Question

Sickle cell disease is caused by a:

A. change in one allele.

B. change in the size of a chromosome.

C. change in two proteins.

D. change in the number of chromosomes in a cell.

Answer 1

It's C.

Answer 2

emcrazy - which two
i think its a. one allele the conveys a relative protection against malaria (hence the selection benefit for the existence of this disease)

Answer 3

its A, coz sickle cell anaemia is cause by a recessive allele...

Answer 4

@ttom I'm not sure. Sickle cell is caused by two recessive alleles. Beta globin is affected. If only one of the beta globin genes is the "sickle" gene and the other is normal, the person is a carrier for sickle cell disease.

Answer 5

@emcrazy14 - ur right.
one allele carries the advantage. homozygosity - the disease. cheers!

Answer 6

I don't see a correct answer here. Maybe the word "allele" is being used in an unusual way in this question?

Answer 7

The closest answer is A . Emmcrazy is correct.

Answer 8

@jc7 Yea. I think the same. Maybe the person made some mistake when writing the question.