The genetic disease caused by the absence of an enzyme that breaks down phenylalanine is: MCQ with Answer and Explanation

The genetic disease caused by the absence of an enzyme that breaks down phenylalanine is:
A. Albinism
B. Sickle cell anemia
C. Phenylketonuria
D. Cystic fibrosis
Answer: Option C
Solution (By JKSSB Mock Tests)
Phenylketonuria (PKU) is an autosomal recessive disorder due to deficiency of phenylalanine hydroxylase, leading to accumulation of phenylalanine, causing mental retardation if untreated. Albinism is tyrosinase deficiency, sickle cell HbS mutation, cystic fibrosis CFTR defect.

Discuss this Question (0)

No comments yet. Be the first to start the discussion!

Practice More Biology Questions

Question #1
Which of the following statements about the plant stem is correct?
A. It is the main site of photosynthesis in most plants.
B. It bears leaves, flowers, and fruits.
C. It is usually positively phototropic.
D. It grows downward into the soil.

Correct Answer: Option B


Explanation:
Stem bears leaves and reproductive structures. It is positively phototropic (grows towards light). Leaves are the main photosynthetic organs. Roots grow downward.

This question belongs to: Science Biology
Question #2
Which of the following is the primary target organ for the hormone insulin?
A. Kidney
B. Brain
C. Liver
D. Heart

Correct Answer: Option C


Explanation:
Insulin acts primarily on liver, muscle, and adipose tissue. The liver is a key target where insulin promotes glycogenesis (glucose to glycogen), glycolysis, and lipogenesis, and inhibits gluconeogenesis, lowering blood glucose. Muscle and adipose tissue also respond. Brain takes up glucose independently of insulin via GLUT1 transporters. Thus liver is a principal target.

This question belongs to: Science Biology
Question #3
The salivary gland located below the tongue is the:
A. Parotid gland
B. Lacrimal gland
C. Submandibular gland
D. Sublingual gland

Correct Answer: Option D


Explanation:
The sublingual glands are the smallest of the three paired salivary glands, located under the tongue. The parotid is near the ear, submandibular under the jaw.

This question belongs to: Science Biology