Bacteria & Archaea Ch10.1 7th Pdf

Chapter 10 Section 1

BACTERIA & ARCHAEA

Objectives  Describe the characteristics of prokaryotes  Explain how prokaryotes reproduce  Relate the characteristics of archaea

Quick Questions…  Question: How much bacteria are in a

handful of soil? A single gram of soil?  Question: What are the 2 single-celled

organisms without a nucleus?  Question: What are 3 shapes of bacteria?

Domains:  All living things fit into one of three domains:  Bacteria  Archaea  Eukarya

 Bacteria & Archaea are single-celled organisms – the oldest forms of life on Earth

http://www.windows.ucar.edu/earth/Life/images/domains_sm.gif

Characteristics:  More bacteria on Earth than any other living

thing  Too small to be seen without a microscope  Not all the same size (some are actually quite

large!)  Ex: Found inside the surgeonfish Fig. 1, pg. 246

Giant Bacteria

(o.6mm long)

http://www.epscor.dbi.udel.edu/outreach/science/images/02_EpulopisciumFischelsoni2.jpg http://saltwater-aquarium-guide.net/images/blue-tang.jpg

3 Main Shapes:  Rod shaped (bacilli)

 Spherical (cocci)  Spiral shaped (spirilla)  All have a rigid cell wall that gives them their

shape

Bacilli

http://www.uga.edu/caur/bacteria.jpg

http://faculty.marianopolis.edu/bio-nya/bacilli1000X.jpg

Cocci

http://www.bacteria-world.com/cocci-bacteria-bloom.jpg

http://www.bioweb.uncc.edu/1110Lab/notes/notes1/labpics/Cocci%20100x.jpg

Spirilla

http://www.nzetc.org/etexts/Bio18Tuat03/Bio18Tuat03_104a(h280).jpg

http://www.uic.edu/classes/bios/bios100/labs/spirilla.jpg

A look at all three…

http://www.ilri.org/InfoServ/Webpub/Fulldocs/ILCA_Manual4/images/FIG%207%20P16.gif

No nucleus!  Prokaryotes

 Function as independent organisms  May form strands or films

 Simpler and smaller than eukaryotes  Reproduce differently than eukaryotes

Prokaryote Reproduction  Binary Fission: single-celled organisms split

into 2 single-celled organisms  DNA is not surrounded by a nucleus

(membrane)  DNA is in circular loops

Binary Fission:  1st step: Cell’s DNA is copied; DNA binds to different places on the inside of the cell membrane  Next step: loops of DNA separate as cell gets larger  Finally: when cell is about double in size the membrane pinches inward; new cell wall forms &

separated into 2 new cells (each with any exact copy)

Binary Fission:

http://diverge.hunter.cuny.edu/~weigang/Images/06-11_binaryfission_1.jpg

Endospores  Most bacteria do well in warm, moist places

 Some bacteria die in cold, dry places  Bacteria become inactive and form endospores  a thick-walled protective spore that forms inside a

bacterial cell and resists harsh conditions  Contains genetic material and proteins

 When conditions improve endopores break open and bacteria become active again

Prehistoric Bacteria: “trapped”

http://museumvictoria.com.au/prehistoric/images/mn005267_sm.jpg http://www.micro.cornell.edu/cals/micro/research/labs/angert-lab/images/endospore.jpg

The Domain Bacteria:  Has more individuals than all other domains

combined do  Classified by the way they get food  Consumers  Decomposers  Producers  Ex: Cyanobacteria

Cyanobacteria  Producers

 Usually live in water  Contain chlorophyll (blue, green, and red pigments)  Possibly gave rise to the 1st plants on Earth

Cyanobacteria: many forms

http://4.bp.blogspot.com/_puTVILFyI9M/SAS85CLxr9I/AAAAAAAAAHg/_gJlmw0yUC0/s320/Cyanobacteria-Types.jpg

The Domain Archaea:  3 main types:  Heat lovers  Very hot water (60˚ - 80˚C or more than 250˚C)  Salt lovers  Live in Dead Sea & Great Salt Lake  Methane makers  Live in swamps & animal intestines

Archaea  Can live where nothing else can

 Usually with little or no oxygen  Beneath 430m of ice in Antarctica; 8km below

the Earth’s surface; in the Earth’s oceans  Not all archaea have cell walls; the walls are chemically different than bacteria

Hot springs Archaea

http://www.popsci.com/files/imagecache/article_image_large/files/articles/hotspring_800.jpg

Quick Quiz:  How are prokaryotes different than

eukaryotes?  What are the 2 main types of archaea?