Question 1. What is the basic structural and functional unit of life?
(a) Tissue
(b) Organ
(c) Cell
(d) Organ system
Answer: (c) Cell
Explanation: All living organisms are made up of cells, and all basic life activities take place in cells.
Question 2. Which of the following is a unicellular organism?
(a) Human
(b) Fish
(c) Bacteria
(d) Neem tree
Answer: (c) Bacteria
Explanation: Bacteria consist of only one cell, so they are unicellular organisms.
Question 3. Who first observed and named the cell?
(a) Robert Brown
(b) Robert Hooke
(c) Anton van Leeuwenhoek
(d) Rudolf Virchow
Answer: (b) Robert Hooke
Explanation: Robert Hooke observed cork under a microscope in 1665 and named the box-like structures “cells”.
Question 4. Which instrument is used to study cells clearly?
(a) Thermometer
(b) Telescope
(c) Microscope
(d) Barometer
Answer: (c) Microscope
Explanation: Cells are too small to be seen clearly with the naked eye, so microscopes are used to study them.
Question 5. The limit of resolution of the human eye mentioned in the chapter is about
(a) 1 mm
(b) 0.1 mm
(c) 10 mm
(d) 0.01 cm
Answer: (b) 0.1 mm
Explanation: Two points separated by about 0.1 mm can be seen as distinct by the unaided human eye.
Question 6. Which microscope can reveal cell structures at nanometre scale?
(a) Simple microscope
(b) Light microscope
(c) Electron microscope
(d) Hand lens
Answer: (c) Electron microscope
Explanation: Electron microscopes show very fine details of cell structure at very high magnification and resolution.
Question 7. The plasma membrane is also called the
(a) nuclear membrane
(b) cell membrane
(c) cell wall
(d) cytoplasm
Answer: (b) cell membrane
Explanation: Plasma membrane is another name for the cell membrane.
Question 8. The cell membrane is
(a) freely permeable
(b) selectively permeable
(c) completely impermeable
(d) non-living
Answer: (b) selectively permeable
Explanation: It allows some substances to pass through while blocking others.
Question 9. Movement of water through a selectively permeable membrane is called
(a) diffusion
(b) transpiration
(c) osmosis
(d) respiration
Answer: (c) osmosis
Explanation: Osmosis is specifically the movement of water across a selectively permeable membrane.
Question 10. Diffusion is the movement of particles from
(a) lower concentration to higher concentration
(b) higher concentration to lower concentration
(c) one cell to another only
(d) nucleus to cytoplasm only
Answer: (b) higher concentration to lower concentration
Explanation: Diffusion is the net movement of particles down their concentration gradient.
Question 11. A cell placed in a hypertonic solution will generally
(a) swell
(b) burst
(c) shrink
(d) divide
Answer: (c) shrink
Explanation: In a hypertonic solution, water moves out of the cell by osmosis, causing it to shrink.
Question 12. Which structure is present in plant, fungal, and bacterial cells in addition to cell membrane?
(a) Nucleus
(b) Cell wall
(c) Golgi apparatus
(d) Lysosome
Answer: (b) Cell wall
Explanation: These cells have an additional outer covering called the cell wall.
Question 13. The plant cell wall is mainly made up of
(a) protein
(b) lipid
(c) cellulose
(d) starch
Answer: (c) cellulose
Explanation: Cellulose is the main component of the plant cell wall.
Question 14. Which of the following does not have a cell wall?
(a) Plant cell
(b) Bacterial cell
(c) Animal cell
(d) Fungal cell
Answer: (c) Animal cell
Explanation: Animal cells do not have a rigid cell wall, which allows flexibility.
Question 15. The jelly-like substance inside the cell is called
(a) vacuole
(b) cytoplasm
(c) nucleolus
(d) chromosome
Answer: (b) cytoplasm
Explanation: Cytoplasm is the semi-fluid substance in which organelles are present.
Question 16. A cell lacking a well-defined nucleus is called
(a) eukaryotic
(b) multicellular
(c) prokaryotic
(d) differentiated
Answer: (c) prokaryotic
Explanation: Prokaryotic cells do not have a membrane-bound nucleus.
Question 17. Which of the following is a prokaryotic cell?
(a) Plant cell
(b) Animal cell
(c) Bacterial cell
(d) Fungal cell
Answer: (c) Bacterial cell
Explanation: Bacteria are prokaryotic because they lack a true nucleus and membrane-bound organelles.
Question 18. Membrane-bound organelles are present in
(a) eukaryotic cells only
(b) prokaryotic cells only
(c) both prokaryotic and eukaryotic cells
(d) viruses only
Answer: (a) eukaryotic cells only
Explanation: Eukaryotic cells contain membrane-bound organelles, while prokaryotic cells do not.
Question 19. The control centre of the cell is the
(a) ribosome
(b) nucleus
(c) lysosome
(d) vacuole
Answer: (b) nucleus
Explanation: The nucleus controls cell activities and contains genetic material.
Question 20. Functional segments of DNA are called
(a) tissues
(b) genes
(c) cristae
(d) plastids
Answer: (b) genes
Explanation: Genes are the functional units of DNA that carry hereditary information.
Question 21. In a non-dividing cell, DNA is present as
(a) genes
(b) chromosomes
(c) chromatin
(d) plastids
Answer: (c) chromatin
Explanation: In non-dividing cells, DNA is present in thread-like chromatin form.
Question 22. Ribosomes are the sites of
(a) photosynthesis
(b) protein synthesis
(c) lipid digestion
(d) respiration
Answer: (b) protein synthesis
Explanation: Ribosomes make proteins for the cell.
Question 23. Which type of ER has ribosomes attached to it?
(a) SER
(b) Smooth ER
(c) Rough ER
(d) Golgi ER
Answer: (c) Rough ER
Explanation: Rough endoplasmic reticulum has ribosomes on its surface.
Question 24. Smooth endoplasmic reticulum mainly helps in the synthesis of
(a) proteins
(b) starch
(c) lipids
(d) DNA
Answer: (c) lipids
Explanation: SER is involved in the synthesis and storage of fats and some hormones.
Question 25. The Golgi apparatus mainly helps in
(a) producing ATP
(b) packaging and sorting materials
(c) cell division
(d) photosynthesis
Answer: (b) packaging and sorting materials
Explanation: Golgi apparatus modifies, sorts, and packages proteins and lipids into vesicles.
Question 26. Lysosomes are known as the
(a) protein factories
(b) powerhouse of the cell
(c) clean-up system of the cell
(d) control centre of the cell
Answer: (c) clean-up system of the cell
Explanation: Lysosomes digest wastes and damaged cell parts.
Question 27. The powerhouse of the cell is
(a) chloroplast
(b) vacuole
(c) mitochondrion
(d) nucleus
Answer: (c) mitochondrion
Explanation: Mitochondria release energy from food and store it as ATP.
Question 28. Energy currency of the cell is
(a) DNA
(b) ATP
(c) RNA
(d) glucose
Answer: (b) ATP
Explanation: ATP stores and supplies energy for cellular activities.
Question 29. The green pigment responsible for photosynthesis is
(a) haemoglobin
(b) chlorophyll
(c) melanin
(d) carotene
Answer: (b) chlorophyll
Explanation: Chlorophyll present in chloroplasts absorbs sunlight for photosynthesis.
Question 30. Which plastid contains chlorophyll?
(a) Leucoplast
(b) Chromoplast
(c) Chloroplast
(d) Vacuoplast
Answer: (c) Chloroplast
Explanation: Chloroplasts are green plastids containing chlorophyll.
Question 31. Chromoplasts mainly give
(a) energy
(b) rigidity
(c) bright colours to flowers and fruits
(d) genetic information
Answer: (c) bright colours to flowers and fruits
Explanation: Chromoplasts contain coloured pigments such as red, orange, and yellow.
Question 32. Leucoplasts are mainly involved in
(a) respiration
(b) food storage
(c) movement
(d) excretion
Answer: (b) food storage
Explanation: Leucoplasts are colourless plastids that store starch, oils, or proteins.
Question 33. A large central vacuole is usually present in
(a) bacterial cells
(b) animal cells
(c) mature plant cells
(d) viruses
Answer: (c) mature plant cells
Explanation: Mature plant cells usually have one large central vacuole filled with cell sap.
Question 34. Mitosis produces
(a) four daughter cells
(b) two genetically identical daughter cells
(c) gametes only
(d) cells with half chromosome number
Answer: (b) two genetically identical daughter cells
Explanation: Mitosis produces two daughter cells similar to the parent cell.
Question 35. Meiosis produces
(a) two identical cells
(b) one daughter cell
(c) four daughter cells with half chromosome number
(d) tissues only
Answer: (c) four daughter cells with half chromosome number
Explanation: Meiosis is a reduction division that forms gametes.
Question 36. Which type of cell division is important for growth and repair?
(a) Meiosis
(b) Mitosis
(c) Fertilisation
(d) Budding only
Answer: (b) Mitosis
Explanation: Growth and repair in body tissues occur through mitosis.
Question 37. Which type of cell division forms gametes?
(a) Mitosis
(b) Meiosis
(c) Binary fission
(d) Budding
Answer: (b) Meiosis
Explanation: Meiosis produces gametes with half the chromosome number.
Question 38. According to Cell Theory, all cells arise from
(a) non-living matter
(b) tissues
(c) pre-existing cells
(d) proteins
Answer: (c) pre-existing cells
Explanation: Rudolf Virchow stated that new cells come only from already existing cells.
Question 39. The process in which many animal cells stop dividing when they touch neighbouring cells is called
(a) diffusion
(b) osmosis
(c) contact inhibition
(d) fertilisation
Answer: (c) contact inhibition
Explanation: Contact inhibition helps control cell division and prevents overgrowth.
Question 40. Uncontrolled cell division can lead to the formation of
(a) plastids
(b) tumours
(c) vacuoles
(d) tissues
Answer: (b) tumours
Explanation: When normal control over cell division is lost, tumours may form.