Prepare for NEET Biology Respiration in Plants with MCQs & PYQs on NEET.GUIDE. Access free practice, previous year questions, and expert explanations of glycolysis, Krebs cycle, and more.
During aerobic respiration, the complete oxidation of one molecule of glucose theoretically yields 38 ATP. However, the actual yield is often lower. Which of the following is NOT a significant contributor to this reduced ATP yield?
Incomplete oxidation of glucose in the cytoplasm
Leakage of protons across the inner mitochondrial membrane
Utilization of the proton gradient for processes other than ATP synthesis
Variations in the efficiency of the electron transport chain
Which specific component of the electron transport chain is directly responsible for the reduction of oxygen to water during aerobic respiration?
NADH dehydrogenase
Succinate dehydrogenase
Cytochrome bc1 complex
Cytochrome c oxidase
If the inner mitochondrial membrane were to become permeable to protons, what would be the MOST immediate consequence on ATP synthesis?
ATP synthesis would increase due to increased proton flow.
ATP synthesis would stop because the proton gradient would dissipate.
ATP synthesis would be unaffected as it relies on substrate-level phosphorylation.
ATP synthesis would decrease, but some ATP would still be produced by glycolysis.
A researcher is studying a novel inhibitor that specifically targets the F0 subunit of ATP synthase. What is the most likely direct effect of this inhibitor on aerobic respiration?
Increased electron transport chain activity
Inhibition of proton flow through the inner mitochondrial membrane
Enhanced ATP production
Stimulation of Krebs cycle activity
Under anaerobic conditions, the regeneration of NAD+ for glycolysis is primarily achieved through:
The electron transport chain
Formation of lactate or ethanol
The Krebs cycle
Oxidative phosphorylation
In the context of aerobic respiration, uncoupling agents like 2,4-dinitrophenol (DNP) disrupt ATP synthesis by:
Inhibiting the electron transport chain
Dissipating the proton gradient across the inner mitochondrial membrane
Blocking the binding of NADH to Complex I
Inhibiting the activity of ATP synthase directly
Which of the following conditions would MOST LIKELY result in an R.Q. value greater than 1 in a mammal?
Prolonged starvation
A diet consisting primarily of proteins
Intense exercise leading to lactic acid accumulation
A diet rich in fats
The Pasteur effect describes the inhibitory effect of oxygen on fermentation. This inhibition is primarily due to:
Direct inhibition of fermentative enzymes by oxygen
Increased activity of the electron transport chain
Feedback inhibition of glycolytic enzymes by ATP and citrate
Depletion of NADH required for fermentation
Under anaerobic conditions, if a cell utilizes glucose exclusively via glycolysis, what would be the net ATP yield per glucose molecule if the glyceraldehyde-3-phosphate dehydrogenase reaction is bypassed by a hypothetical enzyme that directly converts glyceraldehyde-3-phosphate to 3-phosphoglycerate without generating NADH?
0 ATP
2 ATP
4 ATP
6 ATP
Is oxygen required for glycolysis to occur?
Yes
No
Only in the initial steps
Only in the final steps
