Cell Structure

Cell Structure MDCAT MCQs with answers

44 past paper MCQs on Cell Structure, from the Cell Structure and Function unit of MDCAT Biology. The year each question appeared is shown where known; tap “Show answer” for the correct option and a short solution.

Read the notes first Practise the unit as a quiz

1.The movement of molecules against a concentration gradient is: (MDCAT 2022)

  1. passive transport
  2. active transport
  3. facilitated diffusion
  4. filtration
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Correct answer: (b) active transport

Going uphill against the gradient needs a pump and ATP, which is active transport.

2.Cells of different types can be distinguished on the basis of surface: (MDCAT 2023)

  1. phospholipids
  2. globular proteins
  3. glycolipids and glycoproteins
  4. cholesterol
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Correct answer: (c) glycolipids and glycoproteins

The sugar chains on the outer face of the membrane differ from one cell type to another and act as its markers.

3.A student observed a boundary In both plant and animal cells that controls entry and exit of substances. Which of the following structures is likely being observed? (UHS MDCAT 2025)

  1. Mitochondria
  2. Golgi apparatus
  3. Plasma membrane
  4. Cell wall
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Correct answer: (c) Plasma membrane

The plasma membrane bounds every cell and decides what passes in and out.

4.How are the phospholipid molecules arranged in the plasma membrane? (KMU MDCAT 2025)

  1. Hydrophilic heads face inwards and hydrophobic tails face outwards
  2. Both Hydrophilic heads face each other in the membrane
  3. Hydrophilic heads face outwards and hydrophobic tails face inwards
  4. Hydrophilic heads and hydrophobic tails are randomly distributed
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Correct answer: (c) Hydrophilic heads face outwards and hydrophobic tails face inwards

The bilayer turns its water-loving heads out to the watery surroundings and its tails in.

5.Fluidity of biological membranes is maintained by: (NUMS MDCAT 2025)

  1. Glycoprotein
  2. Saturated fatty acid
  3. Fatty acids
  4. Phospholipids
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Correct answer: (d) Phospholipids

The phospholipid bilayer itself is fluid, its molecules free to move sideways.

6.Under a microscope plant cells appeared rigid in shape, unlike flexible animal cells. Which structure explain this difference? (SIBA MDCAT 2025)

  1. Cell wall
  2. Vacuole
  3. Cytoskeleton
  4. Plasma membrane
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Correct answer: (a) Cell wall

The cellulose cell wall outside the membrane holds the plant cell in shape.

7.Plasma membrane is differentially permeable membrane due to the presence of? (KMU MDCAT 2024)

  1. Carbohydrates
  2. Lipids
  3. Proteins
  4. Vitamins
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Correct answer: (b) Lipids

The lipid bilayer lets small non-polar molecules through and holds ions and polar molecules back.

8.Which function cannot be attributed to plasma membrane lipids? (NUMS MDCAT 2024)

  1. Recognition of cells having non-self surface markers
  2. Maintaining cell membrane flexibility
  3. Control of metabolic reaction across cell membrane
  4. Binding ligands for intracellular response
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Correct answer: (c) Control of metabolic reaction across cell membrane

Lipids make the bilayer and keep it fluid; controlling what crosses it is the work of the proteins.

9.Which one is the function of plasma membrane proteins? (NUMS MDCAT 2024)

  1. Restrict entry of polar molecules
  2. Prevention of freezing during cold weather
  3. Movement of ions in and out of the cell
  4. Maintenance of membrane flexibility
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Correct answer: (c) Movement of ions in and out of the cell

Channel and carrier proteins are what let ions cross the lipid bilayer.

10.Movement of molecules against the concentration gradient is? (UHS MDCAT 2023)

  1. Passive transport
  2. Active transport
  3. Facilitated diffusion
  4. Filtration
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Correct answer: (b) Active transport

Moving a substance against its gradient costs energy, which is what active transport means.

11.Which molecules do not contribute to the formation of biological membranes? (SZABMU MDCAT 2023)

  1. Glycoproteins
  2. Glycolipids
  3. Phospholipids
  4. Nucleoproteins
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Correct answer: (d) Nucleoproteins

Membranes are built of phospholipids with glycolipids and glycoproteins in them; nucleoproteins belong to the chromosomes.

12.Adenylate cyclase, in the cell membrane acts as: (SZABMU MDCAT 2023)

  1. Channel protein
  2. Carrier protein
  3. Enzyme
  4. Receptor
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Correct answer: (c) Enzyme

Adenylate cyclase makes cyclic AMP, so it is an enzyme built into the membrane.

13.Glycogen, lipid droplets form the most important_________of the cell. (SZABMU MDCAT 2023)

  1. Cell organelles
  2. Cell inclusions
  3. Cytoplasmic matrix
  4. Non membranous organelles
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Correct answer: (b) Cell inclusions

Stored granules and droplets, with no membrane of their own, are the cell inclusions.

14.According to the fluid mosaic model of cell membrane, which zone is embedded inside? (NUMS MDCAT 2023)

  1. Hydrophobic
  2. Hydrophilic
  3. Globular
  4. Filamentous
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Correct answer: (a) Hydrophobic

The fatty tails of the phospholipids turn inwards, away from the water on both sides.

15.Cell membrane also contains _______ place by active and passive transport: (NUMS MDCAT 2023)

  1. Lipids
  2. Corner Proteins
  3. Charged pores
  4. Carbohydrates
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Correct answer: (c) Charged pores

Charged pores through the protein channels let ions cross the bilayer.

16.Biologically, plays key roles in maintaining the integrity of lipid bilayer membranes. (UHS MDCAT 2023)

  1. Hydrophilic exclusion
  2. Hydrophobic
  3. Specific heat capacity exclusion
  4. Heat of vaporization
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Correct answer: (b) Hydrophobic

The fatty tails are hydrophobic and turn away from water, which is what holds the bilayer together.

17.What is incorrect about plasma membranes? (PMC MDCAT 2022)

  1. They are involved in maintaining gradients between different compartments
  2. They are involved In cell communication
  3. They are Involved in the exchange of materials
  4. They initiate nuclear division
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Correct answer: (d) They initiate nuclear division

Nuclear division is begun by the centrosome and the spindle, not by the plasma membrane.

18.The movement of water molecules from a region of higher water potential to a region of lower water potential through a semi-permeable membrane is referred to: (PMC MDCAT 2022)

  1. Active transport
  2. Osmosis
  3. Diffusion
  4. Photosynthesis
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Correct answer: (b) Osmosis

Water moving down its potential gradient through a selectively permeable membrane is osmosis.

19.What is the difference between facilitated transport and passive transport? (PMC MDCAT 2022)

  1. All facilitated transport is passive
  2. All passive transport is facilitated
  3. Facilitated transport requires membrane proteins
  4. Passive transport is downhill whereas facilitated transport Is uphill
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Correct answer: (c) Facilitated transport requires membrane proteins

Both run downhill, but facilitated diffusion needs a channel or carrier protein to get through.

20.The protoplast of a plant cell does not include: (PMC MDCAT 2022)

  1. Cell wall
  2. Cell membrane
  3. Vacuoles
  4. Nucleus
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Correct answer: (a) Cell wall

The protoplast is everything inside the wall; the wall itself is outside it.

21.Carbon dioxide passes through the plasma membrane of cells by: (PMC MDCAT 2022)

  1. Active transport
  2. Phagocytosis
  3. Facilitated diffusion
  4. Simple diffusion
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Correct answer: (d) Simple diffusion

Carbon dioxide is small and non-polar, so it passes straight through the bilayer.

22.Glycoproteins and glycolipids are present: (PMC MDCAT 2022)

  1. Within lipid bilayer of plasma membrane
  2. On the outer surface of the lipid bilayer of the plasma membrane
  3. On the inner surface of the lipid bilayer of the plasma membrane
  4. As the bilayer in plasma membrane
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Correct answer: (b) On the outer surface of the lipid bilayer of the plasma membrane

Their sugar chains stand out into the surroundings, on the outer face of the membrane.

23.Which interactions are responsible for the formation of lipid bilayer In the watery environment of the body? (PMC MDCAT 2022)

  1. Hydrophobic interactions between fatty acid tails
  2. Hydrophobic Interactions between phosphate heads
  3. Hydrophilic Interactions between fatty acid tails
  4. Hydrogen bonding between fatty acid tails
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Correct answer: (a) Hydrophobic interactions between fatty acid tails

The fatty tails are driven together away from the water, and that is what holds the bilayer.

24.Which of the following is responsible for giving finnesse and box-like shape to plant cells? (PMC MDCAT 2022)

  1. Cell wall
  2. Cell wall and vacuole
  3. Nucleus and vacuole
  4. Cell membrane
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Correct answer: (a) Cell wall

The rigid cellulose wall holds the plant cell in its box-like shape.

25.Which one of the following can easily pass through plasma membrane (PMC MDCAT 2022)

  1. Fat soluble substances
  2. Protiens
  3. Highly charged materials
  4. polysacchrides
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Correct answer: (a) Fat soluble substances

A fat soluble molecule dissolves in the lipid bilayer and passes straight through.

26.Which of the following is correct for the cell wall: (NUMS MDCAT 2022)

  1. Semi-permeable
  2. Differentially permeable
  3. Permeable
  4. Not permeable
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Correct answer: (c) Permeable

The cellulose wall is fully permeable; it is the membrane inside it that selects.

27.Cell membrane also contain through which movement of materials take place by active and passive transport: (NUMS MDCAT 2022)

  1. Lipid
  2. Corner
  3. Charge pores
  4. Carbohydrates
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Correct answer: (c) Charge pores

Charged pores through the protein channels let ions cross the bilayer.

28.The part of plasma membrane controls the fluidity of the membrane: (NUMS MDCAT 2022)

  1. Glycoprotein
  2. Carrier protein
  3. Lipid
  4. Carbohydrates
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Correct answer: (c) Lipid

The lipid bilayer is what is fluid, and cholesterol among it sets how fluid.

29.The term ‘cell’ was given by (PMC Practice 2021)

  1. Leeuwenhoek
  2. Robert Hooke
  3. Flemming
  4. Robert Brown
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Correct answer: (b) Robert Hooke

Robert Hooke saw the empty boxes of cork and called them cells.

30.Which property of water helps to maintain the integrity of lipid-containing membranes? (PMC MDCAT 2020)

  1. Specific Heat Capacity
  2. Hydrogen Bonding
  3. Cohesion and Adhesion
  4. Hydrophobic exclusion
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Correct answer: (d) Hydrophobic exclusion

The fatty tails are driven together away from water, and that is what holds the bilayer.

31.In which type of cells, cell wall is not present? (PMC MDCAT 2020)

  1. Plant cells
  2. Fungal cells
  3. Bacterial cells
  4. Liver cells
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Correct answer: (d) Liver cells

Animal cells have only a plasma membrane; plants, fungi and bacteria all have walls.

32.Tissue is a (PMC MDCAT 2020)

  1. group of cells
  2. group of organs
  3. group of tissues
  4. group of organisms
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Correct answer: (a) group of cells

A tissue is a group of similar cells doing the same work.

33.If 15 um size object is observed under light microscope, using 5X eyepiece and 10X objective, its magnified image size will be: (UHS MDCAT 2019)

  1. 750 um
  2. 50 um
  3. 500 um
  4. 250 um
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Correct answer: (a) 750 um

The magnification is $5\times10=50$, and $15\times50$ is $750\,\mu\mathrm{m}$.

34.Passive processes for the movement of molecules across cell surface membrane are: (UHS MDCAT 2019)

  1. osmosis and phagocytosis
  2. pinocytosis and facilitated diffusion
  3. facilitated diffusion and osmosis
  4. diffusion and exocytosis
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Correct answer: (c) facilitated diffusion and osmosis

Osmosis and facilitated diffusion both run down the gradient and cost no energy.

35.The ability to distinguish between two separate points/objects is: (UHS MDCAT 2018)

  1. Magnification
  2. Fractionation
  3. Centrifugation
  4. Resolution
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Correct answer: (d) Resolution

Resolution is the power to show two close points as separate.

36.Engulfing of solid particle is termed as: (UHS MDCAT 2017)

  1. Engulfing
  2. Pinocytosis
  3. Phagocytosis
  4. None of the given options
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Correct answer: (c) Phagocytosis

Taking in a solid particle by engulfing it is phagocytosis.

37.What is the percentage of lipids in the chemical composition of plasma membrane? (UHS MDCAT 2017)

  1. 60-80%
  2. 20-40%
  3. 40-80%
  4. 20-60%
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Correct answer: (b) 20-40%

Lipids make up about a fifth to two fifths of the mass of a plasma membrane.

38.Which one is correctly matched with the tail of a phospholipid: (UHS MDCAT 2017)

  1. Hydrophilic
  2. Hydrophobic
  3. Light absorbing
  4. Porphyrin ring
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Correct answer: (b) Hydrophobic

The fatty acid tails are hydrophobic and turn away from the water.

39.The rapid exchange of materials through carrier proteins across the plasma membrane is called: (UHS MDCAT 2016)

  1. Passive Diffusion
  2. Active Transport
  3. Endocytosis
  4. Facilitated Diffusion
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Correct answer: (d) Facilitated Diffusion

A carrier protein passes the molecule down its gradient without cost, which is facilitated diffusion.

40.The basic structure of plasma membrane is provided by: (UHS MDCAT 2016)

  1. Proteins
  2. Cholesterols
  3. Cytoskeleton
  4. Phospholipids
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Correct answer: (d) Phospholipids

The phospholipid bilayer is the framework into which everything else is set.

41.Out of the given options, choose the one which shows the structures found only in plants (UHS MDCAT 2016)

  1. Vacuole, Chloroplast, Ribosomes
  2. Chloroplast, Microtubules, Peroxisomes
  3. Chloroplast, Cell Wall, Vacuole
  4. Chloroplast, Cell Wall, Mitochondria
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Correct answer: (c) Chloroplast, Cell Wall, Vacuole

A chloroplast, a cellulose wall and a large central vacuole are found in plant cells alone.

42.Presence of large central vacuole is the characteristic of: (UHS MDCAT 2016)

  1. Prokaryotes
  2. Protists
  3. Fungi
  4. Plants
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Correct answer: (d) Plants

A large central vacuole holding cell sap is a mark of the plant cell.

43.Fluid mosaic model of plasma membrane states that protein molecules float in a fluid layer. (UHS MDCAT 2015)

  1. Galactose
  2. Phospholipids
  3. Glucose
  4. Carbohydrate
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Correct answer: (b) Phospholipids

The proteins float in a bilayer of phospholipid, which is what makes the model a fluid mosaic.

44.Blood group antigen contains: (UHS MDCAT 2015)

  1. Glycoproteins
  2. Phospholipids
  3. Glycolipids
  4. Sphingolipids
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Correct answer: (a) Glycoproteins

The A and B antigens are the sugar chains of glycoproteins on the red cell surface.

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