NEET 20 Advanced Questions and Answers
(BY BRAJESH KATARA)
1. Biology: How do ribosomes facilitate protein synthesis?
Answer: Ribosomes serve as the molecular machines that decode mRNA and link amino
acids into a polypeptide chain. The smaller subunit reads the mRNA codons while the
larger subunit catalyzes peptide bond formation. Transfer RNAs deliver amino acids, and
the ribosome moves along the mRNA until a complete protein is assembled.
2. Biology: What ensures one-way blood flow in the human heart?
Answer: Four valves – tricuspid, mitral, pulmonary, and aortic – maintain unidirectional
flow. These valves open when pressure builds in one chamber and close to prevent
backflow, synchronizing with the heart’s pumping cycles.
3. Biology: Why is the nephron considered the functional unit of the
kidney?
Answer: Each nephron filters blood through the glomerulus, selectively reabsorbs water
and nutrients, and secretes wastes into the tubule. This multi-step process regulates blood
composition and produces urine.
4. Biology: Describe the molecular events during muscle contraction.
Answer: Calcium ions released from the sarcoplasmic reticulum bind to troponin, shifting
tropomyosin and exposing actin sites. Myosin heads attach, pull actin filaments inward
using ATP, and detach in a cycle, shortening the muscle fiber.
5. Biology: How do enzymes increase reaction speed?
Answer: Enzymes form temporary enzyme–substrate complexes, lowering activation
energy. They bring reactants close together and stabilize intermediate states, enabling
biochemical reactions to proceed rapidly at body temperature.
6. Biology: Why are photosystem I and II essential in photosynthesis?
Answer: Photosystem II captures light energy to split water molecules, releasing electrons
and oxygen. Photosystem I receives these electrons and produces NADPH. Together, they
supply ATP and NADPH for the Calvin cycle.
7. Chemistry: Differentiate ionic and covalent bonding.
Answer: Ionic bonds involve complete transfer of electrons, creating charged ions that
attract each other (e.g., NaCl). Covalent bonds involve sharing of electrons between atoms
(e.g., H2O), resulting in stable molecules.
(BY BRAJESH KATARA)
1. Biology: How do ribosomes facilitate protein synthesis?
Answer: Ribosomes serve as the molecular machines that decode mRNA and link amino
acids into a polypeptide chain. The smaller subunit reads the mRNA codons while the
larger subunit catalyzes peptide bond formation. Transfer RNAs deliver amino acids, and
the ribosome moves along the mRNA until a complete protein is assembled.
2. Biology: What ensures one-way blood flow in the human heart?
Answer: Four valves – tricuspid, mitral, pulmonary, and aortic – maintain unidirectional
flow. These valves open when pressure builds in one chamber and close to prevent
backflow, synchronizing with the heart’s pumping cycles.
3. Biology: Why is the nephron considered the functional unit of the
kidney?
Answer: Each nephron filters blood through the glomerulus, selectively reabsorbs water
and nutrients, and secretes wastes into the tubule. This multi-step process regulates blood
composition and produces urine.
4. Biology: Describe the molecular events during muscle contraction.
Answer: Calcium ions released from the sarcoplasmic reticulum bind to troponin, shifting
tropomyosin and exposing actin sites. Myosin heads attach, pull actin filaments inward
using ATP, and detach in a cycle, shortening the muscle fiber.
5. Biology: How do enzymes increase reaction speed?
Answer: Enzymes form temporary enzyme–substrate complexes, lowering activation
energy. They bring reactants close together and stabilize intermediate states, enabling
biochemical reactions to proceed rapidly at body temperature.
6. Biology: Why are photosystem I and II essential in photosynthesis?
Answer: Photosystem II captures light energy to split water molecules, releasing electrons
and oxygen. Photosystem I receives these electrons and produces NADPH. Together, they
supply ATP and NADPH for the Calvin cycle.
7. Chemistry: Differentiate ionic and covalent bonding.
Answer: Ionic bonds involve complete transfer of electrons, creating charged ions that
attract each other (e.g., NaCl). Covalent bonds involve sharing of electrons between atoms
(e.g., H2O), resulting in stable molecules.
