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Biology 114 Exam 2 | Questions And Answers Latest {} A+ Graded | 100% Verified
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Biology 114 Exam 2 | Questions And Answers Latest {} A+ Graded | 100% Verified
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Biology 114 Exam 2 | Questions And Answers Latest {2024- 2025} A+ Graded| 100% Verified
Point Sources of Contamination - - Sewage (Raw or treated)
- Industrial wastewater
- Combined sewage overflows
Non-point Sources of Contamination - - Contaminated runoff (includes sewage)
-Aerial deposition
-Combined sewage overflows
Pathogen - - 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
What are general sources of water contamination? - Point sources:
- Sewage
- Industrial water
Non-point sources:
- contaminate runoff
(includes sewage)
, - Aerial deposit
How does a pathogen cause infection? - 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? - - Non-pathogen
- Have no or minimal growth in water
- Reliably detectable at low concentrations
What are the 3 groups of indicator bacteria? Be able to describe how they are different from each other.
- - Total coliforms
- Fecal coliforms
- E. coli
- Enterococci
What are common tests for the indicator bacteria? How is each test done? What do you find out? -
Common Tests:
- Total coliform test: This test uses a selective and differential medium to detect the presence of
coliform bacteria, which are commonly found in the intestinal tract of humans and animals. The test
involves adding a water or food sample to the medium and incubating it at a specific temperature for a
certain period of time. The presence of coliforms is indicated by the production of gas or acid in the
medium.
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