Quiz 5 Multiple Choice

Fungi

• Fungi are heterotrophs, meaning they require organic carbon for survival.
• They are saprotrophs, decomposing dead organic matter.
• They can form symbiotic relationships with other species, such as algae or bacteria.
• Fungi are a food source and important for food production for humans and other organisms.
• Their cell walls are composed of chitin.
• They can be multicellular (molds) or unicellular (yeast).
• Fungi have hyphae, long, branching cellular structures.
• Hyphae can form an interwoven mass called mycelium.
• Vegetative hyphae grow along the substrate.
• Reproductive hyphae extend upwards to produce spores.
• Fungi exhibit thermal dimorphism, meaning mold growth occurs at room temperature, while yeast forms at 37 degrees Celsius.
• Some fungi are opportunistic pathogens, exploiting weak or immunocompromised individuals.

Types of Fungi

• Zygomycetes: Form zygospores during sexual reproduction and sporangiospores during asexual reproduction. A common example is Rhizopus stolonifer.
• Ascomycetes: Form ascospores during sexual reproduction and conidiospores during asexual reproduction. Penicillium notatum and Aspergillus niger are examples.
• Basidiomycetes: Form basidiospores during sexual reproduction. They typically lack well-defined asexual reproduction.

Lab 11: Infectious Disease

Throat Cultures

• Bacteria, like certain Streptococcus species, obtain iron from blood.
• Blood agar plates, containing 5% sheep's blood, are used.
• Alpha-hemolysis (partial breakdown of red blood cells): Greenish color.
• Beta-hemolysis (complete breakdown of red blood cells): Clear zones.
• Gamma-hemolysis (no breakdown): No color change.

Urine Cultures

• Diagnose Urinary Tract Infections (UTIs), most commonly caused by E. coli.
• Uses Eosin Methylene Blue (EMB) and Blood agar (BA) plates.
• Collecting a clean-catch urine sample is crucial.
• Urine is sterile in the body. Contamination occurs upon leaving the body.
• Significant bacteriuria occurs at a count of 100,000/mL of a single organism type.
• UTIs arise due to the presence of bacteria from the intestinal tract, with the anus being proximal to the urethra.
• Samples must be tested or refrigerated promptly to prevent bacterial growth.

Anaerobic Pathogens

• Anaerobic pathogens do not require oxygen to grow.
• Require GasPak System for anaerobic growth.

Vectors

• Vectors are disease-causing organisms transmitted through various pathways.
• Examples include food, water, respiratory droplets, and sexual contact.
• Vectors can be biological (carrying microbes internally, e.g., malaria mosquitos) or mechanical (carrying microbes on their bodies, e.g., flies).

Lab 12: Immunology

ELISA Test

• Used to detect antigens and antibodies.
• Used in diagnoses like HIV, EBV, pregnancy tests, drug screening, and food allergies.
• Uses a colorimetric method with a secondary antibody to indicate the presence of the targeted antigen or antibody.
• Procedures include adding antigens, incubating, washing, adding test reagents, incubating and checking for colorimetric reaction.

Biolog System

• Identifies bacteria based on metabolic properties.
• Uses a 96-well microplate to test carbon sources (sugars, amino acids) and sensitivity to various conditions (antibiotics, salinity).
• Positive metabolic tests exhibit purple color reactions due to reduced tetrazolium dye.
• Procedures include swabbing bacteria, preparing cell suspension, using a turbidimeter, adding suspension to wells, incubating, and reading results.