Exams › SSC CGL (Prelims) › General › Biology
14 questions with worked solutions.
Q1. What is the primary function of mitochondria?
Answer: Energy production
Mitochondria are the site of cellular respiration and produce ATP, the energy currency of the cell. That is why they are called the powerhouse of the cell.
Q2. The term polygenic inheritance refers to:
Answer: Multiple genes controlling one trait
Polygenic inheritance means a single trait is controlled by multiple genes. Such traits often show continuous variation, like height or skin colour.
Q3. Which macromolecule primarily stores genetic information?
Answer: Nucleic acids
Genetic information is stored in nucleic acids, mainly DNA and RNA. Proteins, lipids, and carbohydrates perform other structural or metabolic roles.
Q4. Which gland in the human body secretes insulin?
Answer: Pancreas
Insulin is secreted by the beta cells of the islets of Langerhans in the pancreas. It helps regulate blood glucose levels.
Q5. Which of the following pairs of nutrient type and nutrient is correctly matched?
Answer: Micronutrient – Molybdenum
Molybdenum is a micronutrient because plants need it in trace amounts. Nitrogen is a macronutrient, while copper and zinc are also micronutrients, so the only correctly matched pair is Micronutrient – Molybdenum.
Answer: 1 and 3 only
Chlorophyll absorbs light energy, which is essential for photosynthesis. Oxygen is released as a by-product during the process. The statement that it occurs only at night is false.
Q7. Which of these is NOT a nucleotide?
Answer: Ribose
Adenine, cytosine, and guanine are nitrogenous bases found in nucleic acids. Ribose is a pentose sugar, not a nucleotide.
Answer: Only 1 and 2 are correct
Photosynthesis generally requires sunlight, and chlorophyll absorbs light energy. It does not occur in mitochondria; it occurs in chloroplasts. Therefore, only statements 1 and 2 are correct.
Answer: Only 1 and 2 are correct
IgM is the first antibody produced in a primary immune response, and IgD is mainly present on B-cell surfaces as a receptor. IgG is not the principal antibody in mucosal secretions; that role is mainly played by IgA.
Answer: Only 1 and 2 are correct
Plasma carries dissolved nutrients, hormones, and other substances, and red blood cells contain haemoglobin. Platelets are involved in clotting, not oxygen transport, so only statements 1 and 2 are correct.
Q11. Which of the following complexes is also called a light-harvesting complex?
Answer: Antenna complex
The antenna complex is also known as the light-harvesting complex because it absorbs light and transfers the energy to the reaction center. It contains pigment molecules that capture photons efficiently.
Q12. Mitochondria are known as the powerhouse of the cell because they produce:
Answer: ATP
Mitochondria produce ATP, which is the primary energy currency of the cell. This is why they are called the powerhouse of the cell.
Q13. The process of nitrification in the nitrogen cycle involves:
Answer: Conversion of ammonia to nitrites and then nitrates
Nitrification is the biological oxidation of ammonia into nitrites and then nitrates by nitrifying bacteria. It is an important step in making nitrogen available to plants.
Q14. Mitochondria are best known for carrying out which of the following roles in a cell?
Answer: Generation of energy
Mitochondria are the site of cellular respiration in eukaryotic cells. They generate ATP, which is the main energy currency of the cell. Therefore, their primary role is generation of energy.