SPM Science 2019, Paper 2 (Question 8)

Question 8:
Diagram 7 shows the karyotype of a girl with a chromosome mutation.

Diagram 7

(a) Based on Diagram 7,
(i) state the number of chromosome.
(ii) name the genetic disease suffered by the girl.

(b) State one physical characteristic of the girl.

(c) Klinefelter’s syndrome is a genetic disease which is caused by the same type of mutation as in Diagram 7.
Mark (√) the correct information for the Klinefelter’s syndrome.
• Has sex chromosome of XO     [     ]
• Has sex chromosome of XXY   [     ]
• A man                                       [     ]
• A woman                                  [     ]

(d) Colour blindness and haemophilia are genetic diseases that are controlled by  recessive gene on the X chromosome. These diseases are caused by mutation M. Name mutation M.

(a)(i) 47

(a)(ii) Down’s syndrome

(b) Mental retardation/ Wide distance between eyes/ Slanting eyes/ Protuding tongue

• Has sex chromosome of XXY    [  √  ]
• A man                                        [  √  ]

(d) Gene mutation

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