Q. What condition results from a deficiency in the enzyme ornithine transcarbamylase?
-
A.
Phenylketonuria
-
B.
Urea cycle disorder
-
C.
Maple syrup urine disease
-
D.
Homocystinuria
Solution
A deficiency in ornithine transcarbamylase leads to a urea cycle disorder, causing hyperammonemia.
Correct Answer:
B
— Urea cycle disorder
Learn More →
Q. What is the end product of the urea cycle?
-
A.
Uric acid
-
B.
Ammonia
-
C.
Urea
-
D.
Creatinine
Solution
The end product of the urea cycle is urea, which is excreted in urine.
Correct Answer:
C
— Urea
Learn More →
Q. What is the primary organ responsible for nitrogen metabolism in the human body?
-
A.
Liver
-
B.
Kidney
-
C.
Lungs
-
D.
Spleen
Solution
The liver is the primary organ responsible for nitrogen metabolism, including the urea cycle.
Correct Answer:
A
— Liver
Learn More →
Q. What is the primary source of nitrogen for the synthesis of non-essential amino acids?
-
A.
Dietary proteins
-
B.
Ammonia
-
C.
Urea
-
D.
Nucleic acids
Solution
Ammonia is the primary source of nitrogen for the synthesis of non-essential amino acids through transamination.
Correct Answer:
B
— Ammonia
Learn More →
Q. What is the role of glutamine in nitrogen metabolism?
-
A.
Energy source
-
B.
Nitrogen donor
-
C.
Carbon source
-
D.
Hormone precursor
Solution
Glutamine acts as a nitrogen donor in various biosynthetic reactions, including nucleotide synthesis.
Correct Answer:
B
— Nitrogen donor
Learn More →
Q. Which amino acid is considered the main nitrogen donor in transamination reactions?
-
A.
Glutamate
-
B.
Alanine
-
C.
Aspartate
-
D.
Serine
Solution
Glutamate is the main nitrogen donor in transamination reactions, facilitating amino acid synthesis.
Correct Answer:
A
— Glutamate
Learn More →
Q. Which enzyme catalyzes the first step of the urea cycle?
-
A.
Carbamoyl phosphate synthetase
-
B.
Ornithine transcarbamylase
-
C.
Arginase
-
D.
Argininosuccinate synthetase
Solution
Carbamoyl phosphate synthetase catalyzes the first step of the urea cycle, converting ammonia and bicarbonate to carbamoyl phosphate.
Correct Answer:
A
— Carbamoyl phosphate synthetase
Learn More →
Q. Which metabolic pathway is primarily responsible for the detoxification of ammonia in the liver?
-
A.
Glycolysis
-
B.
Urea cycle
-
C.
Krebs cycle
-
D.
Fatty acid oxidation
Solution
The urea cycle is primarily responsible for the detoxification of ammonia in the liver, converting it to urea.
Correct Answer:
B
— Urea cycle
Learn More →
Q. Which of the following is a key intermediate in the urea cycle?
-
A.
Fumarate
-
B.
Citrulline
-
C.
Aspartate
-
D.
Glutamine
Solution
Citrulline is a key intermediate in the urea cycle, formed from carbamoyl phosphate and ornithine.
Correct Answer:
B
— Citrulline
Learn More →
Q. Which vitamin is essential for the proper functioning of the enzyme that converts homocysteine to methionine?
-
A.
Vitamin B6
-
B.
Vitamin B12
-
C.
Vitamin C
-
D.
Folate
Solution
Vitamin B12 is essential for the enzyme methionine synthase, which converts homocysteine to methionine.
Correct Answer:
B
— Vitamin B12
Learn More →
Showing 1 to 10 of 10 (1 Pages)
