What is true of urea biosynthesis?

(1) Uric acid is starting point

(2) Urea is synthesised in lysosomes

(3) Urea cycle enzymes are located inside mitochondria

(4) Urea is synthesised in kidney

Assertion   :       Ammonia should be eliminated from the body as rapidly as it is formed.

Reason      :       Ammonia is insoluble in water.

Assertion   :       Urinary bladder and ureters are lined by transitional epithelium.

Reason      :       Ureters carry the urine to urinary bladder where it is stored temporarily.

Assertion   :       In vertebrates, the liver is also referred as an accessory excretory organ.

Reason      :       Liver helps kidneys in the secretion of urine.
1.  Both A & R are true and the R is the correct explanation of the A.
2.  Both A & R are true but the R is not the correct explanation of the A.
3.  A is true statement but R is false.
4.  Both A and R are false statements.

Assertion   :       Sharks are said to be ammonotelic animals.

Reason      :       Sharks can retain considerable amounts of ammonia in their blood.

Assertion   :       Aquatic mammals like whales and seals are said to be ureotelic animals.

Reason      :       It is because of the fact that their main nitrogenous waste product is urea.

Assertion   :       Death ensues if waste products are not removed from the body.

Reason      :       Excretory system removes the nitrogenous waste products from the body.

Assertion   :       Camel can go without water for long periods.

Reason      :       Camels stores water in the pouches of their rumen and fat in their hump.

Assertion   :       Renal threshold of glucose is said to be 180 mg per 100 ml.

Reason      :       Glucose starts appearing in the urine when its blood level exceed 180 mg per 100 ml of blood.

Assertion   :       Earthworms excrete both ammonia and urea.

Reason      :       Excretion in earthworm depends on the environment.