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Quick Quiz!!!! (that is a link… don’t write it down)
Vector
A vector is a piece of DNA inserted into a plasmid.
A plasmid is a circular strand of DNA within a bacteria cell.
Conjugation
Conjugation gives
genetic variety to
bacterial cells, usually
a resistance to
antibacterial agents.
Conjugation: form of
reproduction by
bacterial cells
Recall: Prokaryotes
Single-celledorganisms that do not have a membrane bound nucleus or organelle.
2 Types
Archaea
Bacteria
Archaea
Extremophiles (exist in extreme
environments)
Methanogens: convert hydrogen gas (H2)
to carbon dioxide (CO2); anaerobic
Halophiles (“salt loving”): live in very high
salt concentrations
Thermoacidophiles: live in very high
temperature and very acidic environments:
volcanic and hydrothermal vents.
Bacteria: Shapes
1. bacilli: rod shaped
2. Cocci: round/sphere
shaped
3. Spirilla: Spiral
shaped
Variations:
1. Streptococci: chains
of cocci
2. Staphylococci:
clusters of cocci
Gram stains
Categories based on chemical
components of cell walls
2 types:
Gram negative: appear reddish pink under
microscope; have a cell wall and small
amount of peptidoglycan
Gram positive: appear purple under
microscope; have simple cell walls and
more peptidoglycan
Biology of Bacteria
Cell walls contain peptidoglycan- a protein also found in cell walls of plants
Cell membranes: selective barrier to external environment
DNA: not bound by nucleus; some exists in plasmids: small circular loops of double stranded DNA
Biology of Bacteria
Capsules: outer covering of
polysaccharides; protect the cell from
drying or harsh chemicals
Pilli: short, hairlike proteins on surface of
bacteria; help bacteria adhere to surfaces
and each other; also used for conjugation
Biology of Bacteria
Endospores: dormant forms of bacterial cells; not reproductive; able to withstand harsh environmental conditions
Flagella: allow bacterial movement
Taxis: move toward or away from a stimulus
What do you think chemotaxis is?
Bacteria Monster
Use the table on the next slide to draw a bacteria “monster.”
1. Shake up your alleles (2 poker chips—stickers are dominant).
2. Drop alleles on the desk.
3. Decide if your “monster” will have or dominant or recessive phenotype.
4. Draw the phenotype for each category to create one “monster.”
Bacteria Monster
Trait: Dominant: Recessive
Shape Cocci (round) Baccili (rod)
Configuration Single Double
Color: Red Blue
Flagellum Double Single
Capsule Present Absent
Pilli Absent Present
Your turn!
• Work with your partner
• You will make 3 “monsters”
• Draw them on the back of today’s
notes
Metabolism
Heterotrophs: consume other organisms
Autotrophs: make own food
Phototrophs: make food from photons (sunlight)
Chemotrophs: make food from chemicals in the environment
Habitats
Obligate anaerobes: cannot live where
oxygen is present
Facultative anaerobes: can live with or
without oxygen
Obligate aerobes: need oxygen to live