B6 Reproduction (page 69)

Question 1

Reproduction can happen in TWO different ways, what are they?

Answer 1

Sexual Reproduction

and,

Asexual Reproduction

Question 2

What is Sexual Reproduction?

Answer 2

it is where genetic information from two organisms (a father and a mother) is combined to produce offspring which are genetically different to either parent.

Question 3

In sexual reproduction, the mother and father produce what by meiosis?

Answer 3

the mother and father produce Gametes by Meiosis (see page 70)

e.g. egg and sperm cells in animals.

Question 4

In humans, each gamete contains how many chromosomes?

Answer 4

23 chromosomes - half the number of chromosomes in a normal cell. (instead of having two of each chromosome, a gamete has just one of each).

Question 5

The egg (from the mother) and the sperm cell (from the father) fuse together (fertilisation) to form what?

Answer 5

a cell with the full number of chromosomes (half from the father, half from the mother).

Question 6

Sexual reproduciton involves what?

Answer 6

the fusion of male and female gametes.

(because there are TWO parents, the offspring contain a mixture of their parents’ genes..

see diagram of fertilisation on page 69.

Question 7

Why do the offspring interit features from both parents?

Answer 7

it receives a mixture of chromosomes from its mum and its dad (and its the chromosomes that decide how you turn out).

Question 8

The mixture of genetic information produces what?

Answer 8

a variation in the offspring.

Question 9

Flowering plants can reproduce in this way too, how?

Answer 9

they also have egg cells, but their version of sperm is known as pollen.

Question 10

Sexual Reproduction produces what?

Answer 10

genetically different cells.

Question 11

Asexual Reproduction produces what?

Answer 11

genetically identical cells.

Question 12

What is Asexual reproduction?

Answer 12

there’s only one parent so the offspring are genetically identical to that parent.

Question 13

How does Asexual reproduction happen?

Answer 13

it happens by Mitosis - an ordinary cell makes a new cell by dividing in two (see page 15).

The new cell has exactly the same genetic information (i.e. genes) as the parent cell - it’s called a clone.

Question 14

Explain Asexual Reproduction?

Answer 14

There’s only ONE parent, there’s no fusion of gametes, no mixing of chromosomes and no genetic variation between parent and offspring.

The offspring are genetically identical to the parent - they’re clones.

Question 15

what can reproduce asexually?

Answer 15

Bacteria, some plants and some animals reproduce asexually.

Question 16

What is sexual reproduction?

Answer 16

needs two parents and forms cells that are genetically different to the parents, so there’s lots of genetic variation.

Question 17

What is Asexual reproduction?

Answer 17

needs just one parent to make genetically identical cells, so there’s no genetic variation in the offspring.

Question 18

NitosisWhat type of cell division is involved in asexual reproduction (1 mark)?

Answer 18

Mitosis (1 mark)

Question 19

Suggest why there is variation in the offspring of sexual reproduction (2 marks)

Answer 19

Because there are two parents, the offspring contain a mixture of their parents’ genes (1 mark). This mixture of genetic information produces variation ( mark)