BT102 Midterm Past Papers Updated 2022

Q1. Why Catalase Test is Used ?

The catalase test is a particularly important test used to determine whether a gram-positive cocci is a staphylococci or a streptococci. Catalase is an enzyme that converts hydrogen peroxide to water and oxygen gas. ... If bubbles appear (due to the production of oxygen gas) the bacteria are catalase positive.

2)Define Osmotic lysis

Cytolysis, or osmotic lysis, occurs when a cell bursts due to an osmotic imbalance that has caused excess water to diffuse into the cell. ... The presence of a cell wall prevents the membrane from bursting, so cytolysis only occurs in animal and protozoa cells which do not have cell walls.

3)Define Plasmolysis

Plasmolysis is a typical response of plant cells exposed to hyperosmotic stress. The loss of turgor causes the violent detachment of the living protoplast from the cell wall. The plasmolytic process is mainly driven by the vacuole

4)Osmotic Pressure

Osmotic pressure is defined as the pressure that must be applied to the solution side to stop fluid movement when a semipermeable membrane separates a solution from pure water.

Q5. Advantages of Solid Medium?

• Pure culture is easy to obtain by streaking the organisms
• Colony characters can be studied

.Bacteria may be identified by studying the colony character, .Mixed bacteria can be separated. Solid media is used for the isolation of bacteria as pure culture.

Q6. Names of 5 Kingdoms ?

Five Kingdom Classification of Organisms ➢ Monera: Bacteria and Archea ➢ Protista ➢ Fungi ➢ Plantae ➢ Animalia

Q7. Genetics, Gene, Genotype , Chromosome, Phenotype, Genome??

➢ Genetics: The study of what genes are, how they carry information, how information is expressed, and how genes are replicated ➢ Gene: A segment of DNA that encodes a functional product, usually a protein ➢ Chromosome: Structure containing DNA that physically carries hereditary information; the chromosomes contain the genes ➢ Genome: All the genetic information in a cell ➢ Genomics: The molecular study of genomes ➢ Genotype: The genes of an organism ➢ Phenotype: Expression of the genes

Q8. Defined and Complex Media??

Classification of Media

• Chemical composition

– Defined (synthetic)

If we know the organism

– Complex

When organism is not known or is fastidious

9)Physical Method of Bacterial Control

Physical methods for control of microbial population