Bacteria

Unit 7: The Protists of Curriculum

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

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

Bacilli

Cocci

Spirilla

Streptococci

Staphylococci

Lets Draw

1. Bacilli

2. Cocci

3. Spirilla

Lets Draw

4. Streptococci

5. Staphylococci

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

Gram Stain

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

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

Capsules

Pili

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?

Endospore

Endospore

Flagellum

Bacteria Monster

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

Example:

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

Reproduction

Most bacterial cells reproduce through an

asexual process known as binary fission.

Reproduction

Transformation: takes in DNA from its

outside environment

Conjugation: two bacteria bind together

and one cell transfers DNA to the other

Transduction: virus copies itself within a

host also transferring DNA from bacteria