Unit 5- Microbiology & Prokaryotes
No description yet. This curated deck is ready for daily study.
Card preview (24)
How does prokaryotes differ from eukaryotes?
Prokaryotes have no membrane bound organelles, no nucleus and small in size.
What advantage does the simplicity of prokaryotic cells provide?
It allows for rapid growth and division due to a high surface area.
What is significant about antibiotics?
• Derived from soil microorganisms. • Potent bacteriocides with high therapeutic index which means low toxicity to human cells but high toxicity to bacteria.
What is taxonomy?
The classification of organisms into ordered groups.
What is nomenclature?
The labelling of groups or individual members within those groups.
What are the levels of taxonomy for cellular living organisms?
Life, Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.
What are the three domains of life?
Bacteria, Archaea, and Eukaryotes.
How are bacteria and archaea different despite both being prokaryotes?
• Bacteria have peptidoglycan in their cell walls. • Archaea have a distinct evolutionary history based on mRNA sequencing.
What are the four kingdoms in the eukaryotic domain?
• Protista: Includes algae, Protozoa, and slime molds • Fungi: Includes yeast (unicellular) and molds (multicellular). • Animalia: Includes multicellular animals like parasites. • Plantae: Includes multicellular plants that perform photosynthesis.
What characteristics are used to classify bacteria?
• Morphology • Staining reactions • Culturing characteristics • Biochemical reactions • Antigenic capability • Nucleotide base composition (GC-ratio) • Presence, location, & shape of an endospore • Atmospheric preferences
What are the atmospheric preferences of bacteria?
• Anaerobos: Grow without oxygen • Aerobes: Requires oxygen • Facultative anaerobes: Tolerates hypoxia • Microaerophiles: Prefer lower oxygen levels • Capnophiles: Thrive in elevated carbon dioxide levels.
What is the structure of the bacterial genome?
A single circular double-stranded DNA molecule, sometimes with plasmids coding for non-essential functions.
What it is the bacterial capsule, and what is this function?
• A rigid cell wall surrounding the cell membrane, composed of loose polysaccharides. • Maintains cell shape, protects phagocytosis, and contributes to virulence.
How does the composition of the bacterial capsule affect virulence?
Capsule composition varies across phyla, influencing bacteria’s ability to survive in the human body & evade immune responses.
What are fimbriae, and what is their function?
Hair-like structures protruding from bacterial cells involved in bacterial conjugation.
What are pili, and what role do they play in bacteria?
Structures used by bacteria to share and swap plasmids during conjugation, often transferring antibiotic resistance.
What are endospores, and why are they significant?
Dormant bacterial structures formed under unfavourable conditions; they are extremely resistant to heat, dehydration, radiation, & chemicals.
What is glycocalyx, and what are its types?
An outermost layer of prokaryotic cells made of polysaccharides/polypeptides. Types include: * Slimes: Unorganised, loose, water-soluble, sticky, & essential for biofilm formation. * Capsules: Organised, firmly attached, & protective.
What are the functions of glycocalyces?
• Protect the plasma membrane from stresses, desiccation, or chemicals. • Help bacteria attach to surfaces, initiating disease. • Aid in biofilm formation (slime only).
What are biofilms, and where can they form?
Aggregations of microorganisms embedded in a slime matrix, forming on living tissues (e.g. tooth paste) or non-living surfaces (e.g. catheters).
Why are biofilms more resistant to antibiotics and stresses?
Cells communicate via quorum sensing, coordinating actions like replication or secretion of harmful substances.
What is the composition of bacterial cell walls, an dhow does it differ from eukaryotes?
• Bacteria: Peptidoglycan’s (NAG & NAM connected by amino acid cross bridges). • Eukaryotes: Pectin or cellulose (e.g. in fungi & plants).
What is the function of the bacterial cell wall?
Provides structural support, protecting the cell from osmotic pressure, drought & chemicals.
What is a pathogen?
A microorganism capable of causing disease in plants, animals, or insects.