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Cell & Microorganisms — Homi Bhabha Class 6 Biology MCQs with Solutions
Free Homi Bhabha Class 6 Biology Cell & Microorganisms MCQs with step-by-step solutions covering Structure of a Cell, Plant vs Animal Cells, Useful Microorganisms, Harmful Microorganisms. Practise online on Prepizo — no login needed.
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Sample questions with solutions
Q1 — Structure of a Cell · easy · theory
The scientist who first discovered cells while looking at a thin slice of cork was:
A. Isaac Newton
B. Robert Hooke ✓ Correct
C. Louis Pasteur
D. Charles Darwin
Solution: Robert Hooke saw tiny box-like spaces in cork in 1665 and named them cells.
Q2 — Structure of a Cell · easy · theory
The smallest basic unit that makes up the body of every living thing is the:
A. Brick
B. Atom
C. Cell ✓ Correct
D. Organ
Solution: The cell is the basic building block of all living things.
Q3 — Structure of a Cell · easy · theory
To see a single cell clearly, we need to use a:
A. Telescope
B. Stethoscope
C. Magnet
D. Microscope ✓ Correct
Solution: Cells are far too small to see with the naked eye, so we use a microscope.
Q4 — Structure of a Cell · easy · theory
The part of a cell that controls all its activities, like a captain, is the:
A. Cell wall
B. Cell membrane
C. Nucleus ✓ Correct
D. Cytoplasm
Solution: The nucleus is the control centre of the cell and directs its work.
Q5 — Plant vs Animal Cells · easy · theory
Which part is found in a plant cell but NOT in an animal cell?
A. Cell membrane
B. Cytoplasm
C. Cell wall ✓ Correct
D. Nucleus
Solution: A cell wall is present only in plant cells; animal cells have just a cell membrane.
Q6 — Plant vs Animal Cells · easy · theory
The green colour of plant cells is due to a substance called:
A. Cytoplasm
B. Blood
C. Chlorophyll ✓ Correct
D. Water
Solution: Chlorophyll is the green colouring matter in plant cells that helps make food.
Q7 — Plant vs Animal Cells · easy · theory
Animal cells are usually ___ in shape.
A. triangular
B. star-shaped
C. perfectly square
D. round or irregular ✓ Correct
Solution: Animal cells are generally round or irregular, as they have no rigid cell wall.
Q8 — Plant vs Animal Cells · easy · theory
Which of these is present in BOTH plant and animal cells?
A. Nucleus ✓ Correct
B. Large central vacuole
C. Cell wall
D. Chloroplast
Solution: The nucleus is found in both plant and animal cells.
Q9 — Useful Microorganisms · easy · theory
Very tiny living things that can be seen only through a microscope are called:
A. Minerals
B. Insects
C. Machines
D. Microorganisms ✓ Correct
Solution: Microorganisms are living things too small to be seen with the naked eye.
Q10 — Useful Microorganisms · easy · theory
Which microorganism is used in a bakery to make bread dough rise?
A. Earthworm
B. Yeast ✓ Correct
C. Housefly
D. Spider
Solution: Yeast makes dough rise and gives bread its soft, spongy texture.
Q11 — Useful Microorganisms · easy · theory
Milk is changed into curd (dahi) with the help of:
A. Bacteria ✓ Correct
B. Sand
C. Sugar
D. Salt
Solution: Helpful bacteria turn milk into curd.
Q12 — Useful Microorganisms · easy · theory
Microorganisms that break down dead plants and animals and keep the surroundings clean are called:
A. Decomposers ✓ Correct
B. Hunters
C. Producers
D. Predators
Solution: Decomposers rot away dead matter and clean up the environment.
Q13 — Harmful Microorganisms · easy · theory
Microorganisms that cause diseases are commonly called:
A. Gems
B. Grains
C. Germs ✓ Correct
D. Gums
Solution: Disease-causing microorganisms are commonly known as germs.
Q14 — Harmful Microorganisms · easy · theory
The greenish, fuzzy growth seen on stale bread left for many days is caused by a:
A. fungus (mould) ✓ Correct
B. fish
C. fern
D. frog
Solution: A mould, which is a fungus, grows on stale bread and spoils it.
Q15 — Harmful Microorganisms · easy · theory
Malaria is spread from one person to another by the bite of a:
A. housefly
B. butterfly
C. bee
D. mosquito ✓ Correct
Solution: The malaria germ is carried and spread by mosquito bites.
Q16 — Harmful Microorganisms · easy · theory
Which is a simple way to protect food from spoiling by microorganisms?
A. Keeping it in a refrigerator ✓ Correct
B. Adding extra water to it
C. Leaving it in warm sunlight
D. Keeping it open in the air
Solution: A refrigerator keeps food cold, which stops microorganisms from growing quickly.
Q17 — Structure of a Cell · hard · theory
Which is the longest cell found in the human body?
A. Blood cell
B. Bone cell
C. Skin cell
D. Nerve cell ✓ Correct
Solution: A nerve cell can be very long as it carries messages over long distances in the body.
Q18 — Structure of a Cell · hard · theory
A human being is made of billions of cells, while an Amoeba is made of just one cell. This tells us that:
A. Cells are found only in humans
B. An Amoeba is non-living
C. Both are living things made of cells ✓ Correct
D. Only the human is a living thing
Solution: Every living thing is made of cells, whether it has one cell or billions of them.
Q19 — Plant vs Animal Cells · hard · theory
Why can an animal cell NOT make its own food the way a plant cell can?
A. It has no nucleus
B. It has a cell wall
C. It has no chloroplasts ✓ Correct
D. It has no cytoplasm
Solution: Food-making needs chloroplasts, which animal cells do not have.
Q20 — Plant vs Animal Cells · hard · theory
Which statement correctly compares plant and animal cells?
A. A plant cell has a cell wall and chloroplasts, while an animal cell has neither ✓ Correct
B. An animal cell has a cell wall but a plant cell does not
C. Only animal cells have a nucleus
D. Only plant cells have cytoplasm
Solution: Cell wall and chloroplasts are special to plant cells; animal cells have neither.
Q21 — Useful Microorganisms · hard · theory
Idli and dosa batter turns soft and spongy before cooking because microorganisms cause:
A. melting
B. freezing
C. rusting
D. fermentation ✓ Correct
Solution: Microorganisms ferment the batter, releasing gas that makes it soft and spongy.
Q22 — Useful Microorganisms · hard · theory
Which statement about microorganisms is correct?
A. All microorganisms cause disease
B. Microorganisms are non-living
C. Not all microorganisms are harmful; many are useful to us ✓ Correct
D. Microorganisms can be seen easily with bare eyes
Solution: Many microorganisms are helpful, for example in making curd, bread and medicines.
Q23 — Harmful Microorganisms · hard · theory
Why does food kept in a refrigerator stay fresh longer than food left on the table?
A. Cold makes the food heavier
B. Cold adds nutrients to the food
C. Cold kills all insects
D. Cold slows down the growth of microorganisms ✓ Correct
Solution: Microorganisms grow slowly in the cold, so refrigerated food spoils much later.
Q24 — Harmful Microorganisms · hard · theory
Which set lists ONLY diseases caused by microorganisms?
A. Cholera, malaria and tuberculosis ✓ Correct
B. Hunger, thirst and sleep
C. Blindness from an injury
D. Fracture, sprain and cut
Solution: Cholera, malaria and tuberculosis are all caused by microorganisms; the others are not.
Q25 — Structure of a Cell · medium · theory
The jelly-like material that fills the cell and where many life activities take place is called:
A. Nucleus
B. Cytoplasm ✓ Correct
C. Cell wall
D. Cell membrane
Solution: Cytoplasm is the jelly-like fluid inside a cell where its activities happen.
Q26 — Structure of a Cell · medium · theory
The thin outer covering that surrounds a cell and controls what goes in and out is the:
A. Nucleus
B. Cytoplasm
C. Chloroplast
D. Cell membrane ✓ Correct
Solution: The cell membrane is the outer boundary that decides what enters or leaves the cell.
Q27 — Structure of a Cell · medium · theory
Amoeba is made up of only one cell. An organism made of a single cell is said to be:
A. Multicellular
B. Unicellular ✓ Correct
C. Non-living
D. Colourless
Solution: Uni means one, so an organism made of a single cell, like Amoeba, is unicellular.
Q28 — Structure of a Cell · medium · theory
Which group correctly names three parts found in almost every cell?
A. Cell membrane, cytoplasm and nucleus ✓ Correct
B. Bricks, cement and sand
C. Roots, stem and leaves
D. Brain, heart and lungs
Solution: Nearly every cell has a cell membrane, cytoplasm inside it, and a nucleus.
Q29 — Plant vs Animal Cells · medium · theory
The green structures in plant cells that help the plant make its own food are called:
A. Membranes
B. Vacuoles
C. Chloroplasts ✓ Correct
D. Nuclei
Solution: Chloroplasts contain chlorophyll and carry out food-making in plant cells.
Q30 — Plant vs Animal Cells · medium · theory
Plant cells have a large fluid-filled space called a ___, which is usually very small in animal cells.
A. nucleus
B. membrane
C. chloroplast
D. vacuole ✓ Correct
Solution: A plant cell has a big central vacuole, while animal cells have only small ones.