Q1. Who formulated the cell theory?
a) Schleiden and Schwann
b) Robert Hooke
c) Rudolf Virchow
d) Matthias Schleiden
Show Answer
Correct Answer: a) Schleiden and Schwann
Explanation: The cell theory, stating that all living organisms are composed of cells and cells are the basic units of life, was formulated by Matthias Schleiden (botanist) and Theodor Schwann (zoologist) in 1839. Rudolf Virchow later added the concept of ‘Omnis cellula e cellula’ – all cells arise from pre-existing cells. Robert Hooke discovered cells but did not formulate the cell theory.
Q2. Which of the following statements is NOT a part of the modern cell theory?
a) All living organisms are composed of cells and cell products.
b) Cells are the basic structural and functional units of life.
c) All cells arise from pre-existing cells.
d) Cells are formed de novo from non-living matter.
Show Answer
Correct Answer: d) Cells are formed de novo from non-living matter.
Explanation: The modern cell theory includes: (1) all living organisms are composed of cells and cell products, (2) cells are the basic structural and functional units of life, and (3) all cells arise from pre-existing cells (Omnis cellula e cellula). The idea of spontaneous generation or ‘de novo’ cell formation from non-living matter was disproven by experiments like Pasteur’s swan neck flask experiment.
Q3. The cell organelle primarily responsible for ATP synthesis is:
a) Golgi apparatus
b) Lysosome
c) Mitochondria
d) Ribosome
Show Answer
Correct Answer: c) Mitochondria
Explanation: Mitochondria are known as the ‘powerhouses of the cell’ because they are the primary sites of cellular respiration. During cellular respiration, they oxidize carbohydrates and fats to release energy in the form of ATP (Adenosine Triphosphate). Golgi apparatus is for packaging and secretion, lysosomes for digestion, and ribosomes for protein synthesis.
Q4. Ribosomes are the sites for:
a) Lipid synthesis
b) Protein synthesis
c) Carbohydrate synthesis
d) Nucleic acid synthesis
Show Answer
Correct Answer: b) Protein synthesis
Explanation: Ribosomes are cellular components responsible for protein synthesis or translation. They read the genetic code from mRNA and assemble amino acids into polypeptide chains, which fold to form proteins. Lipid synthesis occurs mainly in smooth endoplasmic reticulum, carbohydrate synthesis in chloroplasts and cytoplasm, and nucleic acid synthesis in nucleus.
Q5. Which organelle is known as the ‘suicidal bag’ of the cell?
a) Mitochondria
b) Lysosome
c) Golgi apparatus
d) Endoplasmic reticulum
Show Answer
Correct Answer: b) Lysosome
Explanation: Lysosomes are membrane-bound vesicles containing hydrolytic enzymes that can digest various biomolecules. They are called ‘suicidal bags’ because if the cell is damaged or needs to be destroyed, lysosomes can release their enzymes to digest the cellular components (autolysis). Mitochondria are powerhouses, Golgi is for packaging, and ER for synthesis and transport.