3A Reproduction

Question 1

What is the difference between asexual reproduction and sexual reproduction?

Answer 1

• Asexual reproduction involves mitosis to produce genetically identical copies
• Sexual reproduction involves the combination of sperm and egg cells to create a zygote

Question 2

What is the difference between a zygote and an embryo?

Answer 2

The zygote is the diploid cell formed from the fusion of a sperm and egg cell, it becomes an embryo after it begins to divide.

Question 3

1 adavantage and 1 disadvantage of sexual reproduction

Answer 3

Adv - it introduces variation
Disadv- it is slower and produces limited amount of offspring

Question 4

1 advantage and 1 disadvantage of asexual reproduction

Answer 4

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

Question 5

3 features of insect pollinated plants

Answer 5

• Bright coloured flowers
• Sweet nectar
• Sticky pollen

Question 6

3 features of wind pollinated plants

Answer 6

• No bright colours
• Stigma exposed to the air
• Light pollen

Question 7

Describe the process of fertilisation in plants

Answer 7

• Pollen grain lands on the stigma
• Pollen tube begins to grow from the pollen grain into the ovary
• Pollen grain travels down the pollen tube and fertilizes the egg
• Fruit and seeds form from the egg

Question 8

How can seeds grow before they can photosynthesise?

Answer 8

They use energy stores of starch

Question 9

Give one natural example of plant cloning

Answer 9

Plant runners from strawberries and spider plants.

Question 10

Give one artificial example of plant cloning

Answer 10

Tissue cuttings placed in a growth medium

Question 11

What does oestrogen do?

Answer 11

Builds up uterus linning

Question 12

Where is oestrogen secreted from?

Answer 12

The ovaries

Question 13

What hormone does oestrogen inhibit?

Answer 13

follicle stimulating hormone (FSH)

Question 14

What does progesterone do?

Answer 14

Progesterone maintains the womb lining

Question 15

Where is progesterone secreted from?

Answer 15

The ovaries

Question 16

What hormone does progesterone inhibit?

Answer 16

Follicle stimulating hormone (FSH).

Question 17

Where are eggs produced?

Answer 17

In the ovaries

Question 18

How are egg cells adapted to their function?

Answer 18

• They are very large cells
• They contain a large cytoplasm for the lots of divisions they undergo
• They have a haploid nucleus

Question 19

How are sperm cells adapted to their function?

Answer 19

• Acrosome contains enzymes so the sperm can penetrate the egg
• Haploid nucleus
• Tail so that it can swim to the egg
• Lots of mitochondria for energy

Question 20

What is the purpose of amniotic fluid?

Answer 20

To protect the developing fetus

Question 21

What is the purpose of the placenta

Answer 21

To allow nutrients and oxygen to pass from the mother to the fetus during development

Question 22

What role does oestrogen play during puberty

Answer 22

• Increases breast size
• Triggers the development of the uterus
• It causes eggs to mature during the menstrual cycle

Question 23

What role does testosterone play during puberty?

Answer 23

• Triggers growth and development of the penis and testes
• Causes the voice to deepen
• Triggers the growth of pubic hair
• Increases muscle mass