MICROBIOLOGY Flashcards
(67 cards)
1
Q
What are the 3 domains
A
eukarya, bacteria and archaea
2
Q
outline eukarya
A
eukaryotic organisms
-4 kingdoms: animalia, plant, fungi, protista
3
Q
outline archaea
A
organisms live under extreme environmental conditions
4
Q
difference between bacteria and archaea
A
the presence of 16 s rRNA
5
Q
4 basic shapes of microorganisms
A
sphere
rod
spiral
commas
arrangements of single, pairs, chains and clusters
6
Q
archaea and eukarya similarities
A
genes encoding protein replication, transcription and translation
7
Q
archaea and bacteria similarities
A
genes for metabolism
8
Q
archaea uniqueness
A
- unique rRNA
- capability of methanogenesis
- lack peptidoglycan
- membrane lipids that lack phosphate groups.
9
Q
what is proteglycan
A
- complex proteins joined to polysaccharide chain.
- 4 amino acids not found in normal proteins.
- present in baceterial cell wall
10
Q
outline bacteria
A
single celled microbes
11
Q
what is lipopolysaccharide
A
- lipopolysaccharide (LPS) are polysaccharides extending off the membrane that act as antigens and receptors.
- gram -ve bacteria.
12
Q
what is an acid fast cell wall
A
- unique types of lipids.
- acid fast stain can be used
- mycolic acid present
13
Q
what are cell wall deficient bacteria
A
- mycoplasmas
- vary in shape
14
Q
outline capsules
A
- composed of polysaccharides extruded from the cell.
- barrier of protection(stops drying and infection)
- adhere
- avoid phagocytosis
15
Q
what are fimbriae
A
- adhesions bristle like projections
- gram -ve bacteria
16
Q
what are pili
A
- adhesions tubules of protein
- extruded, attach and then contract.
17
Q
cell division depending arrangement
A
- division in 1 plane: chain,
- many planes: random
18
Q
what are endospores
A
- spore formation in unfavourable conditions to store nutrients close to death to survive later.
- not reproductive
- formed by asymmetrical division.
19
Q
what is the microbiome
A
the ecological community of microorganisms that share our body.
20
Q
what is a carrier
A
- infected but not obviously diseased.
- potential source of infection
21
Q
what is an acute carrier
A
incubatory: incubating pathogen but not yet ill
convalescent: recovered but has a large number of the pathogen.
22
Q
define disease
A
any abnormal condition in cells, tissues or organs that leads to a symptomatic alteration in normal functioning.
can be hereditary, physiological or infectionious
23
Q
define infection
A
growth of a microorganism in the body where it shouldn’t be growing. Infection doesn’t always lead to disease.
24
Q
what is a primary pathogen
A
a microorganism that can cause disease and is not part of normal microbiota. will cause disease despite conditions
25
what is a secondary/opportunistic pathogen
a microorganism that can cause disease and may be part of normal microbiota. requires predisposing conditions to cause disease. this could be an altered microbiota (antibiotics), altered immune system.
26
what are endogenous agents
predisposing factors already in body
27
what are communicable disease
spread from another being. can be from direct contact or indirect from contact of highly contaminated objects.
28
why are human bodies desirable to microorganisms
- consistent physical environment
- rich source of nutrients
- different regions to support different species growth.
29
outline basic steps of pathogenesis
```
1 exposure
2 adherence
3 penetration/invasion of cells
4 colonisation and growth
5 cell and tissue damage
6 spread to others of population
```
30
outline phagocytosis
phagocytic cells can engulf pathogen in a vesicle called a phagosome. a lysosome fuses with this phagosome which activates killing pathways to destroy pathogen
31
how does secretion help pathogen
- secreting specific portions to stop antigen recognition.
- to kill phagocytic cells
- stop phagosome binding to lysosome
32
how living in host cell help pathogen
- incognito from body
| - comfortable conditions.
33
define a virus
- infectious agents, packaged set of genes in transit between host cells.
- unable to derive metabolic energy or reproduce by themselves.
- reproduce by self-assembly of virus encoded components in host cell.
- RNA or DNA.
34
shapes of virus
icosahedral: single or double protein coat. this is the capsid that holds the genome
envelope: some viruses also have a membrane envelope enclosing the capsid.
Helical (tube capsid instead of icosahedral)
complex (spider like
35
basic steps of virus replication
```
1 attachement to specific receptors
2 entry & uncaring of genomic material
3 synthesis of new viral components
4 assembly of new viral particles
5 release of virions into body.
```
36
what affects virus host range
- type of receptor virus binds to
| - replication factors
37
what do we classify viruses by
- (+)sense or (-)antisense of genome
- DNA or RNA
- single or double stranded (ss or ds)
38
explain anti sense and sense
a virus is dependent on one of these strands (to code for specific proteins etc as they are not the same) so the complimentary strand is used to produce mRNA to then produce the original strand again.
39
outline retrovirus replication
this type of replication classifies a virus as a retrovirus.
- needs viral enzyme (encodes virus production)
- reverse transcription from RNA to DNA without multiplying genome number.
- new Viral DNA inserted into host cells DNA then replicated by cell.
40
temperate bacteriophage life cycle
- injects virus DNA into bacteria
- then undergoes lytic cycle where phage DNA is replicated, the cell is lysed and the phages released.
-or the lysogenic cycle can occur where the phage DNA joins bacteria DNA and stays in cells throughout asexual reproduction. Later these cells can undergo lytic cycle to release phages.
41
what is antigenic drift
- mutations of virus
| - immune memory is not perfect which may cause slight disease
42
what is antigenic shift
- a single cell infected with 2 virus particles joins the viruses together.
- large changes to the virus occur = little to no immunity which can cause epidemics
43
outline influenza
- 8 strands of -ssRNA genome encodes for 11 proteins
- pleomorphic, spherical, enveloped virions
- -ssRNA going through +s to then create -s replication.
- 1 copy of each of the 8 strands is produced for the new virion
44
outline HIV-1
- spread by homo and heterosexual intercourse
- replicates by retrovirus pathway
- reverse transcriptase helps to convert +ssRNA to dsDNA
45
what a protists
- eukaryotes that are not plants, animals or fungi.
- unicellular
- free-living, symbiotic or parasitic.
- a/sexual, binary fission, spores and cysts
46
how are members of major groups of protists related
DNA similarities and common ancestors
47
outline SAR
- diverse group of stramenopiles, alveolates and rhizarians
| - includes photosynthetic organisms and amoeba
48
outline ARCHAEPLASTIDA
- the first photosynthetic eukaryotes
- red algae mostly saltwater
- green algae mostly freshwater
- land plants
49
green algae 2 types
volvox: -2 types of differentiated cells,
- cell wall is biflagellated cells embedded in ECM.
- first multicellular organism with specialised cells to die without killing whole organism
chlamydomonas: unicellular
50
outline excavata
- "excavated" feeding groove on one side of the cell body,
- no plastids,
- highly reduced mitochondria.
51
outline unikonta-amoebazoa
amoeba with lobe- or tube-shaped pseudopodia.
- archamoeta - no/reduced mitochondria
- discosea - flat, naked amoeba
52
what is an amoeba
type of unicellular organism that has the ability to alter it's shape primarily by extending and retracting pseudopods.
53
outline unikonta-opsithokonta
- diverse group of animals, fungi and protists.
- protists include nuclearids which are amoeba that feed on algae and bacteria.
- chanoflagellates, have a collar around their flagellum, closely related to animals
54
define fungi
- eukaryotes that have cell walls but are not plants.
- unicellular (yeast)
- multicellular filaments (hyphae and mycelia).
- decomposing organic matter.
- spore formation through a/sexual reproduction.
55
sexual reproduction of fungi
fusion of nuclei to produce diploid zygote a spores are produced through meiosis.
56
what are zygomycetes
major fungal group
-mycelia that are not septate therefore multinucleate.
e.g: mucor (bread mould)
57
what are asomycetes
major fungal group
- mycelia that are septate.
- produce endogenous ascospores
e.g: saccharomyes and penicillium
58
what are basidiomycetes
- have mycelia that are septate.
- produce exogenous basidiospore.
e.g: mushrooms, mycelium grows upwards and forms inside of mushroom. DNA codes for mushroom and spores are formed by meiosis.
59
what type of pathogen are fungi
opportunistic
60
outline candida infections
- major pathogen is candida albicans
- yeast that is part of normal microbiota
- budding cells.
- biofilm helps with pathogenesis
61
outline cryptococcosis
- major pathogen is cryptococcus neoformas which is yeast found in soil
- polysaccharide capsule helps pathogenesis
- infection in lungs due to ingestion of infectious particles
62
outline aspergillosis
- aspergillus fumigatus common pathogen
- airborne soil fungus
- mycelial form
- infection in lungs where spores germinate in lungs & form fungal colonies
63
outline malaria
- most deadly vector-borne disease.
- transmitted by anopheles and mosquitos
- caused by plasmodium species (alveolate SAR).
64
outline plasmodium development
- first grows into schizont in the liver.
- schizont ruptures letting out into the body.
- get into red blood cells and keep forming schizonts or produce gametocytes which are then extracted by another mosquito.
- sporozoites form in the mosquito which are released
65
outline leishmniasis
caused by leishmania spp (excavata), vector of sandflies and normal host of small rodents.
- sandfly injects into skin and are phagocytised by macrophages.
- then grow in macrophages which multiply asexually
- released from macrophage and extracted by another sandfly
- promastigotes formed in sandfly
66
outline giardiasis
- caused by giardia lamblia
- commonly known as travellers diarrhoea
- symptoms of diarrhoea
67
outline the life cycle of dictostelium
- solitary amoebas are fertilised to produce a zygote which then undergoes meiosis to form amoebas.
- later aggregation of amoebas.
- fruiting bodies are produce which release spores of emerging amoeba
