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23 terms

3: Environmental Microbiology

A critters gotta do what a critters gotta do
STUDY
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Algae
Unicellular and multicellular organisms formerly classified as plants, occurring in fresh or salt water or moist ground, that have chlorophyll and other pigments but lack true stems, roots, and leaves.
Dates to the Precambrian period
They have a wide range of reproductive strategy, from asexual cell division to sexual reproduction
Harmful Algae
Harmful algal blooms may cause harm through the production of toxins or by their accumulated biomass
Fungi
Fungi break down organic material and continue to cycle of nutrients through the ecosystem.
Harmful Fungi
Because fungi are more chemically and genetically similar to animals than other organisms, this makes fungal diseases very difficult to treat
Bacteria
Major players in the cycles of carbon, nitrogen and sulfur. They can remain dormant for an extended period of time, making them easily spreadable.
They lack the membrane-bound nuclei of eukaryotes.
Aerobic bacteria
Thrive in the presence of oxygen
Anaerobic bacteria
Cannot tolerate gaseous oxygen
Facultative anaerobes
prefer growing in the presence of oxygen, but can continue to grow without it
Decomposition
The breakdown of dead organisms, and the release of nutrients back into the environment
Why is the nitrogen cycle necessary?
Plant rely on nitrogen from the soil for their health and growth. They cannot acquire it from the gaseous nitrogen in the atmosphere. The primary way nitrogen becomes available to them is through nitrogen fixation by bacteria
Viruses
Viruses depend on the cells that they infect to reproduce. When found outside of the cells, viruses exist as a protein coat or capsid. The capsid encloses either DNA or RNA which codes for the virus elements
When it comes into contact with a host cell, a virus can insert its genetic material into its host. An infected cell then produces more viral proteins and gentical material instead of its usual products
The Four Main Requirements for Bacterial Growth are
1.Food
2. Moisture
3. Warmth
4. Time
How do bacteria like their environment?
They like neutral conditions (PH of 7) and will not grow in foods with a PH below 4.5

Bacteria that grow in low temperatures (below 20 degrees Celsius) are called psychrophiles
Bacteria that grow at high temperatures (above 45 degrees Celsius) are called thermophiles
Why do bacteria like nitrates?
They're better than day rates.

ba-dum-dum-ca
What are the optimal growth temperatures for microbes?
Most pathogens like warmth and are known as mesophiles. They will grow at temperatures between 5 degrees and 63 degrees celcius (aka the danger zone Que scary music). Mesophiles have an optimum temperature growth of 37 degrees celcius
Most bacteria will become inactive under five degrees celcius, but Listeria has to ruin it for everyone by growing very slowly below 5 degrees
What is the recommended temperature and time for killing pathogens during cooking?
70 degrees Celsius for 2 minutes
Why did the bacteria fail his math test?
He thought multiplication was the same as division!

eh!? good one.
Coliform Bacteria
Coliforms are not a single type of bacteria, but a grouping of bacteria that includes many strains. They live in soil or vegetation and in the GI tract of animals. Coliforms enter water supplies from the direct disposal of waste into streams or lakes or from runoff
What is the standard by which microbial contamination is measured?
Total coliform
Nosocomial Infections
Infection acquired in a hospital.

Problematic because people in hospitls are already in a poor state of health. If a patient is treated with immunosuppresants, antacid treatment, or antimicrobal treatment, the may be vulnerable for nosocomial infections
How to control nosocomial infections
1. Wash yo hands, fool
2. Cleaning, disinfection, and sterilization
3. Personal Protective Equipment
4. Antimicrobial surfaces
Disinfection
Disinfection refers to the use of liquid chemical on surfaces and at room temperature to kill disease causing microorganisms.

Less effective than sterilization because it does notkill bacterial endospores
Sterilization
The process intended to kill all microorganisms. It is the highest level of microbial kill that is possible. Sterilizers may be heat, steam, or liquid. The effectiveness of sterilizers are determined by:
1. Mechanical indicators
2. Heat sensitive indicators
3. Biological testing <--- most important