Topic 16 Flashcards

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1
Q

What is asexual reproduction?

A

The production of genetically identical offspring from one parent

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2
Q

Give one advantage and one disadvantage of asexual reproduction

A

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

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3
Q

What is sexual reproduction?

A

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

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4
Q

Define fertilisation

A

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

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5
Q

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

A

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

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6
Q

Give one advantage and one disadvantage of sexual reproduction

A

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

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7
Q

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

A

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

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8
Q

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

A

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

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9
Q

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

A

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

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10
Q

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

A

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

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11
Q

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

A

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

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12
Q

What is pollination?

A

Where pollen grains are transferred from the anthers to the stigma

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13
Q

What is self-pollination?

A

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

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14
Q

What is cross-pollination?

A

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

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15
Q

Give one advantage of self-pollination

A

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

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16
Q

Give one disadvantage of self-pollination

A

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

17
Q

Give one advantage of cross-pollination

A

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

18
Q

Give one disadvantage of cross-pollination

A

The plants are reliant on insect populations for fertilisation

19
Q

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

A

“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

20
Q

When does fertilisation occur?

A

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

21
Q

State 3 environmental conditions that affect seed germination

A

“Oxygen availability
Water availability
A suitable temperature”

22
Q

Define germination

A

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