A laboratory investigated variation in human red blood cells using samples from anonymous volunteers. Fig. 1 shows normal cells and sickle-shaped cells. The...
Question 1 Report
A laboratory investigated variation in human red blood cells using samples from anonymous volunteers. Fig. 1 shows normal cells and sickle-shaped cells. The abnormal shape is caused by an inherited allele affecting haemoglobin.
(a) What molecule in red blood cells is affected in this condition? [1]
(b) Describe how an inherited allele can lead to cells with a different shape. [2]
(c) Give two reasons why a person should receive genetic counselling before a genetic test result is shared with relatives. [2]
Answer Details
(a) The affected molecule is haemoglobin. [1]
(b) An inherited allele changes the DNA code for a protein. In this condition, altered haemoglobin causes red blood cells to develop a different, sickle-like shape. [2]
(c) Relatives may also carry the allele, so a result can have implications for them. Genetic information may cause anxiety, people should choose whether they want to know results, and results should remain confidential. Any two valid reasons gain credit. [2]
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