Respiration in Plants for NEET UG
Respiration releases the energy stored in food and traps it as ATP. Glucose is broken down in stages (glycolysis, the Krebs cycle and the electron transport chain), each in its own part of the cell.
BiologyClass 1171 MCQs2 lessons13 flashcards3 memory tricks
Practise Respiration in Plants free
What you'll learn
- Glycolysis and fermentation
Describe glycolysis and what happens to pyruvate with and without oxygen. - Krebs cycle, electron transport and ATP yield
Trace aerobic respiration and calculate ATP produced; use the respiratory quotient.
Key formulas
| ATP per NADH / FADH₂ (NCERT) | 3 / 2 |
|---|---|
| Net ATP per glucose (NCERT) | 38 |
| Respiratory quotient | RQ = CO₂ released / O₂ used |
Memory tricks
Glycolysis in the cytoplasm, Krebs cycle in the mitochondrial matrix, electron transport and ATP synthesis on the inner mitochondrial membrane.
Alcoholic fermentation (yeast): glucose → ethanol + CO₂. Lactic acid fermentation (muscles, Lactobacillus): pyruvate → lactic acid.
RQ = CO₂ released ÷ O₂ used. Carbohydrates 1, fats about 0.7 (tripalmitin 0.7), proteins about 0.9, organic acids more than 1, anaerobic respiration infinite.
Try 3 NEET-style questions
Q1. Cytochrome c in the electron transport system is
- a small mobile protein carrying electrons from complex III to IV
- a large enzyme embedded in the outer mitochondrial membrane
- the final acceptor of electrons at the end of the chain
- the site where ATP is synthesised from ADP and phosphate
Show answer
Answer: (1) a small mobile protein carrying electrons from complex III to IV
Cytochrome c is a small protein attached to the outer surface of the inner membrane that acts as a mobile carrier between complex III and complex IV.
Q2. Pyruvic acid is converted to acetyl CoA with release of CO₂ and formation of NADH. This link reaction takes place in the
- cytoplasm
- mitochondrial matrix
- outer mitochondrial membrane
- thylakoid lumen
Show answer
Answer: (2) mitochondrial matrix
Pyruvate enters the mitochondrion, and pyruvate dehydrogenase converts it to acetyl CoA in the matrix.
Q3. The number of ATP molecules used up in glycolysis for each molecule of glucose is
- 4
- 1
- 6
- 2
Show answer
Answer: (4) 2
ATP is used twice: glucose to glucose-6-phosphate, and fructose-6-phosphate to fructose-1,6-bisphosphate. Four ATP are made, so the net gain is 2.
Practise all 71 questions Free · explanations for every option · see where you go wrong