Question

Match the columns.

Sr. no.	I		II
1.	Sickle cell anemia	a.	7th chromosome
2.	Phenylketonuria	b.	4th chromosome
3.	Cystic fibrosis	c.	11th chromosome
4.	Huntington's disease	d.	X-chromosome
5.	Colour blindness	e.	12th chromosome

• A. 1- a, 2- c, 3- d, 4- b, 5- e
• B. 1- c, 2- e, 3- a, 4- b, 5- d
• C. 1- d, 2- e, 3- d, 4- e, 5- a
• D. 1- b, 2- a, 3- c, 4- e, 5- d
• E. 1- d, 2- e, 3- c, 4- b, 5- a

Answer 1

The correct option is B 1- c, 2- e, 3- a, 4- b, 5- d

• Sickle cell anemia is caused by a point mutation in the beta chain of hemoglobin where glutamic acid is replaced by valine at the 6th position of the 11th chromosome.
  
• Phenylketonuria is caused by a defect in the gene present on the 12th chromosome that codes for phenylalanine hydroxylase enzyme. In the absence of this enzyme, the body cannot break phenylalanine and hence leads to its accumulation.
  
• Cystic fibrosis occurs due to a mutation in both copies of the gene on the 7th chromosome for the CFTR (cystic fibrosis transmembrane conductance regulator) protein. This disorder leads to lung infections.
  
• Huntington's disease is caused due to an increased number of CAG trinucleotide repeats on chromosome 4.
  
• Colour blindness is X linked disorder where an individual loses its ability to distinguish between red and green colour. the mutations occur on the 23rd chromosome which is known as sex chromosome because it determines the sex of the individual.
  

So, the correct option is '1- c, 2- e, 3- a, 4- b, 5- d'.