TN State Board 12th Microbiology Question Paper 2025

Nano particles are usually defined as particles with size of 100 nm or less, so the correct answer is (d) 100 nm or less. Options (a) and (c) are too large for the nano range, and (b) is too small and does not represent the full nano-scale range.

Scanning Electron Microscope (SEM) helps us obtain a 3-D picture of the specimen, so the correct answer is (d) SEM. A compound microscope and a simple microscope give only a 2-D view, while TEM provides internal details of thin specimens but not a 3-D surface image.

Quaternary ammonium salts are used as preservatives in ophthalmic solutions, so the correct answer is (d). Phenol, alcohol, and aldehydes are used mainly as disinfectants or preservatives in other preparations, not typically for ophthalmic solutions.

Copper sulphate is used in lakes and swimming pools to retard the growth of algae, so the correct answer is (b). Formaldehyde is a disinfectant, alcohol is used as an antiseptic/disinfectant, and silver nitrate is used for specific antimicrobial purposes, not for controlling algae in water bodies.

One molecule of glucose, when oxidized in glycolysis, produces 2 molecules of pyruvic acid, so the correct answer is (d) 2. The other options are incorrect because glucose does not yield 1, 3, or 4 pyruvate molecules in this process.