct explanation of statement I

(b) Both the statements are individually true but statement II is not the correct explanation of statement I

(c) Statement I is true but Statement II is false

(d) Statement I is false but statement II is true

Answer: (b) Both the statements are individually true but statement II is not the correct explanation of statement I

Explanation: Both statements are correct. Cellular oxidation (especially in mitochondria during respiration) produces reactive oxygen species (free radicals) that can damage cells. The body produces antioxidants such as catalase, superoxide dismutase, and glutathione peroxidase to neutralise these. However, Statement II is not the correct explanation of Statement I: it is a separate but related fact about the body’s defence mechanism. Concept Tested: Free radicals produced by oxidation; body’s antioxidant defence system

NDA 2010-II

Q. 58. When dried raisins are put in plain water, they swell up. If put again in brine solution, they shrivel up. This phenomenon indicates the property of:

(a) Diffusion

(b) Perfusion

(c) Osmosis

(d) Fusion

Answer: (c) Osmosis

Explanation: Raisins placed in plain water gain water by osmosis: water moves from the dilute solution (water) into the concentrated cell contents through the semi-permeable skin. In brine (salt solution), the outside is more concentrated, so water leaves the raisins by osmosis and they shrivel. This reversible swelling and shrinking is a classic demonstration of osmosis. Concept Tested: Osmosis demonstrated by swelling and shrivelling of raisins in water and brine

NDA 2009-II

Q. 59. Release of which one of the following chemicals is responsible for causing fatigue after muscular activity in human beings?

(a) Glucuronic acid

(b) Uric acid

(c) Pyruvic acid

(d) Lactic acid

Answer: (d) Lactic acid

Explanation: During strenuous muscular activity, insufficient oxygen reaches the muscles. Anaerobic respiration takes over. Pyruvate is converted to lactic acid instead of entering the Krebs cycle. Accumulation of lactic acid in the muscles lowers pH, causing the burning sensation and fatigue associated with intense exercise. Concept Tested: Lactic acid as the cause of muscle fatigue during anaerobic respiration

NDA 2009-I

Q. 60. Which of the following organelles of a cell is/are involved in photosynthesis?

(a) Chloroplast

(b) Mitochondrion

(c) Endoplasmic reticulum

(d) Golgi bodies

Answer: (a) Chloroplast

Explanation: Chloroplasts are the organelles responsible for photosynthesis. They contain chlorophyll, the green pigment that captures light energy. The light-dependent reactions occur in the thylakoid membranes, and the light-independent reactions (Calvin cycle) occur in the stroma of the chloroplast. Concept Tested: Chloroplast as the organelle of photosynthesis

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