1. Which enzyme is synthesized in cereal grains in response to gibberellin during germination?
A.
Alpha-amylase
B.
Pepsin
C.
Lipase
D.
Cellulase
Correct Answer:
Alpha-amylase
Explanation:
Gibberellin stimulates the synthesis of alpha-amylase in germinating cereal grains.
2. In a germinating barley seed, gibberellin mainly stimulates alpha-amylase production in which tissue?
A.
Aleurone layer
B.
Root cap
C.
Leaf epidermis
D.
Vascular cambium
Correct Answer:
Aleurone layer
Explanation:
Gibberellin acts on the aleurone cells of cereal grains to induce alpha-amylase synthesis.
3. What is the main function of alpha-amylase during seed germination?
A.
Breaking down starch into simpler sugars
B.
Converting sugars into proteins
C.
Producing oxygen from water
D.
Forming the seed coat
Correct Answer:
Breaking down starch into simpler sugars
Explanation:
Alpha-amylase hydrolyses stored starch into simpler sugars that can provide energy to the growing embryo.
4. Which seed storage material is acted upon by alpha-amylase?
A.
Starch
B.
DNA
C.
Cellulose in the cell wall
D.
Chlorophyll
Correct Answer:
Starch
Explanation:
Alpha-amylase specifically breaks down starch stored in the endosperm of cereal grains.
5. During cereal seed germination, gibberellin is generally produced by the developing
A.
Embryo
B.
Seed coat
C.
Aleurone cell wall
D.
Mature leaf surface
Correct Answer:
Embryo
Explanation:
The developing embryo releases gibberellin, which signals aleurone cells to synthesize alpha-amylase.
6. The sugars released by alpha-amylase from stored starch are mainly used by the embryo for
A.
Growth and energy
B.
Producing pollen grains
C.
Making the seed coat waterproof
D.
Absorbing sunlight
Correct Answer:
Growth and energy
Explanation:
The sugars produced from starch digestion supply energy and nutrients for the growing seedling.
7. Which sequence correctly describes the role of gibberellin in a germinating cereal seed?
A.
Gibberellin stimulates aleurone cells to produce alpha-amylase
B.
Gibberellin converts alpha-amylase directly into starch
C.
Gibberellin prevents starch breakdown by aleurone cells
D.
Gibberellin destroys the embryo before germination
Correct Answer:
Gibberellin stimulates aleurone cells to produce alpha-amylase
Explanation:
Gibberellin acts as a signal from the embryo and induces alpha-amylase synthesis in aleurone cells.
8. Alpha-amylase synthesis induced by gibberellin is especially important in the germination of
A.
Cereal grains
B.
Mature woody stems
C.
Fully developed flowers
D.
Dry leaf surfaces
Correct Answer:
Cereal grains
Explanation:
The gibberellin-induced alpha-amylase response is a well-known feature of germinating cereal grains such as barley.
9. What would be most directly affected if gibberellin could not induce alpha-amylase synthesis in a germinating cereal seed?
A.
Breakdown of stored starch
B.
Formation of chlorophyll in mature leaves
C.
Opening of stomata in flowers
D.
Production of pollen in anthers
Correct Answer:
Breakdown of stored starch
Explanation:
Without gibberellin-induced alpha-amylase, stored starch would not be efficiently broken down into sugars for the embryo.
10. Why is gibberellin-induced alpha-amylase synthesis useful to a germinating seed?
A.
It makes stored food available to the embryo
B.
It stops the embryo from using stored food
C.
It changes proteins directly into chlorophyll
D.
It prevents the seed from absorbing water
Correct Answer:
It makes stored food available to the embryo
Explanation:
Alpha-amylase converts stored starch into soluble sugars, making food reserves available for embryo growth.
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