Multiple Choice Questions (MCQs)
Instruction: Select the correct option for each question.
Who first used the term “cell” after observing thin slices of cork?
a) Antonie van Leeuwenhoek
b) Robert Hooke
c) Louis Pasteur
d) Ananda Mohan Chakrabarty
Answer: b) Robert Hooke
In 1665, Robert Hooke observed cork under a microscope and named the tiny compartments “cells.”- Which tool allows us to view objects too small to be seen with the naked eye?
a) Telescope
b) Periscope
c) Microscope
d) Binoculars
Answer: c) Microscope
Microscopes magnify tiny objects, revealing details invisible to unaided eyes. - A round-bottom flask filled with water can act as:
a) A lens/magnifier
b) A telescope
c) A prism
d) A mirror
Answer: a) A lens/magnifier
The curved water-filled flask bends light like a lens, making objects appear larger. 
Which cell structure is present in plant cells but absent in animal cells?
a) Nucleus
b) Cell membrane
c) Cell wall
d) Cytoplasm
Answer: c) Cell wall
Plant cells have a rigid cell wall; animal cells do not.- Which statement is true about cheek cells?
a) They are rectangular and have a cell wall.
b) They have a large central vacuole.
c) They contain chloroplasts.
d) They are polygon-shaped and lack a cell wall.
Answer: d) They are polygon-shaped and lack a cell wall.
Cheek cells are animal cells—irregular, flat, with no cell wall. - Which part of the cell controls all activities like growth and division?
a) Cytoplasm
b) Nucleus
c) Cell membrane
d) Vacuole
Answer: b) Nucleus
Explanation: The nucleus acts as the control center of the cell. - Spirulina is best described as:
a) A microalga used as a superfood
b) A nitrogen-fixing bacterium
c) A fungus used in bread making
d) A protozoan that causes disease
Answer: a) A microalga used as a superfood
Spirulina is rich in protein and vitamin B12 and is farmed as a dietary supplement. - Which microorganism helps convert milk into curd?
a) Yeast
b) Rhizobium
c) Lactobacillus
d) Amoeba
Answer: c) Lactobacillus
Lactobacillus converts lactose into lactic acid, forming curd.
Fill in the BlanksInstruction: Fill in the blanks with the correct word based on the chapter.
- The jelly-like substance inside a cell where life processes occur is the ______.
Answer: cytoplasm
Cytoplasm contains nutrients and is the site of many cell activities. - The thin, flexible boundary of a cell that controls entry and exit is the ______ ______.
Answer: cell membrane
The cell membrane is porous and selectively allows substances in and out. - In onion peel cells, staining with ______ helps make the cells visible.
Answer: safranin
Red safranin stain highlights cell parts under a microscope. 
Cheek cells are commonly stained with ______ ______.
Answer: methylene blue
Methylene blue makes the nucleus and cell boundaries more visible.
Cheek Cells- The bacteria that fix nitrogen in legume root nodules are called ______.
Answer: Rhizobium
Rhizobium converts atmospheric nitrogen into usable forms for plants. - The process by which yeast makes dough rise by releasing carbon dioxide is called ______.
Answer: fermentation
Yeast ferments sugars to produce CO2, making dough fluffy. - Bacterial genetic material without a nuclear membrane is found in a region called the ______.
Answer: nucleoid
Bacteria lack a well-defined nucleus; DNA lies in the nucleoid region.
Very Short Answer Questions
Instruction: Answer the following questions in one line.
- Who is known as the Father of Microbiology?
Answer: Antonie van Leeuwenhoek. - What do chloroplasts contain that enables photosynthesis?
Answer: Chlorophyll. 
Name the large storage cavity commonly found in plant cells.
Answer: Vacuole.- What shape are muscle cells typically described as?
Answer: Spindle-shaped (tapered at both ends). - Which organisms decompose waste to form manure?
Answer: Bacteria and fungi (microbes).
Short Answer QuestionsInstruction: Answer the following questions in 2–3 lines.
- Why are some microorganisms invisible to the naked eye?
Answer: They are extremely small—often single-celled—and fall below the resolution limit of human vision. Microscopes are needed to magnify them for observation. - How does high salt or sugar preserve pickles and murabbas?
Answer: High salt/sugar creates conditions that draw water out of microbial cells (osmotic effect), preventing their growth and spoilage. 
How do nerve cells (neurons) suit their function?
Answer: Neurons are long and branched, allowing rapid transmission of messages over distances in the body.- Why is warm milk preferred for curd formation?
Answer: Warm conditions help Lactobacillus multiply and convert lactose into lactic acid faster, thickening the milk. - What role do microalgae play in Earth’s oxygen supply?
Answer: Microalgae perform photosynthesis and release a major share of Earth’s oxygen, supporting life and aquatic food chains.
Match the Following
Instruction: Match Column A with the correct option in Column B.
Correct Matches:
- Yeast — b) Fermentation and rising of dough
Explanation: Yeast ferments sugars, releasing CO2 that makes dough rise. - Robert Hooke — e) Coined the term “cell”
Explanation: He named the cork compartments “cells” after observing them. - Rhizobium — c) Nitrogen fixation in legume roots
Explanation: Rhizobium in root nodules converts atmospheric nitrogen into plant-usable forms. - Methane — d) Main component of biogas
Explanation: Anaerobic microbial action produces methane, a fuel. - Chloroplast — a) Photosynthesis in plant cells
Explanation: Chloroplasts contain chlorophyll and perform photosynthesis.