bacteria & archaea ch10.1 7th pdf
DESCRIPTION
Information obtained from Holt Science and Technology: Life Science. Austin: Holt Rinehart & Winston, 2007. Print.TRANSCRIPT
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?