Quick Review Flashcards - Click to flip and test your knowledge!
Question
What is the botanical definition of a fruit?
Answer
A ripened ovary.
Question
What is the botanical definition of a seed?
Answer
A ripened ovule.
Question
How is a 'grain' defined in botany?
Answer
A fruit in which the fruit wall and seed coat are fused together.
Question
Which part of the seed protects the embryo from mechanical damage?
Answer
The seed coat.
Question
The embryo is developed from the fusion of the egg nucleus and the _____ nucleus.
Answer
Sperm
Question
Which part of the embryo is the precursor to the root system?
Answer
The radicle.
Question
Which part of the embryo is the precursor to the shoot system?
Answer
The plumule.
Question
What is the term for the 'seed leaves' found within an embryo?
Answer
Cotyledons.
Question
What is the term for the inactive state in which a seed remains until it encounters favourable conditions?
Answer
Dormancy.
Question
What tissue provides food material for the nourishment of the embryo during germination in some seeds?
Answer
Endosperm.
Question
Give an example of a plant that produces some of the largest known seeds.
Answer
Double coconut (or coconut).
Question
What is the primary characteristic of 'albuminous' seeds?
Answer
The endosperm persists and the cotyledons are thin and membranous.
Question
What is the primary characteristic of 'exalbuminous' seeds?
Answer
The cotyledons store food and become thick and fleshy, as the endosperm is absent.
Question
How are seeds classified based on the number of cotyledons they possess?
Answer
Monocotyledonous (one cotyledon) and dicotyledonous (two cotyledons).
Question
Which hard, brownish outer layer of the bean seed coat protects the inner parts from injury?
Answer
The testa.
Question
What is the name of the thin, inner layer of the seed coat lying next to the testa?
Answer
The tegmen.
Question
What is the name of the distinct whitish oval scar on the concave side of a bean seed?
Answer
The hilum.
Question
What is the primary function of the micropyle regarding water?
Answer
It allows the seed to absorb water for germination.
Question
Besides water absorption, what is the second function of the micropyle?
Answer
It provides for the diffusion of respiratory gases for the growing embryo.
Question
In a bean seed, where is the food for the embryo stored?
Answer
In the two thick cotyledons.
Question
What term describes the region of the embryo axis located between the point of attachment of cotyledons and the plumule?
Answer
The epicotyl.
Question
What term describes the region of the embryo axis located below the point of attachment of cotyledons?
Answer
The hypocotyl.
Question
Why is a maize grain technically a fruit rather than just a seed?
Answer
The fruit wall and the seed coat are fused together.
Question
What is the protein-rich outermost layer of the endosperm in a maize grain called?
Answer
The aleurone layer.
Question
What is the specific name for the single cotyledon found in a maize embryo?
Answer
The scutellum.
Question
In maize, which protective sheath encloses the radicle?
Answer
The coleorhiza.
Question
In maize, which protective sheath encloses the plumule?
Answer
The coleoptile.
Question
How does the plumule of a bean seed differ from that of a maize grain?
Answer
The bean plumule has folded leaves, while the maize plumule has rolled leaves.
Question
What is the physiological process of formation of a seedling developed from the embryo?
Answer
Germination.
Question
What are the three essential external conditions required for seed germination?
Answer
Water, suitable temperature, and air (oxygen).
Question
Why is water necessary for the chemical reactions within a germinating seed?
Answer
It converts stored food into a diffusable (dissolved) form for the embryo.
Question
What is the generally favourable temperature range for seed germination, known as the optimum temperature?
Answer
$25^\circ \text{C}$ to $35^\circ \text{C}$.
Question
Why is oxygen (air) essential during the process of germination?
Answer
It is required for respiration to provide energy for rapid cell division and growth.
Question
Why do seeds sown very deep in the soil often fail to germinate?
Answer
There is an insufficient supply of oxygen for respiration.
Question
Which chemical is used in experiments to prove that oxygen is necessary for germination because it absorbs the gas?
Answer
Alkaline pyrogallic acid.
Question
In the 'three-bean experiment', why does the bottom seed usually fail to germinate properly?
Answer
It gets water but very little oxygen from the air dissolved in water.
Question
In the 'three-bean experiment', why does the top seed fail to germinate?
Answer
It gets oxygen but no water.
Question
What type of germination occurs when the epicotyl elongates, keeping the cotyledons underground?
Answer
Hypogeal germination.
Question
What type of germination occurs when the hypocotyl elongates, pushing the cotyledons above the ground?
Answer
Epigeal germination.
Question
Give an example of a plant that undergoes hypogeal germination.
Answer
Pea (or gram, or maize).
Question
Give an example of a plant that undergoes epigeal germination.
Answer
Bean (or castor, or mustard).
Question
In pea germination, what function do the cotyledons serve before they wither?
Answer
They supply food to the seedling until it can exist independently.
Question
What happens to the cotyledons of a bean seed after they are pushed above ground during germination?
Answer
They become the first green leaves and eventually fall off.
Question
In maize germination, which part of the embryo axis does NOT elongate?
Answer
The hypocotyl.
Question
What is 'viviparous germination'?
Answer
A process where the seed germinates while still attached to the parent plant.
Question
Name a plant that exhibits viviparous germination.
Answer
Rhizophora (or Sonneratia).
Question
At what stage of growth does germination in a plant officially end?
Answer
With the formation of a seedling.
Question
What defines a plant as a 'seedling'?
Answer
It is a stage where the plant is not yet wholly independent of the food stored in the seed.
Question
What are the first structures of a seedling to absorb water and minerals from the soil?
Answer
The roots.
Question
Which part of a maize grain separates the endosperm from the embryonic part?
Answer
The epithelial layer.
Question
True or False: The grain of maize is an example of a monocotyledonous albuminous seed.
Answer
True.
Question
Based on the number of cotyledons, how is a mango seed classified?
Answer
Dicotyledonous (dicot).
Question
Why is the plumule of a germinating pea arched in the early stages?
Answer
To protect the young shoot from injury as it emerges from the soil.
Question
In a bean seed, what structure represents the spot where the ovule was attached to the ovary wall?
Answer
The hilum.
Question
Which part of the embryonic axis elongates faster in epigeal germination?
Answer
The hypocotyl.