Bacterial Growth and Nutrition

What is binary fission?

Division of a bacterial cell into two identical daughter cells.

What does generation time refer to in microbial growth?

The time required for a cell population to double.

What happens during the lag phase of bacterial growth?

Interval between when a culture is inoculated and when growth begins, initially at low density.

What defines the exponential phase in bacterial growth?

Cells are in a healthy state and doubling at a constant rate; division occurs faster than death.

What occurs in the stationary phase of bacterial growth?

Growth rate is zero; the population size remains constant due to nutrient depletion or waste accumulation.

What do macronutrients include?

Substances like carbohydrates, proteins, lipids, carbon, nitrogen, sulfur, and phosphorus.

What is the importance of siderophores in bacteria?

They are iron-chelating compounds that help bacteria acquire iron from the environment.

How do psychrotolerant microorganisms differ from psychrophiles?

Psychrotolerant organisms can grow at 0°C but have optimal growth between 20°C to 40°C, while psychrophiles thrive at lower temperatures.

What characterizes halophilic microorganisms?

They require high salt concentrations for optimal growth and often synthesize or concentrate organic solutes for osmotic balance.

What technique is used to measure microbial growth using turbidity?

A spectrophotometer measures the cloudiness of a culture, which is proportional to cell number.

What is the role of plasmids in bacterial cells?

Plasmids are small, circular pieces of DNA that can replicate independently and often carry genes that confer advantageous traits.

What is quorum sensing in bacteria?

A communication process that enables bacteria to assess their population density and coordinate behavior in response to the density.

What are biofilms in microbial growth?

Biofilms are structured communities of microorganisms adhered to surfaces, encapsulated in a protective extracellular matrix.

How do temperature and pH affect microbial growth?

Microbial growth rates are strongly influenced by temperature and pH, with each species having specific optimal conditions.

What are anaerobic bacteria?

Bacteria that do not require oxygen for growth and may even be poisoned by it.

What is a pathogen?

A microorganism that can cause disease in a host organism.

What is the significance of microbial fermentation?

Fermentation is an anaerobic process that converts sugars into acids, gases, or alcohol, playing a role in food production and energy metabolism.

What is the importance of nutrient agar?

Nutrient agar is a growth medium that supports the growth of a wide range of non-fibrous organisms by providing essential nutrients.

What is selective media?

Selective media are types of agar that favor the growth of particular microorganisms while inhibiting others.

What is the difference between prokaryotic and eukaryotic cells?

Prokaryotic cells are generally smaller, simpler, and lack a nucleus, while eukaryotic cells are larger, more complex, and contain a nucleus and organelles.