Microbiology Midterm 1

They allow bacteria to attach to surfaces in water, helping them access nutrients and resist flushing by currents.

Phytoplankton, such as cyanobacteria, primarily fix carbon and nitrogen through photosynthesis, supporting marine food webs.

The low oxygen levels in the profundal zone stimulate the growth of anaerobic bacteria, which carry out processes like sulfate reduction.

<p>Bioluminescence aids luminescent bacteria in symbiotic relationships by attracting prey for benthic-dwelling fish.</p> Signup and view all the answers

<p>They require low light conditions to thrive, which are more prevalent in deeper waters where photosynthesis is less active.</p> Signup and view all the answers

<p>Healthcare-associated infections are infections acquired while receiving treatment in a healthcare facility, known as nosocomial infections, and they affect 1 in 25 hospital patients.</p> Signup and view all the answers

<p>A compromised host is an individual whose resistance to infection is weakened due to factors like disease or therapy, such as a cancer patient undergoing chemotherapy.</p> Signup and view all the answers

<p>The three risk factors are microorganisms in the hospital environment, the weakened status of the host, and the chain of transmission within the hospital.</p> Signup and view all the answers

<p>HAIs can be prevented through rigorous hygiene practices, proper sterilization of medical instruments, and effective protocols to control disease transmission.</p> Signup and view all the answers

<p>It is often insufficient because HAIs typically result from a combination of the three risk factors, whereby one alone may not trigger an infection.</p> Signup and view all the answers

<p>Nitrogen-fixing bacteria</p> Signup and view all the answers

<p>Denitrification</p> Signup and view all the answers

<p>Chemoautotrophic bacteria</p> Signup and view all the answers

<p>Sulfates</p> Signup and view all the answers

<p>Anaerobic respiration</p> Signup and view all the answers

<p>Phosphate ions</p> Signup and view all the answers

<p>By producing acid that solubilizes phosphate in rocks</p> Signup and view all the answers

<p>There are no volatile phosphorus-containing products.</p> Signup and view all the answers

<p>Hot hydrogen peroxide or UV light.</p> Signup and view all the answers

<p>Ionizing radiation, measured in Grays.</p> Signup and view all the answers

<p>Methanogens are the metabolic group of anaerobic bacteria encouraged by sludge digestion systems.</p> Signup and view all the answers

<p>0.005–0.1 kGy.</p> Signup and view all the answers

<p>Higher BOD levels can deplete oxygen in water, negatively affecting fish welfare.</p> Signup and view all the answers

<p>Bacterial endospores, needing 10–50 kGy.</p> Signup and view all the answers

<p>Thermophilic anaerobic spoilage occurs at high temperatures, while flat sour spoilage involves mesophilic bacteria at moderate temperatures.</p> Signup and view all the answers

<p>Microwaves cause water molecules to oscillate, generating heat through friction.</p> Signup and view all the answers

<p>High Pressure Processing (HPP) and Pressure-Assisted Thermal Sterilization (PATS) are two methods utilizing high pressure.</p> Signup and view all the answers

<p>HACCP identifies critical points in food production where contamination may occur.</p> Signup and view all the answers

<p>Foods must be sterilized before filling.</p> Signup and view all the answers

<p>Viruses require doses of 10–200 kGy to be effectively sterilized.</p> Signup and view all the answers

<p>The packages are not sterilized after sealing.</p> Signup and view all the answers

<p>It specifies that the coliform bacteria are sourced from fecal matter, indicating potential health risks from contaminated water.</p> Signup and view all the answers

<p>Flocculants such as alum coagulate colloidal impurities and microorganisms, allowing them to settle out during sedimentation.</p> Signup and view all the answers

<p>It aerates wastewater, promoting the growth of aerobic microbes that metabolize organic matter and significantly reduce BOD.</p> Signup and view all the answers

<p>Trickling filters typically remove 80–85% of BOD from sewage.</p> Signup and view all the answers

<p>It breaks down organic solids in sedimented sludge using anaerobic bacteria, producing methane and carbon dioxide.</p> Signup and view all the answers

<p>Oxidation ponds allow for settling of sludge and support aerobic decomposition, cultivating algae for oxygen production.</p> Signup and view all the answers

<p>Tertiary sewage treatment involves the removal of remaining BOD, nitrogen, and phosphorus through physical and chemical treatments.</p> Signup and view all the answers

<p>Chlorination disinfects the sewage, killing harmful microorganisms to ensure safe water release.</p> Signup and view all the answers

<p>Its main purpose is to remove solids and reduce BOD by approximately 25–35%.</p> Signup and view all the answers

<p>Fecal coliforms specifically indicate contamination from human or animal waste, whereas total coliforms may originate from various environmental sources.</p> Signup and view all the answers