Microbio Chapter 6

Phototroph

Use light as an energy source

Chemotrophs

Use potential energy stored in chemical compounds as energy source

Chemo lithotroph

Needs inorganic chemicals

Chemo organotrophs

Use organic compounds for energy

Autotroph

Makes own carbon compounds starting with CO2, carbon fixation

Heterotrophs

Obtain carbon compounds from other organisms

Methanotrophy

Uses methane to create CO2

Methanogenesis

Uses CO2 and hydrogen to produce methane, anerobic resperiation

Nitrogen

Helps in making amino acids (protiens) and nucleic acids (DNA/RNA)

Denitrification

The process by which nitrogen oxides are reduced to nitrogen gas, often in anaerobic conditions. Ex: NO3- to N2

Nitrogen Fixation

A microbial process that converts atmospheric nitrogen (N2) into ammonia (NH3), making nitrogen available for use by plants and other organisms.

Assimilation

The process by which plants and microorganisms uptake and incorporate ammonia or nitrate into organic compounds, such as amino acids and proteins.

Decomposition

The process by which organic matter is broken down into simpler inorganic substances, recycling nutrients back into the ecosystem.

Nitrification

A microbial process that converts ammonium (NH4) into and then into nitrates (NO3-), making nitrogen accessible for plant uptake.

Nitrogenase

The enzyme that catalyzes Nitrogen fixation, sensitive O2

Strict anaerobe

Must have no oxygen to grow only grows on bottom of the medium in a test tube, not enzymes to detoxify ROS.

Strict Aerobe

Must have O2 to grow, only grows on top of the medium in a test tube. Has SOD and catalase

Microaerophile

Prefers lower O2 levels, will grow in middle of the medium in a test tube. Low levels of SOD and catalase

Facultative Anaerobe

Prefers O2, but can grow without, have microbes scattered through test tube, but more clustered toward the top. Has SOD and catalase

Aerotolerant Anaerobe

Doesn’t use O2, but tolerates it, so it can grow anywhere in tube, scatter evenly throughout, obligate fermenters. Has only SOD

Reactive Oxygen Species (ROS)

Produced as byproducts of aerobic metabolism. Damages DNA, proteins, membrane, etc…

Superoxide Dismutase (SOD) and Catalase

Enzymes that break down ROS, SOD protects and catalase allows for utilization

Auxotrophy

When a microbe cannot synthesize an essential nutrient, it must be added to culture media for organism to grow and divide, aka Growth Factors

Complex Media

A media filled with a large variety of organic matter that is not fully known

Chemically Defined Media

A media where all the chemical components are known

Hyperthermophile

Prefers temps above 80C, thrives in extreme heat environments such as hydrothermal vents.

Thermophile

Organism that thrives at moderately high temperatures, typically between 50C and 80C.

Mesophile

Grows best at moderate temperatures, typically between 20-45°C, often found in humans and other mammals

Psychrophile

Organism that thrives at low temperatures, typically below 15°C, often found in polar regions and deep ocean environments.

Alkaliphile

Organism that thrives in alkaline conditions, typically at a pH above 9, often found in soda lakes and alkaline soils. Has extra pumps to pull H into cell so that inside remains neutral PH

Neutralophile

Organism that grows best in neutral pH conditions, typically around pH 6-8, commonly found in soil and human microbiota.

Acidophile

Organism that thrives in acidic conditions, typically at a pH below 5.5, often found in environments like acidic hot springs and sulfuric pools. Has extra H pumps to push H out of cell so that insde remains neutral PH

Halophile

Organism that thrives in high salt concentrations, commonly found in salt lakes and coastal regions. Has extra Na pumps to avoid plasmolysis

Barophile

An organism that thrives under high pressure conditions, typically found in deep-sea environments and deep subsurface habitats.

Barotolerant

Organism that can tolerate high pressure but does not require it for growth, often found in environments with varying pressure levels.

Binary Fission

A method of asexual reproduction in which a single organism divides into two identical daughter cells, exponential growth

Lag Phase

Bacteria preparing for massive growth, and adjusting to new environment

Log Phase

Shortest generation time, fastest growing period, makes an exponential line

Stationary Phase

Cells stop growing and shut down growth machinery while turning on stress response to help retain viability

Death Phase

Cells begin to die at exponential rate

Primary Metabolites

Produced during very active growth and metabolism, such as amino acids, nucleotides, and organic acids. Occurs in Log Phase

Secondary Metabolites

Not essential for rapid growth, often made for defense or survival, occur in stationary phase, and include antibiotics and toxins.

Biofilm

Polymer encased community of microbes (different species) that adhere to surfaces, providing protection and promoting nutrient exchange, secrete Extracellular Polymeric Substances (EPS), ex: plaque, large cause for infections, helps microbes resist immune system

Quorum Sensing

is a regulatory system that enables bacteria to communicate and coordinate behavior based on population density, often by producing signaling molecules.

Pellicle

A thin layer or film of microorganisms that forms on the surface of a liquid culture, often seen in biofilms or floating microbial communities.

Endospore

Structures that are very resistant to many conditions, vegetative= happily growing, cells resting state, formed from sporulation

Germination

is the process by which an endospore returns to a vegetative state after favorable conditions are restored, leading to growth and replication.

Dipicolinic Acid

Produced in later stages of sporulation, stabilizes and protects DNA of spore, while also contributing to the heat resistance of the endospore.

Food Spoilage

When microbial changes and metabolism affect food chemistry, making unfit for consumption

Food contamination

Presence of pathogens or harmful microbes in food, could lead to food poisoning

Bactericidal

Agents or methods have lethal effect and kill microbes

Bacteriostatic

Methods that slow or stop metabolism but not lethal, inhibit bacterial growth

Preservation

Delay spoilage of food by inhibiting microbial growth or activity.

Desiccation

Dehydration, removes water to prevent microbial growth, type of bacteriostatic, cells in state of plasmolysis

Controlled atmospheres

Gaseous environments adjusted to inhibit microbial growth, such as refrigeration, or freezing

Pasteurization

Heat treatment process that kills or inactivates pathogens in foods and beverages, extending shelf life without compromising quality, bactericidal, but does not sterilize

Canning or Autoclave

Bactericidal, preservation method that involves sealing food in airtight containers and heating to destroy harmful microorganisms, uses high tempetures

Food Irradiation

Damages cells and DNA, good for heat and moisture sensitive items, using ionizing radiation, bactericidal and can sterilize