Topic 16

Question 1

What is asexual reproduction?

Answer 1

The production of genetically identical offspring from one parent

Question 2

Give one advantage and one disadvantage of asexual reproduction

Answer 2

Advantage - It produces lots of offspring quickly
Disadvantage - It does not introduce variation and so all offspring are susceptible to the same environmental pressures as the parents

Question 3

What is sexual reproduction?

Answer 3

The production of genetically different offspring from the fusion of the nuclei from two gametes

Question 4

Define fertilisation

Answer 4

The fusion of the nuclei from two gametes (sex cells)

Question 5

State the difference in the number of chromosomes in a gamete nucleus compared with a zygote nucleus

Answer 5

Gametes have haploid nuclei (23 chromosomes) whereas zygotes have diploid nuclei (23 pairs of chromosomes)

Question 6

Give one advantage and one disadvantage of sexual reproduction

Answer 6

“Advantage - It introduces variation
Disadvantage - It is slower and produces a limited amount of offspring”

Question 7

What is the function of the sepals in an insect pollinated plant?

Answer 7

The sepal is a hard coating that protects the developing flower in a bud

Question 8

What is the function of the petals in an insect pollinated plant?

Answer 8

The petals attract the insects so that they can pollinate the plant

Question 9

What is the function of the anthers in an insect pollinated plant?

Answer 9

The anthers contain the pollen sacs which contain the male sex cells of the plant

Question 10

What is the function of the stigma in an insect pollinated plant?

Answer 10

These are the sticky parts of the plant designed to capture the pollen grains

Question 11

What is the function of the ovaries in an insect pollinated plant?

Answer 11

They contain ovules which will grow into seeds when they are fertilised by pollen

Question 12

What is pollination?

Answer 12

Where pollen grains are transferred from the anthers to the stigma

Question 13

What is self-pollination?

Answer 13

Where pollen grains are transferred from the anthers to the stigma of the same plant

Question 14

What is cross-pollination?

Answer 14

Where pollen grains are transferred from the anthers of one plant to the stigma of another plant of the same species

Question 15

Give one advantage of self-pollination

Answer 15

There is a greater chance of fertilisation as it does not rely on pollinators

Question 16

Give one disadvantage of self-pollination

Answer 16

Genetic variation decreases and the plant is less able to adapt to the environment

Question 17

Give one advantage of cross-pollination

Answer 17

The plants are more able to adapt to environmental changes and there is increased genetic variation

Question 18

Give one disadvantage of cross-pollination

Answer 18

The plants are reliant on insect populations for fertilisation

Question 19

Describe what happens when a pollen grain lands on the stigma of a plant

Answer 19

“A pollen tube grows through the style & into ovule in the ovary
Male nucleus travels travels down the pollen tube & into egg cell
Male nucleus fuses w/ female = fertilisation

Question 20

When does fertilisation occur?

Answer 20

When the nucleus of a pollen grain fuses with the nucleus of an ovule

Question 21

State 3 environmental conditions that affect seed germination

Answer 21

“Oxygen availability
Water availability
A suitable temperature”

Question 22

Define germination

Answer 22

Development of a plant from a seed after a period of dormancy