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micro-organisms-and-cell-l2 MCQ - Practice Questions with Answers

Solve 10 micro-organisms-and-cell-l2 questions for RAS/RPSC preparation.

Practice questions

Q1Assertion: Yeast helps dough become soft and fluffy. Reason: Yeast releases carbon dioxide during respiration in warm dough. Choose the correct option.

A Both assertion and reason are true, but the reason does not explain the assertion.
B Assertion is true, but reason is false.
C Both assertion and reason are true, and the reason explains the assertion.
D Assertion is false, but reason is true.
Explanation

Devika can solve this by matching organism, process and result: yeast is a fungus, it respires in warm dough, carbon dioxide bubbles form, and the dough becomes fluffy. The reason is not decorative; it gives the mechanism behind the assertion.

Q2Which set of statements is fully correct about cells and viruses?

A Plant cells lack cell wall; animal cells have chloroplasts; viruses are multicellular.
B Bacteria have a well-defined nucleus; viruses make food by photosynthesis.
C Animal cells have cell wall; fungi have chloroplasts; bacteria are always multicellular.
D Plant cells have cell wall; bacteria lack a well-defined nucleus; viruses are acellular.
Explanation

Karan should compare the noun in each clause with the structure attached to it. Plant cell plus wall is safe, bacteria plus nucleoid or no well-defined nucleus is safe, and virus plus acellular is safe. The other groups mix correct vocabulary with wrong pairings.

Q3Asha is checking the current NCERT anchor for this topic. Which title should she cite for Grade 8 Curiosity?

A Curiosity
B Science, without any current title
C Maths Mela
D Our Wondrous World
Explanation

Asha should cite Curiosity because NCERT's own textbook page and prelims PDF identify the Grade 8 Curiosity textbook by that title for the current cycle. The other options are either stale, wrong subject, or wrong school stage, so they would weaken a REET source note.

Q4Which pair is correctly matched for plant and animal cells?

A Plant cell — cell wall and chloroplast; Animal cell — no cell wall
B Plant cell — no boundary; Animal cell — chloroplast for photosynthesis
C Plant cell — nucleoid only; Animal cell — cell wall and chlorophyll
D Plant cell — acellular; Animal cell — multiplies only inside host cell
Explanation

Karan should use the diagram rule: plant cells have a wall and chloroplasts, while animal cells do not have a cell wall. The wrong options are built by shifting bacterial or viral features into plant and animal cells.

Q5Imran observes pond water under a microscope. Which statement best defines microorganisms at Class 8 level?

A All microorganisms are visible if we look carefully in sunlight.
B They are tiny living forms generally not visible to unaided eyes.
C They are always multicellular animals.
D They are only disease-causing viruses.
Explanation

Imran's observation needs a microscope because microorganisms are too small for unaided eyes. Option B is broad enough to include bacteria, protozoa, fungi and algae. It also avoids the common trap of treating all microbes as viruses or all microbes as harmful.

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More questions

6Match the microbe with the classroom example: 1. Lactobacillus 2. Rhizobium 3. Yeast 4. Fungi and bacteria as decomposers.

A1-curd, 2-legume root nodules, 3-risen dough, 4-manure from plant waste
B1-risen dough, 2-curd, 3-root nodules, 4-microscope lens
C1-virus infection, 2-spoiled fruit only, 3-nitrogen fixation, 4-animal cell wall
D1-plant chloroplast, 2-animal nucleus, 3-bacterial nucleoid, 4-virus cell wall

7A teacher gives four cards: spoiled fruit, curd, dough, and legume roots. Which option names the best microbe-process links?

ASpoiled fruit-vaccine; curd-virus; dough-Rhizobium; roots-yeast
BSpoiled fruit-microbial growth; curd-Lactobacillus; dough-yeast; roots-Rhizobium
CSpoiled fruit-chloroplast; curd-nucleoid; dough-cell wall; roots-animal cell
DSpoiled fruit-clean water only; curd-no microbe; dough-no gas; roots-no bacteria

8Assertion: Rhizobium in legume root nodules can help maintain soil fertility. Reason: These bacteria trap nitrogen from air and make it useful for plants.

AAssertion is true, but reason is false because nitrogen comes only from chemical fertiliser.
BAssertion is false, but reason is true.
CBoth are true, but the reason explains curd formation only.
DBoth are true, and the reason correctly explains the assertion.

9Who first used the word cell in science after observing cork?

AAntonie van Leeuwenhoek
BRobert Hooke
CAnanda Mohan Chakrabarty
DLouis Pasteur

10Meena says, “All bacteria are harmful.” Which response best corrects her?

AAgree, because bacteria are mentioned only under diseases.
BSay bacteria are plants, so they cannot harm humans.
CCompare Lactobacillus in curd, Rhizobium in roots, and disease-causing microbes separately.
DAvoid the question because beneficial microbes are outside REET science.

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