This set of Human Physiology Multiple Choice Questions & Answers (MCQs) focuses on “Excretory System in Man”.
1. A condition in which body’s internal environment remains nearly constant is called as _________
a) Homeostasis
b) Hematoma
c) Hemostasis
d) Hemopoeisis
View Answer
Explanation: Homeostasis can be defined as the stable condition of an organism and of its internal environment or as the maintenance or regulation of the stable condition.
2. The presence of arginase confirms that ___________
a) Urea cycle is operating
b) Arginine is being converted to ornithine
c) Urea cycle maybe operating
d) Arginine is being converted to citrulline
View Answer
Explanation: Arginine is an alpha amino acid. Arginase is a manganese containing an enzyme, it is the final enzyme of urea cycle. Arginine and water forms ornithine and urea.
3. Removal of amino group to transform into keto acid is called ___________
a) Transamination
b) Deamination
c) Ammonofication
d) Amination
View Answer
Explanation: Deamination is the removal of an amino group from a molecule. In human deamination takes place in liver however glutamate is deaminated in kidneys.
4. In the ornithine cycle which of the following waste is removed from the blood?
a) Urea and urine
b) Carbon dioxide and urea
c) Ammonia and carbon dioxide
d) Ammonia and urea
View Answer
Explanation: Urea cycle is also known as Ornithine cycle. It converts highly toxic ammonia to urea for excretion. It takes place in the Liver.
5. The function of flame cell is ____________
a) Excretion
b) Digestion
c) Respiration
d) Reproduction
View Answer
Explanation: Flame cell is a specialized excretory cell found in freshwater invertebrates. Flame cells function like kidney removing waste materials.
6. Urea is directly produced in mammals from ___________
a) Breakdown of arginine
b) Oxidative deamination of proteins
c) Breakdown of ornithine
d) Ammonia released by oxidative deamination
View Answer
Explanation: Urea is directly produced in mammals from ammonia released by oxidative deamination. During oxidative deamination amino acid is converted into corresponding keto acid by removal of amine functional group as ammonia and amine functional group.
7. Which blood vessel carries the least amount of urea?
a) Pulmonary vein
b) Renal artery
c) Renal vein
d) Hepatic portal vein
View Answer
Explanation: Renal veins are veins that drain the kidney. They connect the kidney to the inferior vena cava. They carry blood filtered by the kidney. Renal vein carries the least amount of urea.
8. The amino acid that acts as carrier of ammonia from skeletal muscle to the liver is ____________
a) Alanine
b) Glutamine
c) Methionine
d) Arginine
View Answer
Explanation: Glutamine is an alpha amino acid used for the biosynthesis of protein. It carries ammonia from skeletal muscle to the liver.
9. Primary excretory organs are kidneys while accessory excretory organs urinary bladder.
a) True
b) False
View Answer
Explanation: Primary excretory organs are kidneys while the accessory excretory organs are skin lungs and liver.
10. Which of the following facilitates reabsorption of water by nephron?
a) Medulla
b) Cortex
c) Pelvis
d) Loop of nephron
View Answer
Explanation: Nephron is a functional and structural unit of kidney. Loop of nephron facilitates reabsorption of water.
Sanfoundry Global Education & Learning Series – Human Anatomy and Physiology.
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