Transcript DDA #11 – Dirty Places - Effingham County Schools

DDA #11 – Dirty Places

Of the four places you swabbed in the lab
last class, which do you think will have the
most bacterial growth? Why?
They Are Everywhere
An introduction to bacteria
* = don’t have to write
Prokaryotes
Prokaryote: Single-celled organism that
lacks a nucleus (also called bacteria)
 Cover almost every cm2 of earth!

Size Matters
Prokaryotes = 1-5 micrometers
 Eukaryotes = 10-100 micrometers

Vs.
One to Two
*Until recently all prokaryotes were one
kingdom, Monera
 Monera is now split into 2 domains

Now three domains
1) Eubacteria
2) Archaea
3) Eukaryota
Eubacteria
Largest of prokaryote groups
 *Have cell walls that contain
peptidoglycan (carbohydrate)

Shapes

Three Shapes (sketch each)
1) Bacili
3) Spirilla
(rod-shaped)
(spiral or corkscrew)
2) Cocci
(spherical)
“Strep” throat
Cell Walls

Two Types:
– Gram-Positive
 Thick peptidoglycan walls
 Turn dark purple when stained
– Gram-Negative
 Much thinner walls inside an outer lipid layer
 Appear pink or light red
Energy

Heterotrophs

Chemoheterotrophs:
– Take in organic molecules for both energy
and supply of carbon (this is also us)

Photoheterotrophs:
– Use photosynthesis for energy but also need
organic compounds for carbon
Autotrophs

Photoautotrophs:
– Use light energy to convert CO2 and H2O to
food (like plants)
– Ex: cyanobacteria

Chemoautotrophs:
– Use chemical energy to convert CO2 and H2O
to food
Releasing Energy

Obligate Aerobes:
– Require constant supply of oxygen

Obligate Anaerobes:
– Do not require oxygen . . . It kills them

Facultative Anaerobes:
– Do not require oxygen, but can live with it
– Ex: E. coli
*Growth and Reproduction

Some bacteria can divide every 20
minutes
– If there was unlimited resources 1 bacteria
could grow into a mass 4000 times the mass
of earth in just 48 hours!!!
Compare and Contrast
Grab a book and turn to page 475
 Compare and contrast the three ways that
bacteria can grow and reproduce
 A ven-diagram works well
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