Cell Structure, Organelles and Cell Theory

Attempt the quiz above first, then review every question with its correct answer and a short explanation below.

1. Q1.The powerhouse of the cell is the:

   • A.mitochondrion✓ Correct Answer
   • B.ribosome
   • C.Golgi apparatus
   • D.lysosome

   Explanation: It produces most of the cell's ATP.

2. Q2.The cell was first observed by:

   • A.Anton van Leeuwenhoek
   • B.Robert Brown
   • C.Louis Pasteur
   • D.Robert Hooke✓ Correct Answer

   Explanation: He saw dead cork cells under a microscope in 1665.

3. Q3.The cell theory was proposed by:

   • A.Watson and Crick
   • B.Mendel and Darwin
   • C.Hooke and Brown
   • D.Schleiden and Schwann✓ Correct Answer

   Explanation: They stated that all organisms are made of cells.

4. Q4.Proteins are synthesised on the:

   • A.lysosomes
   • B.vacuoles
   • C.centrioles
   • D.ribosomes✓ Correct Answer

   Explanation: Ribosomes may lie free or on the rough ER.

5. Q5.The plant cell wall is mainly made of:

   • A.cellulose✓ Correct Answer
   • B.chitin
   • C.protein
   • D.lipid

   Explanation: Fungal walls are made of chitin.

6. Q6.The control centre of the cell is the:

   • A.mitochondrion
   • B.vacuole
   • C.plastid
   • D.nucleus✓ Correct Answer

   Explanation: It contains the genetic material.

7. Q7.Photosynthesis takes place in the:

   • A.mitochondria
   • B.chloroplasts✓ Correct Answer
   • C.lysosomes
   • D.ribosomes

   Explanation: They contain the green pigment chlorophyll.

8. Q8.Lysosomes are known as the "suicide bags" of the cell because they:

   • A.produce energy
   • B.store food
   • C.contain enzymes that can digest the cell itself✓ Correct Answer
   • D.make proteins

   Explanation: They release digestive enzymes if the cell is damaged.

9. Q9.The Golgi apparatus is mainly involved in:

   • A.photosynthesis
   • B.packaging and secretion of materials✓ Correct Answer
   • C.respiration
   • D.DNA replication

   Explanation: It modifies and ships proteins in vesicles.

10. Q10.The endoplasmic reticulum studded with ribosomes is called the:

    • A.smooth ER
    • B.Golgi body
    • C.plastid
    • D.rough ER✓ Correct Answer

    Explanation: Smooth ER lacks ribosomes and makes lipids.

11. Q11.Prokaryotic cells lack a:

    • A.cell wall
    • B.ribosome
    • C.membrane-bound nucleus✓ Correct Answer
    • D.genetic material

    Explanation: Bacteria are prokaryotes.

12. Q12.The fluid mosaic model of the plasma membrane was proposed by:

    • A.Singer and Nicolson✓ Correct Answer
    • B.Hooke and Brown
    • C.Watson and Crick
    • D.Mendel and Morgan

    Explanation: It was proposed in 1972.

13. Q13.The smallest known cell is that of:

    • A.Amoeba
    • B.yeast
    • C.Mycoplasma✓ Correct Answer
    • D.Spirogyra

    Explanation: It is a bacterium without a cell wall.

14. Q14.The largest single cell is the:

    • A.egg of an ostrich✓ Correct Answer
    • B.human egg cell
    • C.Amoeba
    • D.a red blood cell

    Explanation: The yolk of the ostrich egg is one cell.

15. Q15.The large central vacuole is a feature of:

    • A.animal cells
    • B.bacteria
    • C.mature plant cells✓ Correct Answer
    • D.red blood cells

    Explanation: It maintains turgor and stores substances.

16. Q16.Besides the nucleus, DNA is also found in:

    • A.lysosomes
    • B.mitochondria✓ Correct Answer
    • C.Golgi body
    • D.ribosomes

    Explanation: Mitochondria and chloroplasts have their own DNA.

17. Q17.The statement "omnis cellula e cellula" is attributed to:

    • A.Rudolf Virchow✓ Correct Answer
    • B.Matthias Schleiden
    • C.Robert Hooke
    • D.Theodor Schwann

    Explanation: It means all cells arise from pre-existing cells.

18. Q18.Centrioles are found in:

    • A.plant cells only
    • B.animal cells and help in cell division✓ Correct Answer
    • C.bacteria only
    • D.red blood cells only

    Explanation: They organise the spindle fibres.

19. Q19.A normal human body cell has how many chromosomes?

    • A.23
    • B.44
    • C.46✓ Correct Answer
    • D.48

    Explanation: They exist as 23 pairs.

20. Q20.Which organelle is responsible for detoxification and lipid synthesis?

    • A.rough endoplasmic reticulum
    • B.smooth endoplasmic reticulum✓ Correct Answer
    • C.centriole
    • D.nucleolus

    Explanation: It is abundant in liver cells.