Quiz 5 Short Answer

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Questions and Answers

What organism group do fungi belong to, based on their nutrient requirements?

Fungi are heterotrophs, requiring organic carbon for nutrition.

Describe the difference between saprotrophs and symbiotic fungi.

Saprotrophs decompose dead organic matter, while symbiotic fungi interact with other species, often benefiting both organisms.

What is the primary component of the cell wall in fungi?

The cell wall of fungi is made up of chitin.

What is the term for the long branching structures found in molds?

These structures are called hyphae. Signup and view all the answers

How do zygomycetes differ from ascomycetes in their reproductive structures?

Zygomycetes form zygospores during sexual reproduction, while ascomycetes produce ascospores. Signup and view all the answers

In throat cultures, what does the presence of clear zones on a blood agar plate signify?

Clear zones indicate B-hemolytic bacteria that completely break down red blood cells. Signup and view all the answers

What type of culture medium is typically used to diagnose urinary tract infections?

Eosin Methylene Blue (EMB) and Blood agar plates are used for urine cultures. Signup and view all the answers

Why is a 'clean catch' method important when collecting urine samples?

It helps to minimize contamination and ensures accurate results. Signup and view all the answers

What is the gas environment required for the growth of obligate anaerobes?

Obligate anaerobes require an oxygen-free environment to grow. Signup and view all the answers

What is significant bacteriuria in terms of UTI diagnosis?

Significant bacteriuria is defined as 100,000/ml of one type of organism. Signup and view all the answers

What is the purpose of the GasPak system in culturing facultative pathogens?

The GasPak system creates an anaerobic environment by removing oxygen, allowing facultative pathogens to grow. Signup and view all the answers

Identify two types of vectors that transmit disease-causing organisms.

Human vectors and mechanical vectors. Signup and view all the answers

What role do antibodies play in the immune response?

Antibodies are proteins produced to neutralize or destroy foreign substances, including pathogens. Signup and view all the answers

Explain the importance of washing steps in the ELISA test.

Washing steps remove non-bound reagents and prevent interference with test accuracy. Signup and view all the answers

What results indicate a positive reaction in an ELISA test?

A color change in the well indicates the presence of antibodies or antigens. Signup and view all the answers

Why is a negative control group necessary in ELISA testing?

A negative control group ensures that any observed results are due to the experimental variable and not random fluctuations. Signup and view all the answers

Describe how the Biolog system identifies bacteria.

The Biolog system identifies bacteria based on their metabolic properties using a 96-well plate. Signup and view all the answers

What does a purple color indicate in a Biolog system test?

A purple color indicates that tetrazolium dye has been reduced, signifying bacterial growth and metabolic activity. Signup and view all the answers

How is turbidity measured to estimate the concentration of bacteria in suspension?

Turbidity is measured by using a turbidimeter to determine the percentage of light transmitted through the sample. Signup and view all the answers

What issues can arise from inoculating too much bacteria in a Biolog system test?

Inoculating too much bacteria can lead to cross-contamination and inaccurate readings of growth patterns. Signup and view all the answers

Study Notes

Fungi

Fungi are heterotrophs, meaning they require organic carbon for survival.
They are often saprotrophs, decomposing dead organic matter.
They can form symbiotic relationships with other species like algae or bacteria.
Fungi serve as a food source and are involved in food production for humans and other organisms.
Fungi have cell walls composed of chitin.
They can be multicellular (molds) or unicellular (yeasts).
Fungi have hyphae, long branching cellular structures forming mycelium (an invisible mat).
Vegetative hyphae grow along the substrate.
Reproductive hyphae extend upwards to produce spores.
Fungi exhibit thermal dimorphism, growing as molds at room temperature and as yeast at 37°C.
Some fungi are opportunistic pathogens, infecting weak or immunocompromised individuals.
Zygomycetes: Form zygospores during sexual reproduction and sporangiospores during asexual reproduction (e.g., Rhizopus stolonifer).
Ascomycetes: Form ascospores during sexual reproduction and conidiospores during asexual reproduction (e.g., Penicillium notatum, Aspergillus niger).
Basidiomycetes: Form basidiospores during sexual reproduction (e.g., mushrooms).

Infectious Disease

Throat Cultures: Blood agar plates (containing 5% sheep's blood) are used to determine hemolysis:
- Alpha-hemolysis: Partial breakdown of red blood cells (RBCs), green coloration.
- Beta-hemolysis: Complete breakdown of RBCs, clear zones.
- Gamma-hemolysis: No breakdown of RBCs. (Streptococcus pneumoniae, Streptoccocus pyogenes examples)
Urine Cultures: Diagnose urinary tract infections (UTIs), most commonly caused by E. coli.
- Use Eosin Methylene Blue (EMB) and Blood Agar (BA) plates.
- Sterile sample collection crucial.
- “Clean catch” method for urine collection.
- Significant bacteriuria is defined as ≥100,000 organisms/mL of one type.
Anaerobic Pathogens: Require GasPak system (removal of free oxygen using a special jar with sachets/chemicals) for growth on TSA plates. (Obligate anaerobes)
Facultative Pathogens: Can grow with or without oxygen.
Vectors: Transmit diseases through various means:
- Food/water
- Respiratory droplets
- Sexual contact
- Insect vectors (mechanical/biological)

Immunology

Antigens trigger an immune response; Antibodies are produced to fight them.
ELISA Test: Used to detect antigens, antibodies (HIV, EBV, pregnancy tests, etc.).
- Colorimetric detection (color change).
- Key steps: Label wells, add viral antigen, wash, add test reagent, add secondary antibody, add substrate.
Infectious Mononucleosis (Kissing Disease): Transmitted through saliva.
EBV: Associated with chronic fatigue syndrome.
Biolog System: Identifies bacteria based on metabolic properties (using 96-well plates, carbon sources, sensitivity tests).
- Purple color indicates positive reaction (bacteria growth)
Steps include well preparation, sample inoculation, incubation, and analyzing results using light/dye methods

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Description

This quiz explores the diverse characteristics and classifications of fungi, including their heterotrophic nature, structural features, and reproductive methods. Learn about the different types of fungi, such as Zygomycetes and Ascomycetes, and their roles in ecosystems and human life.