AmB 361 2025_Phoenix

What is culture media?

A mixture of materials designed to support the metabolic processes of microorganisms, providing all nutrients needed for growth in vitro.

What are chemoheterotrophs?

Microorganisms that require organic compounds for carbon and energy, commonly grown in laboratory conditions.

Why is carbon essential in culture media?

Carbon is essential for the synthesis of all organic compounds, including carbohydrates, proteins, lipids, and nucleic acids.

How do heterotrophs obtain nitrogen?

Heterotrophs must have nitrogen provided in culture media, often supplied by protein or protein breakdown products.

What role do minerals play in culture media?

Minerals like sulfur, phosphorus, and iron are essential for the synthesis of important organic compounds and enzyme activity.

What is the function of buffers in culture media?

Buffers resist pH change when the acidic or alkaline waste products from microorganisms are released into media.

Define a defined or synthetic medium.

A medium with known quantities of all ingredients such as CO2 for carbon and ammonia or nitrate for nitrogen.

What is selective media?

Media used to grow only selected microorganisms while inhibiting the growth of others.

What is differential media?

Indicator media used to distinguish one microorganism type from another on the same medium based on biochemical characteristics.

What is the purpose of transport media?

Used when specimens cannot be cultured immediately after collection.

What is the hallmark of enriched media?

Enriched media are made by adding substances like blood or serum to promote the growth of fastidious organisms.

What are the three types of culture media based on consistency?

Liquid medium (broth), semi-solid medium, and solid medium.

What is a streak plate culture?

A technique of isolating bacteria by streaking a bacterial sample across an agar plate to isolate individual cells.

How does the pour plate technique work?

Involves diluting a sample in agar tubes, pouring it into petri dishes and allowing colonies to grow.

What is maintenance of bacterial culture?

Storing bacterial cultures alive for future use, involving various methods like periodic transfer, storage in mineral oil, and lyophilization.

What is the dry weight method?

An indirect method for measuring bacterial growth by weighing dried cells after filtering a known volume of culture.

What is the turbidimetric method used for?

Measuring bacterial growth by assessing the turbidity or scattering of light in a culture.

What is mutation in the context of strain improvement?

A sudden and heritable change in the traits of an organism, which can be spontaneous or induced.

Explain recombinant DNA technology.

A genetic engineering process involving isolation, cloning, and expression of desired genes in suitable host organisms.

What is transduction?

The transfer of bacterial DNA from one cell to another via bacteriophage.

What is metabolic engineering?

The rational design or redesign of an organism's metabolic pathways to enhance product yields and reduce by-products.