Microbes – Bacteria, Viruses,

Protists and Fungi

Biology – Bacteria Notes

and Slides

• Warm-Up:

– Welcome to 4th Quarter! Whoohoo!

– Turn in any missing assignments (a.k.a Virus

Webquest)

– Note your seats will change tomorrow.

• Today in Science:

– This Week in Biology

– Bacteria Presentation and Notes

– Bacteria Slides

This Week in Biology

Monday Bacteria Presentation and

Notes, Bacteria Slides

Tuesday Hamburger Lab – Design

Wednesday Hamburger Lab –

Experiment

Thursday Set-up Antibiotic Lab

Bacteria Choice Activity

Friday Bacteria and Virus Quiz

Hamburger Lab – Data,

Analysis, and Conclusion

Choice Activity DUE

Table of Contents

Page Content Date

68 Natural Selection Notes 3/6/17

69 Speciation Notes 3/7/17

70 Virus Notes 3/20/17

71-73 Microbes in School Lab 3/22/17

74 Bacteria Notes 4/3/17

75 Bacteria Slides 4/3/17

Prokaryotes

• Prokaryote – unicellular organism

without a nucleus

– DNA is found in the cytoplasm

Classifying Prokaryotes

• 2 Kingdoms of Prokaryotes

– Eubacteria

• Have peptidoglycan in cell walls

• Includes most of the bacteria

– Archaebacteria

• Live in unusually harsh

environments such as hot springs,

stomach acid, and salty water.

• No peptidoglycan in cell walls

• Cell membranes and rRNA different

than Eubacteria

Identifying Prokaryotes

Prokaryotes can be identified based

on the following:

1. Shapes

2. Cell Walls

3. Movement

Shapes3 Shapes

1.Bacilli – rod shaped

2.Cocci – spherical shaped

3.Spirochetes – spiral & corkscrew

shaped

Cell Walls

• Eubacteria can be separated based

on Gram staining.

– Gram Positive

• Eubacteria cell walls have a thick layer

of peptidoglycan that absorbs only

violet dye and appears purple.

– Gram Negative

• Have an extra layer of lipid on the cell

wall that stops the purple stain from

entering and appears pink

Movement

• Stationary

– Some bacteria do not move.

• Flagella (tails)

– Whip like structures used for movement.

• Other

– Spiral shaped bacteria move in a

corkscrew Motion

– Myxobacteria produce a layer of slime to

glide in.

Obtaining Energy• Autotrophs (Make their own energy)

– Photoautotroph – uses the sun

– Chemoautotroph – oxidize inorganic compounds as food.

• Heterotrophs (Rely on other organisms for energy)– Fermentation – ferment sugars

– Saprophytes – feed on dead things

• Photoheterotrophs (A mix between the two)– are both autotrophic and heterotrophic

– Use energy from the sun, but they require organic substances such as alcohol, fatty acids or carbohydrates.

Growth and Reproduction• Bacteria divide very quickly, as often as once

every 20 minutes!

• Binary Fission

– Asexual reproduction where the bacteria

divide into identical cells.

Endospore

• Endospore – a structure produced

in unfavorable conditions

- A thick internal wall encloses the DNA

and cytoplasm

Gene Transfer

(Bacterial Evolution)

• Mutation – random changes in DNA-passed on to daughter cells

-one of the main way prokaryotes evolve

• Conjugation– Bacteria make a bridge and exchange

genetic material.

• Transformation– Bacteria incorporate DNA from dead

bacteria.

• Transduction– Use viruses to transfer DNA from bacteria to

other bacteria.

Importance of Bacteria

• Decomposers

• Producers

• Nitrogen Fixers

Decomposers• Decomposers

– Bacteria that break down complex

molecules of dead organisms

(trees, corpses) into simple molecules

such as water, nitrogen compounds,

and CO2

Producers

• Producers – food chains are

dependent on bacteria for

producing food

– 1 cyanobacterium (Prochlorococcus) is

the most abundant photosynthetic

organism – makes over ½ of food in the

open ocean

Nitrogen Fixers• Nitrogen Fixers – converts nitrogen

into a form plants use (N2 to NH3)

– 90% of the nitrogen organisms use comes

from fixation

– Fix nitrogen to ammonia.

– Ex: Rhizobium grows in nodules of the roots

of soybeans and other legumes. It is a

mutual relationship where the plant provides

nutrients for bacteria and the bacteria

converts nitrogen for the plant.

Bacteria and Disease

Pathogens – Disease causing agents.

2 Ways Bacteria cause Disease1. Damage Tissues – damage tissues of the

infected organisms directly by breakingthem down for food.– Ex: Tuberculosis – bacteria break down lung

tissue.

2. Toxins – release toxins that harm the organism.– Ex: Streptococcus: causes strep throat, if

untreated, the bacteria releases toxins causing a rash known as scarlett fever.

Bacterial Diseases

Human Uses of Bacteria

• Food

– Bacteria are used to make cheese, yogurt, buttermilk, sour cream, pickles, sauerkraut and vinegar.

• Drugs (Medicines)

– Also used to synthesize drugs such as insulin.

• Environmental Use

– Certain bacteria are used to digest petroleum after an oil spill.

Bacteria Slides

Name of

Bacteria

Drawing Shape Color Gram - / +

Practice

Spirillum voltans

Staphylococcus aureus

Bacillus anthracis