biology : class11 Fruit Size Enlargement : Functions, Effects, Applications : Gibberellin MCQ Questions and Answers
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Fruit Size Enlargement
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MCQ Questions
1. Which treatment most directly exploits gibberellin-mediated fruit enlargement in seedless table grapes?
A.
Applying gibberellin to the inflorescence before anthesis and again to developing berries
B.
Applying gibberellin only to mature leaves after fruit harvest
C.
Applying gibberellin to dormant roots before irrigation begins
D.
Applying gibberellin only after the berries have completed ripening
Correct Answer:
Applying gibberellin to the inflorescence before anthesis and again to developing berries
Explanation:
Pre-bloom gibberellin treatment can help loosen the bunch and induce seedlessness, while treatment during early berry development promotes enlargement of the developing grapes.
2. A developing fruit increases substantially in size after gibberellin application despite having few or no viable seeds. Which explanation best accounts for this observation?
A.
Gibberellin can stimulate fruit growth independently of the growth contribution normally associated with developing seeds
B.
Gibberellin converts every seed into a mature embryo before fruit growth begins
C.
Gibberellin enlarges fruits only by increasing the number of ovules present in the ovary
D.
Gibberellin prevents fruit tissues from responding to all other plant hormones
Correct Answer:
Gibberellin can stimulate fruit growth independently of the growth contribution normally associated with developing seeds
Explanation:
Seeds commonly provide growth-promoting signals, but gibberellin supplied externally can promote fruit enlargement even when seed development is absent or greatly reduced.
3. Two genetically similar grape bunches receive equal gibberellin doses. Bunch X is treated during early berry development, whereas bunch Y is treated after berries have nearly reached mature size. What result is most likely?
A.
Bunch X shows greater berry enlargement because its tissues are actively undergoing growth
B.
Bunch Y shows greater enlargement because mature berries absorb hormones more rapidly
C.
Both bunches show identical enlargement because timing does not influence gibberellin action
D.
Neither bunch enlarges because gibberellin acts only on roots and stems
Correct Answer:
Bunch X shows greater berry enlargement because its tissues are actively undergoing growth
Explanation:
Gibberellin is most effective for fruit enlargement when applied during active fruit development; nearly mature fruits generally have less capacity for hormone-stimulated expansion.
4. Which cellular change most directly contributes to gibberellin-induced enlargement of a developing fruit?
A.
Increased expansion of fruit cells, often accompanied by enhanced cell growth
B.
Permanent conversion of fruit cells into pollen-producing cells
C.
Complete replacement of fruit tissues by vascular bundles
D.
Suppression of all water uptake by the fruit
Correct Answer:
Increased expansion of fruit cells, often accompanied by enhanced cell growth
Explanation:
Fruit size increases when gibberellin promotes growth of the existing fruit tissues, particularly through cell expansion and, in some fruits, additional cell proliferation.
5. A farmer applies an excessive concentration of gibberellin to young fruit. Which outcome most directly indicates that the treatment has exceeded the useful range for fruit enlargement?
A.
Abnormally elongated, misshapen fruits with reduced market quality
B.
Uniformly normal fruits with exactly the same size as untreated fruits
C.
Immediate transformation of fruits into roots
D.
Complete prevention of fruit tissue expansion at every concentration
Correct Answer:
Abnormally elongated, misshapen fruits with reduced market quality
Explanation:
Gibberellin responses are concentration-dependent. Excessive treatment can produce abnormal elongation or shape and therefore reduce the commercial quality of enlarged fruits.
6. Why is gibberellin treatment particularly valuable for enlarging seedless grapes?
A.
It can enlarge berry tissues while maintaining the desirable absence of mature seeds
B.
It causes every seedless berry to develop a large number of viable seeds
C.
It enlarges only the seeds, leaving the surrounding berry unchanged
D.
It prevents the berries from undergoing any further growth after treatment
Correct Answer:
It can enlarge berry tissues while maintaining the desirable absence of mature seeds
Explanation:
Gibberellin is used commercially in seedless grapes because it can promote berry enlargement without requiring the development of mature seeds.
7. In an experiment, fruit diameter is measured after applying gibberellin to one group and water to a control group. Which additional observation would provide the strongest evidence that gibberellin specifically promoted fruit enlargement?
A.
The treated fruits have greater diameter while fruit number and developmental stage are comparable between groups
B.
The treated plants have taller stems but fruit diameter is not measured
C.
The treated plants produce more leaves but no fruit-size data are collected
D.
The control fruits are harvested earlier than the treated fruits
Correct Answer:
The treated fruits have greater diameter while fruit number and developmental stage are comparable between groups
Explanation:
Comparable fruit number and developmental stage reduce alternative explanations, so a greater diameter in treated fruits more directly supports gibberellin-induced enlargement.
8. A fruit crop responds weakly to gibberellin when sprayed after visible ripening has begun. Which conclusion is most appropriate?
A.
Gibberellin is generally more effective for enlargement before or during active fruit growth than after ripening
B.
Gibberellin can enlarge fruits only when applied to roots rather than fruits
C.
Ripening permanently converts gibberellin into a substance that destroys fruit cells
D.
Gibberellin has no role in fruit enlargement under any developmental condition
Correct Answer:
Gibberellin is generally more effective for enlargement before or during active fruit growth than after ripening
Explanation:
Fruit tissues have greater growth potential before and during active development. Once ripening begins, their capacity for further gibberellin-stimulated enlargement is usually reduced.
9. Which comparison best distinguishes gibberellin-induced fruit enlargement from a mere increase in fruit number?
A.
Measuring average fruit size separately from total fruit number in treated and untreated plants
B.
Counting leaves without measuring any fruits
C.
Measuring plant height only after harvest
D.
Recording seed color without recording fruit dimensions
Correct Answer:
Measuring average fruit size separately from total fruit number in treated and untreated plants
Explanation:
Fruit enlargement concerns the size of individual fruits. Measuring average fruit size independently from fruit number determines whether gibberellin increased fruit dimensions rather than merely fruit production.
10. A gibberellin-treated fruit becomes larger because its cells expand, but its dry mass increases only slightly. Which interpretation is most consistent with this result?
A.
The apparent enlargement includes increased water-associated expansion of fruit tissues
B.
Gibberellin must have reduced the physical volume of the fruit
C.
The fruit enlarged only because its seeds multiplied rapidly
D.
Dry mass and fruit volume must always increase in exactly the same proportion
Correct Answer:
The apparent enlargement includes increased water-associated expansion of fruit tissues
Explanation:
Cell expansion involves increased tissue volume and often greater water uptake. Therefore, fruit size can rise substantially without a proportional increase in dry matter.
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