CHAPTER 19:BACTERIA

Unit 7: The Protists of Curriculum

Lets Kahoot!!!

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-celled organisms 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:

4. Streptococci: chains of cocci

5. 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

Activity!Bacteria Monster

Bacteria Monster

Use the table on the next slide to draw a bacteria “monster.”

1. Shake up your alleles (pennies—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 MonsterTrait: 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