UPSC Prelims 2013 Q86: Science & Technology – Biology
Fruits stored in a cold chamber exhibit longer storage life because
- (a) exposure to sunlight is prevented
- (b) concentration of carbon dioxide in the environment is increased
- (c) rate of respiration is decreased
- (d) there is an increase in humidity
Answer: (c) rate of respiration is decreased
Explanation
Why fruits last longer in a cold chamber
A harvested fruit is still alive and keeps respiring.
Respiration uses up its sugars and leads to ripening and decay.
Low temperature slows respiration, so the fruit lasts longer.
| Option | Verdict | Reason |
|---|---|---|
| (a) Exposure to sunlight is prevented | Incorrect | Darkness alone does not preserve fruit |
| (b) Concentration of carbon dioxide is increased | Incorrect | That is controlled atmosphere storage, a different method |
| (c) Rate of respiration is decreased | Correct | Cold slows all enzyme activity |
| (d) There is an increase in humidity | Incorrect | High humidity can even promote rot |
What cold storage does:
| Effect | Result |
|---|---|
| Slower respiration | Sugars last longer |
| Less ethylene action | Slower ripening |
| Slower growth of microbes | Less spoilage |
Answer: (c) rate of respiration is decreased.
Why each option is right or wrong
- (a) Incorrect. Keeping out sunlight is not the reason for longer life.
- (b) Incorrect. Raising carbon dioxide is a separate storage technique.
- (c) CORRECT. Cold lowers the rate of respiration, so the fruit keeps longer.
- (d) Incorrect. Humidity is not the reason; too much of it causes rot.
Key point
Cold storage slows respiration, ripening (ethylene) and microbial growth in harvested fruit; controlled atmosphere storage adds CO2 and lowers oxygen.
Remember
Cold storage = slower respiration.
Common mistakes
- Confusing cold storage with controlled atmosphere storage.
- Forgetting that a picked fruit is still respiring.
- Thinking cold kills microbes; it only slows them.
Exam tip
Cold slows every life process. Slower respiration means slower ageing of the fruit.
Sources
- NCERT Class XI — Biology (Respiration in Plants)
- National Centre for Cold-chain Development — Guidelines on cold storage of fruits and vegetables