Week 1 Flashcards
(29 cards)
On what characteristics is microbial classification
Genetics, phenotypic traits, evolution, growth and geographical distribution.
What are the structural differences between prokaryotic and eukaryotic cells?
Prokaryotes lack membrane-bound organelles and a nucleus; eukaryotes have both.
Where is DNA located in prokaryotic cells?
Nucleic region
What are the differences between Gram-positive and Gram-negative bacterial cell walls?
Gram-positive: thick peptidoglycan, stains purple;
Gram-negative: thin peptidoglycan with outer membrane, stains pink.
What are the common shapes of bacteria?
Cocci (spherical), bacilli (rod-shaped), and spirochetes (spiral).
What are the oxygen requirements for different bacterial types? (4)
A10:
• Obligate aerobes: require oxygen.
• Obligate anaerobes: cannot tolerate oxygen.
• Facultative anaerobes: can grow with or without oxygen.
• Microaerophiles: require low levels of oxygen.
What are some common metabolic activities of bacteria?
Fermentation (e.g., glucose, lactose), enzyme production
What are the functions of pili, fimbriae, capsules, and flagella in bacteria?
• Pili/fimbriae: attachment and genetic exchange.
• Capsules: protection against desiccation and phagocytosis.
• Flagella: motility.
How do yeasts and molds differ in form and reproduction? (3)
Yeasts are unicellular; molds are multicellular. Both can reproduce sexually or asexually via spores.
What are hyphae and what structure do they form?
Hyphae are filamentous structures; form a mycelium.
What structural characteristics define protozoa?
Unicellular eukaryotes without cell walls.
What are the two major forms in a protozoan life cycle?
Trophozoite (active form) and cyst (dormant form).
Helminths
What are helminths and what are the two major types?
Multicellular parasitic worms; flatworms (e.g., cestodes) and roundworms (e.g., nematodes).
What are the basic structural components of a virus?
Nucleic acid (DNA or RNA) inside a protein coat (capsid); some have a lipid envelope.
Why are viruses considered obligate intracellular parasites?
They require host cell machinery to replicate.
What are the criteria used to classify viruses?
Type of nucleic acid, capsid symmetry, presence of envelope, and replication strategy.
What are prions and how do they differ from viruses?
Infectious proteins with no nucleic acid
How do prions cause disease?
By misfolding of proteins in the brain
Name one disease caused by prions
Creutzfeldt-Jakobs disease
Why are prions so difficult to eliminate using standard sterilisation techniques?
The are resistant to heat, chemicals and radiation
What does Gram staining help to determine
Whether bacteria is Gram positive or Gram negative
Why are culture techniques important in diagnosing bacterial infections?
To grow organisms, identify them and tests susceptibility to antibiotics
What does serology detect in relation to infection?
Antibodies IgM or IgG = current or past infections
Bacillus is a what classification
Morphological
