General Microbiology

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Questions and Answers

Enlist the applied field of microbiology. Comment on food microbiology.

Applied fields of microbiology include medical, industrial, agricultural, and environmental microbiology. Food microbiology involves the study of microorganisms that cause food spoilage, foodborne illness, and fermentation.

Differentiate between phototrophs and chemotrophs.

Phototrophs obtain energy from sunlight through photosynthesis, whereas chemotrophs obtain energy from chemical compounds through oxidation-reduction reactions.

Enlist the methods of maintenance and preservation of pure cultures. Explain in brief about cryopreservation.

Methods include serial subculturing, refrigeration, freezing, drying, and cryopreservation. Cryopreservation involves storing cultures at ultra-low temperatures (e.g., -80°C or -196°C) to preserve their viability for extended periods.

Draw a labeled diagram of a typical bacterial cell.

A typical bacterial cell diagram should include labels for the cell wall, cell membrane, cytoplasm, nucleoid (DNA), ribosomes, and any external structures such as flagella or pili. Signup and view all the answers

What is the mode of action of antimicrobial agents on microorganisms?

Antimicrobial agents can disrupt cell walls, inhibit protein synthesis, interfere with nucleic acid replication, or disrupt cell membrane function. Signup and view all the answers

Comment on bacteriological media.

Bacteriological media are nutrient-rich substances used to grow and cultivate bacteria in the laboratory. Different types of media exist, including broth, agar, selective, and differential media, each serving specific purposes. Signup and view all the answers

What do you mean by nutrient transport phenomenon?

Nutrient transport refers to the mechanisms by which cells acquire essential nutrients from their environment. This can occur through passive diffusion, facilitated diffusion, active transport, or group translocation. Signup and view all the answers

Name any three physical agents that are used for controlling microorganisms. Enlist the factor which influences the antimicrobial action of physical agents.

Heat, radiation, and filtration are physical agents used for controlling microorganisms. Factors influencing their antimicrobial action include the intensity/dose, exposure time, and type of microorganism. Signup and view all the answers

Draw the bacterial growth curve and name the various phases.

The bacterial growth curve includes the lag phase, exponential (log) phase, stationary phase, and death phase. Signup and view all the answers

Enlist the differential staining technique. Why cells are stained.

Differential staining techniques include Gram staining, acid-fast staining, and endospore staining. Cells are stained to enhance contrast, differentiate between cell types, and visualize cellular structures under a microscope. Signup and view all the answers

Define sterilization.

Sterilization is the process of completely eliminating all forms of microbial life, including bacteria, fungi, viruses, and spores, from a surface, object, or environment. Signup and view all the answers

______ is a filamentous appendage found on bacterial cells and helps in adherence to host cells.

Fimbriae Signup and view all the answers

What is mutation?

Mutation is a change in the nucleotide sequence of an organism's genome, which may result in altered traits or characteristics. Signup and view all the answers

Define antibiotics.

Antibiotics are substances produced by microorganisms or synthetically manufactured that inhibit the growth of or kill bacteria. Signup and view all the answers

Name any two Gram-positive bacteria.

Examples of Gram-positive bacteria include Staphylococcus aureus and Bacillus subtilis. Signup and view all the answers

PDA stands for...

Potato Dextrose Agar Signup and view all the answers

Turbidity measurements employ a variety of instruments to determine the amount of [blank] scattered by a suspension of cells.

light Signup and view all the answers

______ are bacteria which grows best at temperature above 45°C.

Thermophiles Signup and view all the answers

What is mean by halophiles.

Halophiles are microorganisms that thrive in high salt concentrations. Signup and view all the answers

The most common means of bacterial reproduction is...

Binary fission Signup and view all the answers

What do you mean by microbiology?

Microbiology is the study of microorganisms, including bacteria, fungi, viruses, protozoa, and algae. Signup and view all the answers

What is temperature requirement for sterilization by autoclave.

Typically, sterilization by autoclave requires a temperature of 121°C (250°F) for 15-20 minutes at 15 psi. Signup and view all the answers

Why moist heat has more effective than dry heat for killing of microorganism.

Moist heat is more effective because it denatures proteins and disrupts cell membranes more efficiently than dry heat. Moist heat also penetrates materials more readily. Signup and view all the answers

Expand the term MPN.

Most Probable Number Signup and view all the answers

Flashcards

Microbiology

The study of microorganisms, including bacteria, viruses, fungi, and protozoa.

Food Microbiology

A branch of microbiology that focuses on the microorganisms that affect food, both beneficial and detrimental.