BACTERIA & ARCHAEA

Chapter 10 Section 1

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://saltwater-aquarium-guide.net/images/blue-tang.jpg

http://www.epscor.dbi.udel.edu/outreach/science/images/02_EpulopisciumFischelsoni2.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).jpghttp://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?