reproduction (part 3)

Question 1

What is the function of the sepal?

Answer 1

Encloses and protects the flower bud

Question 2

What is the function of petals?

Answer 2

They are often colourful and fragrant to attract insects and other pollinators to the flower

Question 3

What are the reproductive structures in a flower?

Answer 3

• Anther + filament: stamen
• Style + stigma: carpel
• Ovary

Question 4

What is pollination? What are the 2 types of pollination?

Answer 4

Pollination is the transfer of pollen grains from an anther to a stigma.

• Self-pollination
• Cross-pollination

Question 5

Distinguish between self and cross-polination.

Answer 5

Self-pollination is the transfer of pollen grains from the anther to the stigma of the same flower/a different flower on the same plant
Cross-pollination is the transfer of pollen grains from one plant to the stigma of another plant of the same species.

Question 6

Pollen grains on the stigma ____ in response to the sugary fluid produced by the mature stigma.

Answer 6

Pollen grains on the stigma germinate in response to the sugary fluid produced by the mature stigma.

Question 7

A ____ ___ grows out from the pollen grain and the male gamete forms in the tube. As the pollen tube grows, it secretes ____ to digest the tissue of the stigma and style. The pollen tube grows down the ___.

Answer 7

A pollen tube grows out from the pollen grain and the male gamete forms in the tube. As the pollen tube grows, it secretes enzymes to digest the tissue of the stigma and style. The pollen tube grows down the style.

Question 8

The pollen tube enters the ovule through an opening in the ovule wall called the ______. Within the ovule, the tip of the pollen tube absorbs sap and bursts, releasing the __ (number) male gametes. The nucleus of one of the male gametes fuses with the nucleus of the ovum to form the ___ (fertilisation).

Answer 8

The pollen tube enters the ovule through an opening in the ovule wall called the micropyle. Within the ovule, the tip of the pollen tube absorbs sap and bursts, releasing the two male gametes. The nucleus of one of the male gametes fuses with the nucleus of the ovum to form the zygote (fertilisation).

Question 9

Where is the male and female gamete in plants?

Answer 9

Male gamete: pollen grain

Female gamete: ovum (inside the ovule)

Question 10

List down characteristics of insect-pollinated flowers.

Answer 10

• Large, brightly coloured petals
• Nectar is present, flowers are fragrant/sweet-smelling
• Small, compact stigma that does not protrude out of the flower
• Stamens are not pendulous and usually do not protrude out of the flower
• Pollen is fairly abundant, larger with rough surfaces so that they can cling onto the body of the insect
• Nectar guide may be present on petals to guide insects towards nectar

Question 11

List down characteristics of wind-pollinated flowers.

Answer 11

• Petals are dull and small (or no petals at all)
• Nectar is absent
• Flowers are odourless
• Stigmas are large, feathery and usually protrude out of the flower (larger surface area to trap pollen)
• Abundance of pollen. Tiny and light so that they are easily blown about by wind
• Nectar guide is absent