Q1
(a) Complete the following passage
Chromosomes carry genetic information. Chromosomes are made up of
____________________ . Human body cells contain 46 chromosomes. There are
twenty-two matching pairs but the final pair does not always match. It is these two
that determine the gender, or sex, of the human. If you are a __________________
the final pair of chromosomes matches. If you are a ____________________
the final pair of chromosomes does not match.
(2)
(b) Draw a labelled diagram to show that there is an equal chance of parents producing
a baby boy or girl. Use the symbols X and Y for the chromosomes.
(4)
(Total 6 marks)
Q2.
Cells in the human body are specialised to carry out their particular function.
(a) The diagram shows a sperm cell.
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, The sperm cell is adapted for travelling to, then fertilising, an egg.
(i) How do the mitochondria help the sperm to carry out its function?
______________________________________________________________
______________________________________________________________
(1)
(ii) The nucleus of the sperm cell is different from the nucleus of body cells.
Give one way in which the nucleus is different.
______________________________________________________________
______________________________________________________________
(1)
(b) Stem cells from human embryos are used to treat some diseases in humans.
Explain why.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(2)
(Total 4 marks)
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