L11 - Classification, structure and replication of m/o Flashcards
what are the 3 main domains?
prokaryota
eukaryota
archaea
what are the 5 main kingdoms?
Bacteria
protista
fungi
plantae
animalia
describe a bacteria cell
- single cell organism
- lack membrane bound nucleus
- prokaryotes
[have a cell wall, cell membrane, sex pilus, flagellum,
fimbriae and capsule]
what is the bacterial organ of locomotion?
flagella
what does a monotrichous flagella look like?
one at the back
A
what does a Lophotrichous flagella look like?
many at the back
B
what does a Amphitrichous flagella look like?
one on either side of cell
C
what does a Peritrichous flagella look like?
lots on either side
D
what specialised structures to bacteria have to aid adhesion to host cells and colonisation?
Pili and fimbriae [Gram negative bacteria]
what is the function of a bacteria’s capsule of slime layer?
Polysaccharide material protecting bacteria from phagocytosis, dessication,
immune attack, antibiotics
what does the India ink test, test for?
- add India ink
- If it has a capsid, it will not be taken up (white)
- If it has a slime layer, it will be taken up (dark)
what is biofilm?
Structure containing lots of bacteria adhering together to provide protection from
antibiotics
what is an endospore?
An endospore is a dormant, tough, non-reproductive structure
- during a harsh environment they produced spores to allow them to survive for many years
- not active or able to reproduce
- when conditions are Bette they can return to the active form
into what categories can you classify bacteria?
- gram stain
- cell shape
- endospore
- atmospheric preference
- fastidiousness
- key enzymes
- DNA
what is gram stain used for?
Gram stain is used to identify if the bacteria is gram positive or
negative
what colour does gram positive stain?
purple
crystal violet binds to the cell wall
what colour does gram negative stain?
red
crystal violet doesn’t bind to the cell wall
what does cocci refer to?
round shape
what does coccus refer to?
one round bacteria
what does diplococci refer to?
two round bacteria
what does streptococci refer to?
multiple round bacteria
what does bacilli refer to?
rod shaped
what does bacillus refer to?
one rod bacteria
what does diplobacilli refer to?
two rod bacteria
what does streptobacilli refer to?
multiple rod bacteria
what does coccobacillus refer to?
between round and rod
what ways can bacteria replicate?
- binary fission
- conjugation
- transformation
- transduction
what is binary fission?
cells divide to give two identical daughter cells
[asexual, creates new bacteria, but no exchange of genetic material]
what is conjugation?
transfer of transposable elements
[Creates no new bacteria, some genetic diversity.]
what is transformation?
picking up genetic material from the environment
[Creates no new bacteria, introduces some genetic diversity to the population.]
what is transduction?
transfer of genetic information via a viral vector
[Introduces some genetic diversity into a population.]
which type of bacterial replication results in genetic diversity?
conjugation
transformation
transduction
which type of bacterial replication results in new bacterium being made?
binary fission
what is the name for transfer of genetic information via a viral vector?
transduction
what is the name for picking up genetic material from the environment?
transformation
with reference to binary fission, what is doubling time?
amount of time it takes for one cell to become 2
NB: bacteria have different doubling times - important consideration for antibiotic treatments
which type of bacterial replication uses a sex pilus?
conjugation
what is the process of binary fission?
- DNA replication
- Cell elongation
- Contraction of FtsZ ring
- Cell wall synthesis and Cell division
which bacterial replication process results in both bacteria having the plasmid?
conjugation
what is the process of transduction?
o Attachment of the viral cell to the bacterial cell
o Release of its DNA into the bacterial cell
o Interaction with the chromosomal DNA of the bacterial cell
o Breaking up of the DNA
o Results in the proteins of the virus
what domain are fungi?
eukaryotic
what domain are bacteria?
prokaryota
what is a fungi cell wall made of?
chitin
[Structure of N–Acetylglucosamine - Structure is similar but it is different to plants (cellulose)]
what is the most common yeast infection?
thrush caused by C. (candida) albicans
what is thrush caused by?
fungi - C. (candida) albicans
how do fungi replicate?
sexually
asexually via spores
which method of fungal replication results in genetic diversity?
sexually
which method of fungal replication results in no genetic diversity?
germination of spores
- Mitosis from mycelium (1n)
what are the two types of parasite?
protozoa (protists)
helminths (Animalia)
what are the 4 types of protozoa?
● Flagellates – e.g. Giardia [flagella to move]
● Amoebae – e.g. Entamoeba [change its shape]
● Cilliates – e.g. Balantidium [cilia to move]
● Apicomplexa (or Sporozoa) – e.g. plasmodium
how do protozoa replicate?
Reproduce asexually (fission)
what are the components of a virus?
- nucleic acid
- protein coat
- envelope
describe the viral life cycle?
- attachment/penetration
- uncaring
- Early viral proteins produced
- Genome replication
- Late viral proteins produced
- Virion assembly
- Virion release
during viral replication, how does the virus attach/penetrate a cell?
endocytosis
direct membrane fusion
with reference to the viral replication cycle, what is meant by the step uncaring?
● Genome is released from capsid (protein coat) during / after
penetration
● Genetic material targeted to nucleus
with reference to the viral replication cycle, how does a cell perform the final step of virion release?
lytic - bursts cell
lysogenic
how do retroviruses replicate?
➢ Unusual
➢ Reverse transcriptase converts RNA to DNA
➢ Integrated in host DNA (integrase)
➢ Uses host replication system [people are affected by this virus indefinitely]
which characteristics do you use to classify a virus?
● Nature of the nucleic acid: RNA or DNA
● Symmetry of the capsid
● Presence or absence of an envelope
● Dimensions of the virion and capsid
what classification of virus is the herpesvirus?
dsDNA
what classification of virus is the parvovirus?
ssDNA
what are prions?
➢ Misfolded protein
➢ Unlike viruses, no genetic material
➢ Can be inherited, spread via contaminated material or occur spontaneously
➢ Aggregate and cause misfolding of native proteins – chain reaction
Examples:
- Creutzfeldt-Jakob Disease
- Bovine spongiform encephalopathy
- Scrapie
