Microbes In Human Health And Disease (MODULE 2A/2B) Flashcards
(186 cards)
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Viruses prions are referred to as A - cellular
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Within the scope of medical microbiology chart: Etiologic Agents of Infectious Diseases is broken down into Cellular (Eukaryotes and Prokaryotes) and A - Cellular (Viruses, Viroids, and prions)
*Look at chart on slide 7 for reference
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Prokaryotes vs. Eukaryotes
Prokaryotes: single - cell organisms, no real nucleus, no membrane-bound organelles, unique cell wall (bacteria)
Eukaryotes: real nucleus, membrane-bound organelles; some have cells lack walls (plants, fungi), some do not (animals)
- Protozoa: single-cell organisms similar to animal cells, belong to ‘parasites’
- Fungi: can be single- or multicellular, unique cell wall
- Helminths: multicellular, belong to animals, cells have no cell wall, most closely related to humans, belong to ‘parasites’
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Fungi can only be single celled
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Fungi can be single- or multicellular, unique cell wall
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Prions are misfolded protiens
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What are Viroids?
RNA molecule (so far only know to cause diseases in plants)
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Viruses: RNA or DNA surrounded by a structural protein layer, many with additional structural features; no metabolic capability
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Compare and contrast prokaryotic cells and eukaryotic cells.
Prokaryotic cells - small, simple (0.1-5mm); unicellular; No nucleus; Circular DNA; No membrane-bound organelles
Eukaryotic cells - Large, complex (10-100mm); Uni- or multicellular; Nucleus present; Linear DNA; Membrane-bound organelles present
BOTH: Cytoplasm; DNA and RNA; Ribosomes
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Bacteria can synthesize cholesterol
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Prokaryotic cells have a higher protein content
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What is the major component of the prokaryotic cells wall?
Peptidoglycan (protection from osmotic pressure)
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Gram-positive bacteria have less peptidoglycan than gram-negative bacteria.
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Gram-positive bacteria has more peptidoglycan than gram-negative bacteria
What is the role of lipopolysaccharide (LPS) in the gram-negative bacteria of the cell wall of prokaryotic cells?
A substance that can lead to our immune system reacting to them, because it acts as an antigen and leading to an up regulation of the immune response.
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Gram-positive has a high susceptibility to penicillin, and gram-negative has a low susceptibility to penicillin
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Gram-positive has high susceptibility to lysozyme, and gram-negative has low
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Gram-positive has _____ susceptibility to lysis by complement and gram-negative has _____.
Low
High
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Exotoxin are present in some species of gram-positive bacteria and a few species of gram-negative bacteria
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What is the wax like substance that covers gram-positive bacteria?
Mycolic acid
Name the four identifications of flagella.
Monotrichous - one strand
Amphitrichous - two strands
Lophotrichous - three strands
Peritrichous - multiple strands
Name the sticky, bristle-like appendages structure that has a purpose for biofilm formation.
Fimbriae
What is the purpose of Pili?
Hollow tubes (made of proteins), make a connection between two cells
Purpose: transfer of DNA between two cells (conjugation)
What are endospores and why are they clinically important?
Found in some gram-positive genera of bacteria
Clinically important: certain species of Bacillus and Clostridium
Resistant to commonly used methods of sterilisation (difficult to get rid of)
*Cells can toggle back between an endospores stage and a vegetative stage
Vegetative Cells vs Endospores
Vegetative cells - sensitive to extreme temperatures and radiation; gram-positive; physiological water content and enzymatic activity; capable for growth and metabolism
Endospores - resistant to extreme temperatures and radiation; do not absorb gram stain; need special endospore stains; dehydrated; no metabolic activity; dormant; no growth or metabolic activity
Explain fermentation
Pyruvate ——> Glucose
*when glucose is broken down to pyrucate for the purpose of ATP production, and NAD+ is necessary for glycolysis.
Reasons for not completely oxidizing glucose and/or other nutrients (to CO2):
- lack of O2
- lack of genes for some enzymes of the cellular respiration process