BIO 114 Exam 2 Prep (Answered) 213 Questions and Correct
Answers With Verified Solution. 100% Correct. Updated Fall
2024/2025.
Point Sources of Contamination
- Agents that cause disease
- Enter the body through various openings
Biodiversity
The variety of life in the world or in a particular habitat or ecosystem
Runoff
Water that flows over the ground surface rather than soaking into the ground
Raw vs. Treated Sewage
Raw sewage:
- Untreated wastewater that contains human and animal waste, as well as other contaminants such as
chemicals, oils, and debris
- Can contain harmful pathogens that can cause disease in humans and animals
Treated sewage:
- Undergone a process of physical, chemical, and biological treatment to remove contaminants and
pathogens
- This process typically includes several stages, such as primary treatment to remove solids and large
debris, secondary treatment to remove organic matter, and tertiary treatment to remove nutrients and
other contaminants. The treated sewage is then disinfected using methods such as chlorination or
ultraviolet light to kill any remaining pathogens
Industrial Sewage
Used water from manufacturing or chemical processes
Transmission Routes (airborne, direct contact, insects bites, water or food borne)
,- Airborne: Occurs when infectious agents, such as bacteria or viruses, are spread through the air in
droplets or dust particles that can be inhaled by others.
EX: tuberculosis, measles, and COVID-19.
- Direct contact transmission: This occurs when infectious agents are spread through physical contact
between two individuals. This can include skin-to-skin contact, sexual contact, or contact with bodily
fluids or contaminated objects.
EX: MRSA, hepatitis B, and HIV.
- Insect-borne transmission: This occurs when infectious agents are spread by insects, such as
mosquitoes, ticks, or fleas. The insect acts as a vector, carrying the infectious agent from one person or
animal to another.
EX: malaria, Lyme disease, and Zika virus.
- Water or food-borne transmission: This occurs when infectious agents are spread through
contaminated water or food. This can happen when water sources are contaminated with fecal matter or
when food is prepared or stored in unsanitary conditions. EX: cholera, salmonella, and E. coli.
Indicator Organisms
Different fecal coliform groups are used
- Abundant in feces of warm-blooded animals
- Cost effective to isolate and quantify
- Not perfect!
Indicator Organism Characteristics
- Non-pathogen
- Have no or minimal growth in water
- Reliably detectable at low concentrations
Total Coliform
Present in the soil and water originating from surface water contamination or from a warm bodied
human and animal waste
Fecal Coliform
- Subset of the total coliform group
- From the gut and feces of warm-blooded human and animal (mainly E. coli)
Enterococci
- From the gut and feces of warm-blooded human and animal
- Survive longer than fecal coliform (E. coli)
E. Coli
A gram-negative --> coliform bacteria
Membrane Filtration Technique
, - Filter used to trap bacteria
- Filtering apparatus
- Filtered bacteria placed on media for incubation
Defined Substrate Test
- Water sample mixed with media sealed in a tray, incubated for 24 hours.
- Coliform bacteria hydrolase substrate (ONPG) with the enzyme B-D-galatosidase producing yellow
nitrophenyl
- E. coli present reacts with flurogenic substrate (MUG), producing a fluorescent end product under UV
light
Deficiencies with Indicator Organisms
- Re-growth in aquatic environments including sediments, beach rock and sand.
- Re-growth in distribution systems.
- Suppression by high background bacterial growth.
- May not be indicative of a health threat, especially in runoff
- No numerical relationship with viral, protozoan pathogens
To cause an infection, a pathogen must:
- Reach the right host
- Reach the right tissues in the host
- Overcome body's immune system
- Build a population
What are common transmission routes for pathogens?
Common transmission routes:
- Airborne
- Direct contact
- Insect Bites
- Water or food borne
What are ideal characteristics for an indicator organism?
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