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.
A researcher observes that a plant placed in a sealed chamber shows a net decrease in CO2 levels during the day but a net increase at night. What can be inferred about the metabolic processes occurring?
The plant is only respiring, both day and night.
The plant is only photosynthesizing, both day and night.
Photosynthesis exceeds respiration during the day, while respiration exceeds photosynthesis at night.
Respiration exceeds photosynthesis during the day, while photosynthesis exceeds respiration at night.
If a plant's respiration rate significantly exceeds its photosynthetic rate for a prolonged period, what is the MOST likely consequence?
Increased growth and biomass
Enhanced fruit and seed production
Accumulation of starch in storage organs
Depletion of stored carbohydrates and eventual plant death
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
A patient presents with an abnormally high R.Q. Which of the following metabolic derangements is LEAST likely to be the cause?
Hyperventilation
Metabolic acidosis
Lipogenesis
Increased fatty acid oxidation
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
In a hypothetical scenario, a cell has a mutated form of aldolase that cleaves fructose 1,6-bisphosphate into two molecules of dihydroxyacetone phosphate. How many net ATP molecules would be produced from one molecule of glucose under anaerobic conditions in this cell?
0 ATP
2 ATP
4 ATP
6 ATP
Arsenic poisoning can inhibit several enzymes, including lipoic acid-containing enzymes like pyruvate dehydrogenase. How would arsenic poisoning indirectly affect glycolysis?
Arsenic directly inhibits hexokinase, the first enzyme in glycolysis.
Arsenic enhances glycolysis by stimulating phosphofructokinase activity.
By inhibiting pyruvate dehydrogenase, arsenic poisoning would lead to a buildup of pyruvate, which could in turn inhibit glycolysis through feedback mechanisms.
Arsenic has no effect on glycolysis as it specifically targets mitochondrial enzymes.
Imagine a scenario where a cell expresses a mutated form of glyceraldehyde-3-phosphate dehydrogenase that uses inorganic phosphate but does not reduce NAD+ to NADH. What is the fate of the high-energy phosphate group acquired during this altered reaction in the subsequent steps of glycolysis under anaerobic conditions?
It is lost as inorganic phosphate during the conversion to 2-phosphoglycerate.
It is transferred to ADP to form ATP by phosphoglycerate kinase.
It remains attached to the 3-carbon molecule and is ultimately incorporated into lactate.
It is used to phosphorylate another glucose molecule, priming it for entry into glycolysis.
What is the relationship between the volume of consumed and the volume of produced during the complete oxidation of tripalmitin?
The volume of produced is less than the volume of consumed.
The volume of produced is equal to the volume of consumed.
The volume of produced is greater than the volume of consumed.
There is no relationship between the volumes.
