PMI02-2001 Microorganism structure and function

Description

Distinguish between eukaryotes/ prokaryotes+ characterise microorganisms into bacteria, viruses, fungi and protozoa. basic structure of viruses, their method of replication and the characteristics used for classification. basic structure of bacteria and methods for bacterial identification and classification, including morphology and nucleic acid methods. basic structure of fungi and protozoa. Define normal flora, opportunist infections, and pathogeNESIS Role of host in pathogensis
Evian Chai
Flashcards by Evian Chai, updated more than 1 year ago
Evian Chai
Created by Evian Chai over 3 years ago
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Question Answer
4 classes of microorganisms? 1. TSEs 2. Virus 3. Bacteria 4. Eukaryotic microbes eg. funghi/protozoa
What are TSEs? What are they caused by?Give an example Misfolded prion proteins Contact with other misfolded proteins Eg. Kuru, scrapie
Bacteria, Eukaryote, Virus: What cannot be seen in microscope? What isn't capable of free growth? What has genes seperated from cytoplasm by membrane? What has RNA? 1. Virus 2. Virus+ some bacteria 3. Eukaryote 4. Virus
What are the two different ways nucleic acids are packaged in viruses? 1. Icosahedral (12 faced) 2. Helical (helix)
The genome of virus contains ... OR ... in ... or ... strands DNA, double RNA, single
What are the two ways viruses can be packaged? Examples of each 1. Naked, with only a protein coat (eg. bacteriophage, coronavirus) 2. Enveloped, with plasma membrane (eg. HIV, retrovirus)
Process of viral replication? 1. Lands on host 2. Enters via fusion w membrane/translocation/endocytosed 3. Translation/transcription/reverse transcription/integration to replicate 4. Burst cell open
What shape is bacilli and give an example? What shape is cocci and give an example? What shape is spirochaetes and give an example? Does shape indicate relatedness? Rectangular, e. coli Round, s. mutans Squiggly, Lyme's disease No
What does gram staining stain for? What features do gram negative bacteria have that positive don't? Peptidoglycan on gram positive bacteria Outer membrane, LPS, lipoprotein, periplasmic space
What are ways to classify bacteria based on colony characteristics? 1. Hemolytic activity 2. Surface texture 3. Colony morphology/size 4. Indicator dyes 5. Different nutrients
How does alpha hemolysis bacteria work? Locally breakdown cells
How does beta hemolysis bacteria work? Strongest, secrete hemolytic cells to create visible zone
How does gamma hemolysis bacteria work? Weakest, only breaks cells it touches
What are two types of biochemical tests for classifying bacteria? 1. Sugar fermentation profiles (eg. gas or acid producing) 2. Enzyme profiles (eg. coagulase)
How does typing based on antigenic structure work? It is based on the proteins on bacteria unique to its bacterium (since antibodies only bind to specific proteins) Agglutination occurs as specific antibodies clump to the specific bacteria
What does serotyping use to classify bacteria? Each bacteria is its own serotype based on the proteins it has on its surface Serotyping is performed with antisera (blood serum with antibodies in it)
What does phage typing use to classify bacteria? Using phage (bacterial viruses) to recognise specific surface proteins
What is a phage/bacteriophage? A virus that replicates within bacteria/microorganisms
What does genetic typing use to classify bacteria? What are the 4 ways? Using DNA sequence (CAN BE used for all pathogens) 1. Plasmids 2. Sequence and RFLP 3. Probes 4. Polymerase chain reaction (PCR)
Plasmids are commonly used to distinguish between .... Smaller plasmids move .... Same species, different strain Further from the baseline
How does RFLP work? Restriction endonucleases cut specific sequences into specific fragments to distinguish between DNA sequences
what are 2 other ways to analyse bacterial types other than the ones mentioned? 1. Antimicrobial sensitivity 2. Serum antibody (agglutination test in serum)
Do prokaryotes have internal membranes? What differs between prokaryote and eukaryote ribosomes? No P=70s, E=80s
Features of fungi Is protozoa single or multi cellular? Single or multicellular Digest food w extracellular enzymes Can be dimorphic Single
Give an example of a dimorphic funghi? Candida albicans can exist in yeast form or hyphae form
Difference between yeasts and moulds? Example of each Yeast: Usually single celled unless dimorphic (also grows as hyphae) Eg. candida, cryptococcus Moulds: Grow as long hyphae only eg. penicillium, aspergillus, fusarium
What is the fungal cell wall made of? Mannoproteins Chitin Glucans (B1,3 and B1,6
Who came up with the germ theory of life, rabies/anthrax vaccine, and diseases of wine and beer? Louis Pasteur
Who linked bacteria with disease, came up with postulates, and discovered tuberculosis/cholerae? Robert Koch
What are Koch's postulates? 1. The bacteria must be present in every case of the disease 2. Must be isolated from host and grown in pure culture 3. Disease must be reproduced when bacteria is inoculated in a healthy host
How do commensals benefit us? 1. Competitive exclusion to prevent opprotunistic bacteria from infecting (eg. nutrient competition, pH balance, immune system) 2. Nutrient synthesis
What are opportunistic/pathobionts bacteria? Bacteria that can be commensal or pathogenic based on certain environmental factors
The following lead to which opprotunistic bacteria: Antibiotics HIV Trauma 1. Salmonella, C. difficile 2. TB, candida 3. S. aureus
What is the host parasite relationship? The state of the host determines whether the parasite causes disease eg. E. coli O157 affects humans not cattle, and is obtained by eating beef
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