Consider the following statements about the heart: 1. The SA node is the natural pacemaker. 2. The AV node delays the impulse before it passes to ventricles. 3. The Purkinje fibers conduct impulses through the ventricular walls. Which of the above is/are correct? MCQ with Answer and Explanation

Explanation:
Pinocytosis (cell drinking) is a type of endocytosis where the cell membrane forms small vesicles to engulf extracellular fluid and dissolved substances. Phagocytosis is for large particles, exocytosis is export, endocytosis is general term.

Explanation:
Albinism is a genetic disorder due to a defect in tyrosinase enzyme, leading to little or no melanin production, affecting skin, hair, and eye color. Vitiligo is patchy loss of melanocytes, jaundice is yellowing from bilirubin, erythema is redness. Albinism results in extreme sensitivity to sunlight.

Explanation:
Ammonia (NH₃) is highly toxic and requires large volumes of water for its excretion; hence it is produced by aquatic animals. Urea is less toxic, uric acid least toxic and water-insoluble. Creatinine is a minor waste. Ammonia is converted to urea in the liver via the urea cycle in ureotelic organisms.