Reproduction In Plants.

Question 1

What is a seed?

Answer 1

A seed is a fertilized mature ovule.

Question 2

There are, however, notable differences between seeds of different species. Name the differences.

Answer 2

Seeds are of different sizes, shapes, and colors depending on plant species.

Question 3

Why is the slowing down of life processes important?

Answer 3

This is important for the plant to be able to survive unfavorable environmental conditions because the seed germinates only when environmental conditions become conducive to growth.

Question 4

What slows down the life processes in seeds?

Answer 4

When the seed is dormant, life processes inside the seed are slowed down.

Question 5

What are the parts of the male reproductive system and female reproductive system in the parts of a flower?

Answer 5

• Male reproductive system = anther and filament.

- Female reproductive system = stigma, style, ovary and, ovule.

Question 6

Name the processes of plant reproduction (in order).

Answer 6

• Pollination.
• Growth of pollen tube.
• Fertilization.
• Fruit formation.
• Seed dispersal.
• Germination or Plant growth.

Question 7

What is pollination and what pollinates?

Answer 7

Pollination is the transfer of pollen from anther to stigma. Pollination can be by insects (e.g. bees) or wind.

Question 8

Name the parts pollen travels through to reach its destination?

Answer 8

Pollen travels from the stigma, down the style, and into the ovule of the plant.

Question 9

Why does a pollen tube grow?

Answer 9

A pollen tube develops to carry the pollen downward.

Question 10

Define fertilization (plant reproduction).

Answer 10

Fertilization means the nucleus of the male gamete (pollen) fuses with the nucleus of the female gamete (ovule) to form a seed.

Question 11

Where do seeds develop?

Answer 11

The seeds develop in the ovary, which later on becomes the fruit.

Question 12

What causes fruit formation?

Answer 12

The ovary ripens and forms a fruit. The fruit may contain a single seed or multiple seeds.

Question 13

Define seed dispersal and what can disperse seed?

Answer 13

Seed dispersal is the movement of seeds away from the parent plant by wind (e.g. dandelion), animal (e.g. fur, eaten), or explosion (e.g. msasa).

Question 14

Define germination or plant growth.

Answer 14

If the seed is embedded in the right kind of soil, it will germinate. A new plant grows out of the seed. A stem reaches upward, and roots go downward into the soil.

Question 15

What conditions do seeds need to germinate?

Answer 15

Seeds germinate when there is warmth, water, and oxygen, they do not need light to germinate because they are underground.

Question 16

What are the processes of germination?

Answer 16

• The seed rapidly absorbs water and then the seed coat or testa splits.
• The radical (first root) grows downwards into the soil. The plumule (first shoot) straightens and pushes above the soil.
• The first leaves emerge and photosynthesize.
• Soon new leaves and roots form, establishing the plant, and the cotyledons fall off.

Question 17

Name the 3 external parts of a seed.

Answer 17

• Testa (seed coat).
• Hilum.
• Micropyle.

Question 18

What is the testa?

Answer 18

The testa is the tough waterproof covering of a seed; protects the embryo and the food storage.

Question 19

What is the hilum?

Answer 19

The hilum is a large oval scar, that was once the place of attachment of the young seed to the ovary wall.

Question 20

What is the function of the micropyle?

Answer 20

The micropyle is to be an entrance through water and oxygen enter the seed for germination.

Question 21

Name the 7 internal parts of a seed

Answer 21

• Testa (seed coat).
• Plumule (shoot system).
• Radical (root system).
• Cotyledon (food storage).
• Micropyle.
• Hilum.
• Embryo (plumule + radical).

Question 22

What is the embryo and what does it comprise of?

Answer 22

The miniature plant found inside the seed: it comprises of three parts (the radicle, epicotyl and hypocotyl, and plumule).

Question 23

What are cotyledons?

Answer 23

The first true leaf (monocotyledon) or set of leaves (dicotyledons) that provide food for the seedling.

Question 24

Where do the cotyledons access food from and how dow long do they do this?

Answer 24

They access food from the seed until true leaves develop and start to photosynthesise.

Question 25

What is the plumule?

Answer 25

The plumule is the part of the embryo that grows the shoot system.

Question 26

What is the radical?

Answer 26

The radical is the part of the embryo that grows into the root system.

Question 27

What is the epicotyl?

Answer 27

The epicotyl is the part of the embryo that grows into the stem; found below the plumule.

Question 28

What is the hypocotyl?

Answer 28

The hypocotyl is the part of the embryo that grows into the stem; found above the radical.

Question 29

What is meant by dicotyledon?

Answer 29

Dicotyledons = two seed leaves e.g. avocado pip and bean seed, peas.

Question 30

What is meant by monocotyledon?

Answer 30

Monocotyledon = one seed leaf e.g. maize pip, which nourishes the seedling before the first true leaves emerge.

Question 31

Name two differences between monocotyledonous and dicotyledonous seeds.

Answer 31

• One cotyledon in the embryo and endosperm is large and stores food materials of monocotyledonous seeds.
• Two cotyledons in the embryo and the cotyledons contain the endosperm of dicotyledonous seeds.

Question 32

Name the 4 food tests.

Answer 32

• Starch.
• Benedict’s test.
• Biuret test for protein.
• Emulsion test for fats/oils.

Question 33

Name the results of a Starch test.

Answer 33

Starch: iodine solution turns blue-black.

Question 34

Name the results of Benedict’s test.

Answer 34

Benedict’s test: sugars turn blue → green → orange → red-brown.

Question 35

Name the results of the Biuret test for protein.

Answer 35

The Biuret solution turns purple.

Question 36

Name the results of the Emulsion test for fats/oils.

Answer 36

Fats + alcohol + water. Shake it and a white emulsion forms.

Question 37

Define endosperm.

Answer 37

The endosperm is whitish or yellowish in color and is a storage tissue that is abundant in starch.

Question 38

What diagrams need to be revised?

Answer 38

• Parts of a flower.
• Plant Reproduction Diagram.
• External Structure of a bean seed (page 68).
• Internal Structure of a bean seed (page 72).

Question 39

What is the testa’s function?

Answer 39

The testa reduces evaporation of water from the seed and protects it from disease and physical injuries.