Microbial Growth, Control, and Classification: Bacteria and Archaea Overview

What is the take-home message of the MARS rover?

The specific take-home message is not provided in the notes.

What physical and chemical factors affect bacterial growth?

include temperature, pH, and nutrient availability.

How are bacteria categorized based on temperature?

psychrophiles (cold), mesophiles (moderate), and thermophiles (heat).

Which category of bacteria is commonly found in food in the refrigerator?

Psychrophiles

Which category of bacteria is likely to cause human disease?

Mesophiles

Which biomolecules contain Carbon?

Carbohydrates, lipids, proteins, and nucleic acids

Which biomolecules contain Nitrogen, Phosphorus, and Sulfur?

Proteins contain Nitrogen; nucleic acids contain Phosphorus; amino acids contain Sulfur.

What are the different phases of bacterial growth?

lag, exponential, stationary, and death.

What occurs during the lag phase of bacterial growth?

Bacteria adapt to their environment and prepare for growth.

What happens during the exponential phase of bacterial growth?

Bacteria divide at a constant and rapid rate.

What is sterilization?

the process of eliminating all forms of microbial life.

Why is it not always practical to achieve sterilization?

It can be costly, time-consuming, and may not be necessary in all situations.

What are the physical methods of controlling microbial growth?

dry heat, moist heat, filtration, and radiation.

What are the factors affecting disinfection efficiency?

concentration of disinfectant, contact time, and presence of organic matter.

What chemical methods are used to kill bacteria?

phenolics, biguanides, essential oils, halogens, alcohols, metals, surfactants, and preservatives.

What types of bacteria are found in the phylum Pseudomonadota?

Pseudomonas, Salmonella, Vibrio, Yersinia, Legionella

What is an example of the phylum Campylobacterota?

Campylobacter jejuni

What are the similarities and differences among the phyla cyanobacterota, chlorobi, and chloroflexi?

all photosynthetic but differ in their pigments and metabolic pathways.

What are the properties of the phylum Bacteroidota?

are anaerobic, Gram-negative bacteria often found in the gut.

What are the characteristics of Gram-positive phyla with low G+C?

Includes Bacillota, which are typically spore-forming

What are the characteristics of Gram-positive phyla with high G+C?

Includes Actinomycetota, known for their filamentous growth and antibiotic production.

What are the types of Archaea?

methanogens, halophiles, and thermophiles.

Disinfection

reduces the number of pathogenic microorganisms to levels that no longer pose a health threat

Asepsis

preventing infections by eliminating or destroying microorganisms before they can enter the body