Q10. Which organelles are involved in protein transport?
[RPSC Senior Teacher Grade II (Science), 1 July 2017]
(a) Endoplasmic reticulum and Golgi bodies
(b) Golgi bodies and mitochondria
(c) Endoplasmic reticulum and mitochondria
(d) Lysosomes, Golgi bodies and nucleolus
Answer: (a) Endoplasmic reticulum and Golgi bodies
Explanation: Proteins destined for secretion commonly enter rough endoplasmic reticulum, then travel in vesicles to the Golgi apparatus. The Golgi modifies, sorts and repackages them for delivery. These structures form major components of the eukaryotic endomembrane trafficking system.
Q9. Peptide synthesis inside a cell usually occurs in:
[UPPSC GIC Lecturer (Botany) Examination 2017]
(a) Mitochondria
(b) Chromoplasts
(c) Ribosomes
(d) Golgi bodies
Answer: (c) Ribosomes
Explanation: Ribosomes join amino acids into polypeptide chains using the codon sequence of messenger RNA. This process is translation. Ribosomes occur freely in cytoplasm or attach to rough ER; mitochondria synthesize some proteins on their own ribosomes too.
Q8. Which cells do not contain a nucleus? 1. Root hair cells 2. Red blood cells 3. Platelets 4. Monocytes
[UPSC CDS (II), General Knowledge, 23 October 2016]
(a) 1 only
(b) 2 and 3 only
(c) 1, 2 and 4
(d) 2, 3 and 4
Answer: (b) 2 and 3 only
Explanation: Mature mammalian red blood cells expel their nuclei, and platelets are anucleate cell fragments involved in clotting. Root hair cells and monocytes possess nuclei. Lack of a nucleus helps mammalian erythrocytes accommodate more haemoglobin but limits their capacity for division.
Q7. The living content of the cell is called protoplasm. It is composed of:
[UPSC CDS (I), General Knowledge, 14 February 2016]
(a) Cytoplasm only
(b) Cytoplasm and nucleoplasm
(c) Nucleoplasm only
(d) Cytoplasm, nucleoplasm and other organelles
Answer: (d) Cytoplasm, nucleoplasm and other organelles
Explanation: Protoplasm is a traditional collective term for a cell’s living contents, including cytoplasm, nucleoplasm and organelles. Cytoplasm excludes the contents of the nucleus, whereas nucleoplasm is inside it. The question tests the broader meaning of protoplasm.
Q6. Which organelle helps in the formation of the sperm acrosome?
[RPSC Senior Teacher Grade II (Science) Examination 2015]
(a) Mitochondria
(b) Golgi complex
(c) Ribosomes
(d) Chloroplast
Answer: (b) Golgi complex
Explanation: The sperm acrosome develops from the Golgi apparatus during sperm formation. It contains enzymes used during penetration of protective layers around the ovum. The Golgi’s role in processing and packaging biological products makes this specialized structure possible.
Q5. Which is the longest cell in animals?
[WBCS Preliminary Examination 2014]
(a) Nerve cell
(b) Hepatocyte
(c) Blood cell
(d) Muscle cell
Answer: (a) Nerve cell
Explanation: A neuron can extend over a considerable distance through its axon, making nerve cells the longest cells in many animals. Certain human motor neurons run from the spinal cord to the feet, carrying electrical signals across long distances.
Q4. Which part of the animal cell is called its powerhouse?
[MPPSC Preliminary Examination 2010]
(a) Cell wall
(b) Nucleus
(c) Mitochondria
(d) Entire cell
Answer: (c) Mitochondria
Explanation: Mitochondria are described as the powerhouse because their inner membranes generate much of the cell’s ATP through oxidative phosphorylation. Glycolysis starts in the cytoplasm, after which aerobic metabolism continues in mitochondria. They also possess their own DNA.
Q3. The plasma membrane is mainly built up of:
[UPPCS Main Examination 2008]
(a) Protein
(b) Lipid
(c) Carbohydrate
(d) Both protein and lipid
Answer: (d) Both protein and lipid
Explanation: Biological membranes consist chiefly of a lipid bilayer containing integral and peripheral proteins. Lipids form the permeability barrier; proteins act as channels, transporters, receptors and enzymes. Carbohydrate chains can occur on the outer surface but are not the primary framework.
Q2. Which of the following becomes zero in a fully turgid plant cell?
[WBCS Preliminary Examination 2003]
(a) Water potential
(b) Wall pressure
(c) Osmotic pressure
(d) All of the above
Answer: (a) Water potential
Explanation: In a fully turgid cell at equilibrium with pure water, the positive pressure potential balances the negative solute potential, making total water potential zero under the usual reference convention. Neither osmotic pressure nor wall pressure is necessarily zero.
Q1. Which one of the following statements is correct?
[UPSC Civil Services Preliminary Examination 2002]
(a) Prions are the smallest free-living cells
(b) Mycoplasma cell walls consist of amino sugars
(c) Viroids consist of single-stranded RNA molecules
(d) Rickettsiae lack cell walls
Answer: (c) Viroids consist of single-stranded RNA molecules
Explanation: Viroids are tiny infectious circular single-stranded RNA molecules, especially associated with plant disease. They lack a protein coat. Prions are infectious proteins rather than living cells; mycoplasmas lack cell walls; and rickettsiae are bacteria that possess a cell envelope.
