B3d Divide & Rule Answer Higher

B3d Divide & Rule Answer

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  • Created on: 14-05-12 10:53
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B3d Divide and Rule
1. Structure of a sperm cell is adapted to its function:
small size and tail
nucleus carries genes
produced in large numbers to increase chance of fertilisation.
Structure of an egg cell is adapted to its function:
large size as contains food source (for the growing embryo)
nucleus carries genes.
2. The differences between a sperm cell and an egg cell are:
The sperm cell has a tail so that it can swim to egg
It is also smaller in size compared to the egg so that can produce in large numbers
and it would be easy to swim.
The egg cell is much larger than the sperm cell as it stores food.
3. Describe the growth of an embryo, with cell division ideas: After fertilization an egg
cell develops into an embryo. Cells divide so the embryo grows bigger in size.
Cells also differentiate produce many different types of special cells to make the
new organism.
4. Lots of sperm cells are produced at the same time. Explain why?
So there is a higher chance of fertilisation
5. kangaroos have 12 chromosome in the skin cell. How many chromosomes are in
a sperm cell from a kangaroo? 6
Higher only:
6. This question is about human growth.
(a) The diagram shows a sperm cell.
(i) Sperm cells are adapted to fertilise egg cells.
Explain how the acrosome is an adaptation for fertilisation.
Acrosome contains enzymes that can digest and a dissolve the outer layer
of the egg, so the sperm can go in.
(ii) Some sperm cells have more mitochondria than others.
Would you expect sperm cells with more mitochondria than
others to have a greater chance of fertilising an egg? Explain
your answer.

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Would they have a greater chance of fertilising an egg? Yes
Explanation mitochondria produces the energy needed for the sperm cell.
If there are more mitochondria the sperm cells will have more energy so
they can swim faster towards the egg
(b) The diagram shows a fertilised egg cell dividing.
What type of cell division does the diagram show? Mitosis (as it is
a fertilised egg)
(c) The graph shows how the mass of a boy changes as he grows.…read more

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Kangaroos have 12 chromosomes in each skin cell.
How many chromosomes are in a sperm cell from a kangaroo?
6
(ii) How many chromosomes are in a kidney cell from a kangaroo?
12
(b) Look at the diagrams of cell division.
(i) Which diagram describes meiosis?
Choose A, B, C or D.
D
(ii) Which diagram describes mitosis?
Choose A, B, C or D.
A
10.…read more

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