Wednesday, September 07, 2005
BIOLOGY - Bacteria, Fungus and Virus (part 1 - the less weird and complicated part)
BACTERIA!
-Bacteria are prokaryotes
-one-celled
-circular DNA/RNA not enclosed in nucleus since they don't have one
-70s ribosomes
-no membrane bound organelles
-some have flagella
-many may have slime capsule
-eg: Escherichia coli!
some general things about bacteria
1) they are 1-10micrometres in size
2) different types of bacteria: Eubacteria, Cyanobacteria, Archaebacteria
3) there are different shapes of bacteria: rod, coccus, spiral
4) they can reproduce by binary fission, conjugation and spore formation
some useful things about bacteria
1) food production --> cheese and yoghurt
2) symbiosis: E. coli in intestines, nitrogen-fixing bacteria in plants
3) oil eating bacteria for your oil spills in the ocean
4) nutrient flow
5) genetic engineering --> Agrobacterium tumefaciens used in gene transfer
some harmful things about bacteria
Pathogenic, causes diseases like:
1) Syphillis and gonorrhoea (ooh stds!)
2) Food poisoning by things like Salmonella sp
3) Typhoid Fever
VIRUS!
-Size: 20-400nanometres
-DNA/RNA surrounded by capsid (capsomeres as subunits)
-Eg. Foot-mouth, tobacco mosiac virus, bacteriophage
-Specific in action: chicken virus won't affect plants. dots.
-Pathogenic: AIDS
-Can be used in Gene theraphy
-Doesn't feed
-Needs a host to hijack and live in
-Cannot move on its own
How does an influenza virus reproduce?
1) Virus enters host
2) Virus uncoats and releases its DNA/RNA
3) Virus hijacks host and uses the host's machinery to produce more virus DNA/RNA
4) Virus breaks out of host
FUNGI!
-Made of Hyphae (microscopic thread)
-Cell wall may contain chitin or cellulose or both
-Older ones have vacuoles
-Has a cytoplasm
-Reproduce by spores
-Saprotrophic: lives on dead organic matter and secrete enzymes. E.G. Cellulase
-Parasitic: eats into host E.G. mildew
-Multicellular
Examples of Fungi:
1) Penicillium species:
-P. notatum: Penicillin production
-P. camemberti, P. roqueforti: production of cheese
-P. griseofulvin: antibiotic against fungal skin
2) Yeast
-Unlike a normal fungus, it reproduces by budding
-It is also unicellular
-No hyphae
-However, it is considered a fungi becasue:
1) It is saprotrophic
2) It has a cell wall of cellulose and chitin
3) It has a nucleus, cytoplasm and cell membrane (so not bacetria)
4) But it has no chloroplast (...and not a plant)
More later because I really cannot tahan staring at my notes anymore. I'm going to off to make sure I don't vomit. Yay. -ziwei. again.
-Bacteria are prokaryotes
-one-celled
-circular DNA/RNA not enclosed in nucleus since they don't have one
-70s ribosomes
-no membrane bound organelles
-some have flagella
-many may have slime capsule
-eg: Escherichia coli!
some general things about bacteria
1) they are 1-10micrometres in size
2) different types of bacteria: Eubacteria, Cyanobacteria, Archaebacteria
3) there are different shapes of bacteria: rod, coccus, spiral
4) they can reproduce by binary fission, conjugation and spore formation
some useful things about bacteria
1) food production --> cheese and yoghurt
2) symbiosis: E. coli in intestines, nitrogen-fixing bacteria in plants
3) oil eating bacteria for your oil spills in the ocean
4) nutrient flow
5) genetic engineering --> Agrobacterium tumefaciens used in gene transfer
some harmful things about bacteria
Pathogenic, causes diseases like:
1) Syphillis and gonorrhoea (ooh stds!)
2) Food poisoning by things like Salmonella sp
3) Typhoid Fever
VIRUS!
-Size: 20-400nanometres
-DNA/RNA surrounded by capsid (capsomeres as subunits)
-Eg. Foot-mouth, tobacco mosiac virus, bacteriophage
-Specific in action: chicken virus won't affect plants. dots.
-Pathogenic: AIDS
-Can be used in Gene theraphy
-Doesn't feed
-Needs a host to hijack and live in
-Cannot move on its own
How does an influenza virus reproduce?
1) Virus enters host
2) Virus uncoats and releases its DNA/RNA
3) Virus hijacks host and uses the host's machinery to produce more virus DNA/RNA
4) Virus breaks out of host
FUNGI!
-Made of Hyphae (microscopic thread)
-Cell wall may contain chitin or cellulose or both
-Older ones have vacuoles
-Has a cytoplasm
-Reproduce by spores
-Saprotrophic: lives on dead organic matter and secrete enzymes. E.G. Cellulase
-Parasitic: eats into host E.G. mildew
-Multicellular
Examples of Fungi:
1) Penicillium species:
-P. notatum: Penicillin production
-P. camemberti, P. roqueforti: production of cheese
-P. griseofulvin: antibiotic against fungal skin
2) Yeast
-Unlike a normal fungus, it reproduces by budding
-It is also unicellular
-No hyphae
-However, it is considered a fungi becasue:
1) It is saprotrophic
2) It has a cell wall of cellulose and chitin
3) It has a nucleus, cytoplasm and cell membrane (so not bacetria)
4) But it has no chloroplast (...and not a plant)
More later because I really cannot tahan staring at my notes anymore. I'm going to off to make sure I don't vomit. Yay. -ziwei. again.
# we mugged! @ 1:26 AM 
