Plant Physiology – Respiration & Germination Quiz - ICSE Class 9 Biology
Free practice quiz: Plant Physiology – Respiration & Germination (ICSE Class 9 Biology). 49 multiple-choice questions with answers and explanations. Play online, no sign-up needed.
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Which of the following processes in plants directly utilizes atmospheric oxygen as a reactant?
- Photosynthesis
- Transpiration
- Aerobic Respiration
- Nitrogen Fixation
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Answer: C. Aerobic Respiration
Aerobic respiration is a metabolic process that occurs in the presence of oxygen, where glucose is broken down to produce ATP, carbon dioxide, and water. Photosynthesis consumes carbon dioxide and releases oxygen. Transpiration is the loss of water vapor from plants. Nitrogen fixation is the conversion of atmospheric nitrogen into ammonia.
When fats are respired, the respiratory quotient (RQ) is typically:
- Equal to 1
- Greater than 1
- Less than 1
- Zero
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Answer: C. Less than 1
Fats are more reduced compounds than carbohydrates and require more oxygen for their complete oxidation. For example, the respiration of tripalmitin (a fat) yields an RQ of approximately 0.7. This means more oxygen is consumed than carbon dioxide is produced.
Which of the following describes the energy yield during anaerobic respiration compared to aerobic respiration?
- Anaerobic respiration yields more ATP.
- Anaerobic respiration yields less ATP.
- Both yield the same amount of ATP.
- ATP yield is negligible in both.
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Answer: B. Anaerobic respiration yields less ATP.
Anaerobic respiration only involves glycolysis, producing a net of 2 ATP molecules. Aerobic respiration, including glycolysis, the Krebs cycle, and the electron transport chain, yields significantly more ATP (around 30-32).
In the context of respiration, the energy stored in glucose is released and captured in the form of:
- Heat energy
- Light energy
- Mechanical energy
- Chemical energy (ATP)
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Answer: D. Chemical energy (ATP)
Cellular respiration breaks down glucose through a series of steps, releasing energy that is then used to synthesize ATP (adenosine triphosphate), the primary energy currency of the cell.
During the germination of a dicotyledonous seed, the cotyledons are typically:
- Consumed entirely before the plumule emerges
- The primary sites of photosynthesis immediately after emergence
- Degraded and absorbed by the embryo
- The first structures to emerge from the seed coat
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Answer: C. Degraded and absorbed by the embryo
Cotyledons serve as storage organs for food reserves. Once the embryo begins to grow, these reserves are broken down and absorbed by the developing seedling.