Biology Chapter 28: Microbiology

5 stages of "Origin of Microbial Life"
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5 stages of "Origin of Microbial Life"
stage 1: organic monomers
stage 2: organic polymers
stage 3: protobionts
stage 4: living cells
prokaryotes:

nucleoid
circular, free-floating DNA
simpler DNA
no membrane-bound organelles
smaller
binary fission
unicellular
anaerobic & aerobic
**archaea and bacteria are both prokaryotes, but are NOT close relatives.
**bacteria are most common prokaryotes
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eukaryotes:

nucleus
linear DNA in nucleus
complex DNA
membrane-bound organelles
larger
mitosis/meiosis
multicellular
aerobic
...
both prokaryotes and eukaryotes:

chromosomes
DNA as genetic material
ribosomes
cytoplasm
plasma membrane
sometimes cell walls
vacuoles
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Horizontal Gene transfer:

1. conjugation: donor passes DNA to recipient cell via sex pilus

2. transformation: bacterium takes up DNA released into medium by dead bacteria

3. transduction: viruses carry portions of bacterial DNA from one bacterium to another

**can transfer ANTIBIOTIC RESISTANCE TO OTHER BACTERIA
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bacterial diseases
--e. coli
--streptococcus ( more different types of human disease are caused by bacteria from this genus than by any other type of bacterium): strep throat, pharyngitis, impetigo, scarlet fever, rheumatic fever,
--staphylococcus aureus: MRSA
--tuberculosis
--food poisoning: botulism, salmonella
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bacterial chemoautotrophs: use gases like CO2, H2

bacterial photoautotrophs: use solar energy to make their own food
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Antibiotics work by:
--interfering with cell wall syntheses
--breaking cell walls
--interfering with protein synthesis (via ribosomes)
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the genome of a retrovirus is RNA, but these viruses are able to convert their genome into DNA bc. they contain an enzyme called reverse transcriptase; (ex. HIV)
retrovirus
Virus reproductive cycle:
1. attachment
2. entry & uncoating
3. replication
4. biosynthesis
5. assembly
6. budding
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