Question

Nitrogenous and metabolic wastes are stored in the
(i) amniotic bag (ii) allantois (iii) yolk sac
(iv) exocoel
doar cells are characterist:​

Answer 1

Explanation:

devolapment within the cleidoic egg of birds and reptiles presents the embryo with the problem of accumulation of wastes from nitrogen metabolism. Ammonia derived from protein catabolism is converted into the less toxic product urea or relatively insoluble uric acid. The pattern of nitrogen excretion of the green iguana, Iguana iguana, was determined during embryonic development using samples from allantoic fluid and from the whole homogenized egg, and in hatchlings and adults using samples of blood plasma. Urea was the major excretory product over the course of embryonic development. It was found in higher concentrations in the allantoic sac, suggesting that there is a mechanism present on the allantoic membrane enabling the concentration of urea. The newly hatched iguana still produced urea while adults produced uric acid. The time course of this shift in the type of nitrogen waste was not determined but the change is likely to be related to the water relations associated with the terrestrial habit of the adult. The green iguana produces parchment-shelled eggs that double in mass during incubation due to water absorption; the eggs also accumulate 0.02 mM of urea, representing 82% of the total measured nitrogenous residues that accumulate inside the allantois. The increase in egg mass and urea concentration became significant after 55 days of incubation then were unchanged until hatching.

Answer 2

Answer:

Nitrogenous and metabolic wastes are stored in the allantois.             

Explanation:

• As an adaptation to terrestrial life, the embryos of reptiles, birds, and mammals develop within a fluid-filled amniotic membrane, or amnion.
• The amniotic membrane and several other membranes form from embryonic cells, but they are located outside of the body of the embryo which is why they are known as extraembryonic membranes.

• The extraembryonic membranes include the amnion, chorion, yolk sac, and allantois.

• In birds, the amnion and chorion surround the embryo. The amnion is the inner membrane that surrounds it. The embryo is suspended in amniotic fluid. Hence option (i) is incorrect.

• The chorion is located next to the eggshell and is separated from the other membranes by a cavity-the extraembryonic coelom (exocoel). Hence option (iv) is incorrect.

• The yolk sac plays a critical role in the nutrition of bird and reptile embryos; it is also present in mammals, although it does not nourish the embryo. Hence option (iii) is incorrect.

• The allantois is the extraembryonic film that stores the metabolic wastes of the incipient organism. The allantois serves to store the uric acid excreted in the urine of birds.
• The nitrogenous wastes excreted from the undeveloped organism are passed into cloaca by the Wolffian conduits and afterwards into the allantois.
• It additionally helps in the vaporous trade during the embryonic stage.

Therefore option (ii) allantois is the correct answer.

#SPJ3