TN State Board 12th Microbiology Question Paper 2024

Frits Zernike invented the Phase Contrast microscope in the 1930s, for which he received the Nobel Prize in Physics in 1953. George Stokes is known for fluorescence, Robert Koch for the germ theory of disease, and Alexander Fleming for the discovery of penicillin.

In prokaryotes, aerobic respiration of one glucose molecule yields a theoretical maximum of 38 ATP molecules. This occurs because, unlike in eukaryotes, there is no transport cost for moving NADH produced in glycolysis into the mitochondria, allowing for a higher net yield.

Dolly the sheep was the first mammal to be successfully cloned from an adult somatic cell using the technique of nuclear transfer in 1996.

Water activity ($a_w$) is a measure of the available moisture for microbial growth. Most bacteria require an $a_w$ of at least 0.90, but the general minimum value for the growth of most common spoilage microorganisms in food is considered to be around 0.86.

Phenols act by denaturing proteins and disrupting cell membranes; they possess poor penetrating power compared to gases like Ethylene oxide or Beta-propiolactone, which are used as gaseous sterilants due to their high penetrating capability.