The 'Central Dogma' of molecular biology, which describes the flow of genetic information, was proposed by: MCQ with Answer and Explanation

Explanation:
The Sinoatrial (SA) node, the natural pacemaker of the heart, is a small, specialized mass of autorhythmic cardiac muscle cells located in the upper wall of the right atrium, just below the opening of the superior vena cava. It spontaneously generates electrical impulses at a regular rate, which spread through the atrial myocardium, causing the atria to contract and push blood into the ventricles. The impulse then reaches the AV node.

Explanation:
The liver is the primary organ for glycogenesis (storing glucose as glycogen) and glycogenolysis, maintaining blood glucose levels. Muscles store glycogen for local use. Pancreas regulates via hormones, kidneys excrete excess glucose.

Explanation:
Alexander Fleming accidentally discovered penicillin in 1928 when a mold (Penicillium) inhibited bacterial growth on a plate. Florey and Chain purified it.