Exercise 11: Temperature Requirements of Bacteria Flashcards

Flashcards covering temperature classifications, ranges, cardinal temperatures, specific bacterial examples, and cellular effects on enzymes and lipids.

Minimum Growth Temperature

The lowest temperature at which a specific organism will grow and reproduce.

Optimum Growth Temperature

The temperature at which a specific organism exhibits maximum growth and reproduction.

Maximum Growth Temperature

The highest temperature at which a specific organism will grow and reproduce.

Bacterial Growth Temperature Range

The overall temperature span across which bacteria are capable of growth, ranging from $-5^\bullet\text{C}$ to $80^\bullet\text{C}$.

Cardinal Temperatures

The three critical growth temperature points for bacteria: minimum, optimum, and maximum growth temperatures.

Psychrophile

A cold-loving microorganism that grows at temperatures ranging from $-5^\bullet\text{C}$ to $20^\bullet\text{C}$.

Psychrotroph

A microorganism that grows at temperatures below $10^\bullet\text{C}$, but also grows in the mesophile range.

Mesophile

A microorganism that grows at moderate temperatures ranging from $20^\bullet\text{C}$ to $45^\bullet\text{C}$.

Thermophile

A heat-loving microorganism that grows at temperatures ranging from $45^\bullet\text{C}$ to $80^\bullet\text{C}$.

Hyperthermophile

A microorganism that grows at extremely high temperatures greater than $80^\bullet\text{C}$.

Listeria monocytogenes

A psychrophilic bacterium that grows at temperatures ranging from $-5^\bullet\text{C}$ to $20^\bullet\text{C}$.

Pseudomonas fluorescens

A psychrotrophic bacterium that grows below $10^\bullet\text{C}$ but also grows in the mesophile range.

Escherichia coli

A mesophilic bacterium that grows in the temperature range of $20^\bullet\text{C}$ to $45^\bullet\text{C}$.

Serratia marcescens

A mesophilic bacterium that grows in the temperature range of $20^\bullet\text{C}$ to $45^\bullet\text{C}$.

Micrococcus luteus

A mesophilic bacterium that grows in the temperature range of $20^\bullet\text{C}$ to $45^\bullet\text{C}$.

Bacillus stearothermophilus

A thermophilic bacterium that grows in the temperature range of $45^\bullet\text{C}$ to $80^\bullet\text{C}$.

Archaea (Temperature Classification)

The group of microorganisms cited as an example of hyperthermophiles that grow at temperatures greater than $80^\bullet\text{C}$.

Psychrophile Habitats

Environments where psychrophiles are typically found, including ice-cold areas, glaciers, and snowfields.

Thermophile Habitats

Environments where thermophiles are typically found, including hot springs and deep-sea hydrothermal vents.

Hyperthermophile Habitats

Environments such as hot springs where extreme heat-loving organisms survive temperatures greater than $80^\bullet\text{C}$.

Human Pathogens Temperature Classification

Classified as mesophiles because human body temperature ($37^\bullet\text{C}$) falls within their growth range of $20^\bullet\text{C}$ to $45^\bullet\text{C}$.

Refrigerated Food Spoilage Microorganisms

Psychrotrophs, which are capable of growing at low temperatures inside a refrigerator below $10^\bullet\text{C}$.

Low Temperature Effect on Enzymes

Enzymes become less active due to low kinetic energy, causing molecular motion and biochemical reactions to slow down.

Low Temperature Effect on Membrane Lipids

Membrane lipids pack tightly together and can solidify, rendering the membrane too rigid to function properly.

High Temperature Effect on Enzymes

Excessively high heat causes proteins and enzymes to denature, altering their shape so they cease to function properly.

High Temperature Effect on Membrane Lipids

The lipid bilayer becomes excessively fluid and loses its structural integrity.

Denaturation

The alteration of an enzyme's normal protein shape caused by excess heat, preventing it from performing its biological function.

Kinetic Energy at Low Temperatures

Reduced molecular movement in cold conditions that results in decreased enzyme activity.

Membrane Fluidity at High Temperatures

A condition occurring at high temperatures where lipid bilayers loosen and risk losing membrane integrity.

Membrane Solidification at Low Temperatures

A condition occurring at low temperatures where closely packed lipids cause the membrane to solidify and lose functionality.

4°C Plate Incubation Location

Refrigerator.

25°C Plate Incubation Location

Room temperature.

37°C Plate Incubation Location

Incubator (simulates human body temperature).

55°C Plate Incubation Location

High-temperature incubator.

4°C Culture Plate Growth

Shows growth of Pseudomonas fluorescens, confirming its ability to grow in cold conditions as a psychrotroph.

25°C Culture Plate Growth

Shows growth of mesophiles (E. coli, Serratia marcescens, Micrococcus luteus) and Pseudomonas fluorescens at room temperature.

37°C Culture Plate Growth

Shows growth of mesophilic organisms (E. coli, Serratia marcescens, Micrococcus luteus) incubated at body temperature.

55°C Culture Plate Growth

Shows growth exclusively for the thermophile Bacillus stearothermophilus in a high-temperature incubator.

Microorganism Temperature Requirements Table

Reference table categorizing psychrophiles, psychrotrophs, mesophiles, thermophiles, and hyperthermophiles with their ranges and examples.

Temperature Classification Meanings

Table defining simple descriptive meanings for cold-loving, refrigerator-growing, moderate-temperature, heat-loving, and extreme heat-loving organisms.

Protein and Lipid Temperature Effects Table

Table contrasting enzyme activity and lipid packing under conditions that are too low versus too high.

Exercise 11 Bacteria Summary Table

Table standardizing the exact classifications and temperature expectations for the 5 tested lab bacteria.

Psychrotroph vs. Psychrophile Distinction

Psychrophiles grow strictly in cold ranges ($-5^\bullet\text{C}$ to $20^\bullet\text{C}$), while psychrotrophs grow below $10^\bullet\text{C}$ but extend into the mesophile range.

Human Body Temperature Equivalent

$37^\bullet\text{C}$, the incubation temperature simulating warm-blooded host conditions ideal for mesophiles.

Room Temperature Equivalent

$25^\bullet\text{C}$, the incubation standard representing ambient lab temperature.

Refrigerator Temperature Equivalent

$4^\bullet\text{C}$, the standard cold storage temperature used to test for psychrotrophic bacterial growth.

High-Temperature Incubator Equivalent

$55^\bullet\text{C}$, the thermal environment used to select for thermophiles such as Bacillus stearothermophilus.

Staphylococcus aureus Classification

A mesophilic bacterium and human pathogen mentioned as adapted to human body conditions.

Above Maximum Growth Temperature Effect

Temperatures exceeding maximum growth limits denature essential proteins/enzymes and disrupt lipid membranes, causing growth to stop.

Below Minimum Growth Temperature Effect

Temperatures below minimum growth limits reduce enzyme kinetic energy and solidify lipids, preventing microbial reproduction.