The Nature of Infection Flashcards
Revision
What is another word to describe bacteria?
Eubacteria
What is another word to describe eukaryotes?
Eukaryia
What is the definition of protozoa?
Single celled animals, eukaryotes
What is the definition of fungi?
Higher plant like organisms, Eukaryotes
What is the definition of bacteria?
Generally small, single celled prokaryotes.
What is the definition of viruses?
Very small obligate parasites, non-living
What are 8 identifiable characteristics of eukaryotes?
- Size 5-50mms
- Complex (Compartmental)
- Frequently multi-cellular
- Linear chromosome + Histones
- Introns/Exons
- 80S Ribosomes
- No/Flexible Cell wall (sterols)
- Cell cycle (mitosis/meiosis)
What are 8 identifiable characteristics of a prokaryote?
- Size 0.5-10mms
- Simple (relatively)
- Often single celled
- Single circular chromosome
- Gene structure (introns rare)
- 70S Ribosomes Co-transcription/translation
- Rigid cell walls (PG)
- Rapid cell cycle
What are the classic 3 Domains (Carl Woese’s three-domain tree)?
Bacteria
Archaea (Euryarchaeota and Cenarchaeota)
Eukarya
What is the new two domain tree?
Bacteria
Tack (Eury-, Thaum-, Algar-, Cren-, Eukarya, Archaea (Korarchaeota))
What are 16 things that make up the structure of a cell?
- Cell membrane
- Nucleus
- Centriole/ Centrosome
- Nucleolus/ Ribosomes
- Endoplasmic reticulum (ER)
- Cytosol
- Mitochondria
- Golgi
- Cytoskeleton
- Secretory Vesicles, Lysosomes
- Plasma membrane
- Cell wall (Peptidoglycan)
- Nucleoid (DNA & associated proteins)
- Ribosomes
- Cytoplasm
- Capsule, Flagellar, Pili
What are 4 things that a nucleoid contains?
- Contains DNA and proteins
- No nuclear membrane
- Chromosomes single circular molecule
- Primitive DNA segregation machinery
What is the process of energy generation in cytoplasmic membrane?
Electrons released from high energy compounds in cytoplasm.
Reach membrane and passed through a series of electron acceptors.
As a consequence protons passed outside the membrane producing a +ve charge and proton gradient across the membrane
What are 5 features of a cell wall in a gram positive bacteria?
- Rigid layer
- Barrier
- Repeated polysaccharide structure
- Gram +ve. Thick multi-layer PG
- Target of penicillin
Gram positive have a thick cell wall. Gram negative bacteria have a thin cell wall
What are 5 features of a cell wall in a gram negative bacteria?
- Rigid layer
- Barrier
- Repeated polysaccharide structure
- Gram-ve
- outer membrane
- Periplasm
- Thinner PG layer
- Target of Penicillin
What is the role of Lipopolysaccharide (LPS)?
- Gm-ve
- Outer membrane asymmetric
- Surface nearly all LPS
Glycolipid - lipid A
- Core polysaccharide, O-chain/antigen
Structural role
Antigen and bacterial toxin
What is the Cell Wall (Peptidoglycan) composed of?
N-acetyl muramic acid (NAM) and N-acetyl Glucosamine (NAG)
It is a gram-negative single layer
What are 5 features of a gram positive cell wall (Peptidoglycan)?
- Rigid layer
- Barrier
- Repeated polysaccharide structure
- Gram +ve
- Thick multi-layer PG
- Target of penicillin
Gram positive cell walls are thick.
What are 5 features of a gram negative cell wall (Peptidoglycan)?
- Rigid layer
- Barrier
- Repeated polysaccharide structure
- Gram-ve
- Outer membrane
- Periplasm
- Thinner PG layer
- Target of Penicillin
Gram negative cell walls are thin.
What are the roles of Lipopolysaccharide (LPS)?
- Gm-ve (gram negative)
- Outer membrane asymmetric
- Surface nearly all LPS
- Glycolipid
- lipid A
- Core polysaccharide, O-chain/antigen
Structural role
Antigen and bacterial toxin
What are Flagella and Fimbriae and what are their roles?
- Gm-ve and Gm+ve
- Arrangement
- Developmental stage
- Flagellin
- protein unit making up a multi stranded filament with core
- Gm+ve Fimbriae
- non-flagella protein appendages
- Gm-ve Pilus
- no motor, Pilin repeated protein unit.
Adherence and sex
What varies between different Bacterial Pili?
Length, number, arrangement, shape and functions vary.
What is the role of Prokaryotic Protein Synthesis and what is the chain of processes that lead to the formation of a protein?
The target of several classes of antibiotic. Distinct proteins. Co-transcription/ translation. Cytoplasmic membrane. No polyadenylation of transcript. Target for antibiotics.
Gene (DNA) Transcription mRNA (DNA dependent RNA polymerase) Ribosome (tRNA) Translation Protein 2nd, 3rd, 4th structure Export/Assembly/ Processing
What is the process of planktonic growth?
Most bacteria don’t exist on their own, most exist in communities
(Development; Complex colony formation & Biofilms)
Multicellularity; Colony development & differentiation.
Multicellularity leads to a more sophisticated approach.
What structures form the basic structure or Prokaryotes?
- Cytoplasm
- Cytoplasmic or plasma membrane
- cell wall
- Outer membrane and LPS
- Chromosome
- Ribosome
- Pilli, Fimbriae, and Flagella
- Sonication and Ethanol
- Penicillin and Glycopeptides
- Antibiotic uptake and inflammation
- Gyrases antibiotic target
- Protein synthesis inhibitors
- Attachment, motility, invasion, sex and pathology.
What food do prokaryotes use for prokaryotic growth?
Food
- C source organic e.g. proteins/sugars inorganic e.g. fix CO2.
- O&H, N source, e.g. Amino acid Ammonia Inorganic salts P, S, K, Mg, Ca, Fe
- Trace elements Zn, Cu, Mn, Ni, Mo
- Vitamins (small organic cofactors) e.g. Biotin Folic Acid, Niacin.
What factors affect the rate of prokaryotic growth?
Food Temperature - Psycrophiles (low temp) - Thermophiles (high temp) - Mesophiles (body temp) Hydrogen Ion Conc. Osmotic protection - NaCl Oxygen - Aerobes - Micro-aerobes - Facultative anaerobes - Obligate Anaerobes - Capnophilic
What are the phases of a bacterial growth curve?
Lag phase
Exponential Phase
Stationary Phase
Decline Phase
