Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R:
Assertion A: ATP is used at two steps in glycolysis.
Reason R: First ATP is used in converting glucose into glucose-6-phosphate and second ATP is used in conversion of fructose-6- phosphate into fructose-1-6-diphosphate.
In the light of the above statements, choose the correct answer from the options given below is true:
The number of substrate level phosphorylations
in one turn of citric acid cycle is:
Explanation:
In one turn of the citric acid cycle, substrate-level phosphorylation occurs once. Succinyl-CoA synthetase converts succinyl-CoA to succinate and produces one GTP (or ATP, depending on the organism). Thus, the number of substrate-level phosphorylations per cycle is one. Options Zero, Two, or Three do not match this NCERT-stated observation.
🧠 Did You Know?
Only one molecule of GTP/ATP is formed per cycle by substrate-level phosphorylation; the rest of the cycle’s energy is captured in NADH and FADH2 during redox reactions.
💡 NCERT Memory Line:
In one turn of the TCA cycle, one substrate-level phosphorylation yields one GTP (ATP) molecule.
Respiratiory Quotient (RQ) value of tripalmitin is:
Explanation:
RQ = CO2 evolved / O2 consumed during respiration. For fats (like tripalmitin, a triglyceride), RQ is about 0.7, as fats yield more energy with less CO2 per O2 consumed. Therefore, the RQ value of tripalmitin is 0.7 (option 3).
🧠 Did You Know?
Carbohydrates have RQ ≈ 1.0, proteins ≈ 0.8, and fats ≈ 0.7. Lipids produce less CO2 per O2 used compared with carbohydrates.
💡 NCERT Memory Line:
RQ of carbohydrates is about 1.0; fats give about 0.7; proteins around 0.8—these values help identify fuel utilization in cellular respiration.
