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
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