Bacteria

Prokaryote – single celled with no nucleus

• Eubacteria – peptidoglycan (a carbohydrate) cell wall

• Archaebacteria – cell wall of lipids, no peptidoglycan in the cell wall

Identifying Prokaryotes

• Shape a. bacilli – rod shaped b. cocci – spherical shaped c. spirilla – corkscrew shapehttp://biology.clc.uc.edu/graphics/bio106/bacteria.jpg

Identifying Prokaryotes

• Cell Wall – use gram stain i. gram positive has peptidoglycan wall ii. gram negative has no peptidoglycan wall

• Movement – may or may not move >flagella >lash, snake, or spiral forward >glide on slime like secreted layer

Metabolic Diversity

• Heterotrophs: chemotrophs & photoheterotrophs

• Autotrophs >photoautotrophs – ex. Cyanobacteria http://steel.ced.berkeley.edu/cris/

hiddenecologies/HE/wp-content/uploads/ 2006

Metabolic Diversity

• >chemoautotrophs – energy from chemical reactions is used to make food (from ammonia, hydrogen sulfide (H2S), nitrites, sulfur, or iron)

Growth & Reproduction

• Binary fissionhttp://www.biology-resources.com/drawing-amoeba-reproduction.html

Growth & Reproduction

• Conjugation http://americanscientist.org/Libraries/images/thumbnail/20033711443_307.gif

Growth & Reproduction

• Spore Formation: structures of DNA & some cytoplasm (formed when conditions were unfavorable for growth) remain dormant for months or years until the right conditions existhttp://ppdl.purdue.edu/PPDL/images/daylily_rust_spores400x.jpeg

Importance of Bacteria

• Decomposers – recycle nutrients & maintain equilibrium

• Nitrogen fixers – changenitrogen gas into useable compound plants can usewww.windows.ucar.edu/earth/climate/images/ nitrogencycle.jpg

Importance of Bacteria• Human use – make food & beverages, clean up oil

spills, remove waste products from ground, synthesize drugs & chemicals, make vitamins our bodies need (E.coli in large intestine)

www.javno.com/slike/slike_3/r1/g2007/ www.fotosearch.com/LIF145/pdb07006/ http://library.thinkquest.org/J002755/graphics/vitamins.gif

Viruses

• Virus: particles of nucleic acid, protein, & sometimes lipids (typically DNA or RNA core with a protein coat) >only reproduce by infecting living cells >use living cells to make more virusesImage by Karsten Schneider/Science Photo Library

Viruses

• Capsid: protein coat of a virus >capsids bind to cell host & “trick” the cellto let the virus inside the healthy cell

• Bacteriophages: viruses that only infect bacteria

Viral Infection

• Lytic – virus enters a cell, makes copies of itself, & causes the cell to burst

• Lysogenic - virus combines its DNA with the host cell and the viral DNA replicates with the host’s DNA

Viral Infection

Retroviruses

• Viruses that contain RNA

• Named retro because they copy genetic information from RNA to DNA (usually genetic information is copied from DNA to RNA

Retroviruses

HIV VIRUS

• www.chm.bris.ac.uk/.../levasseur/images/hiv.GIF

The “take-home” message

• STAY HEALTHY

• WASH YOUR HANDS, ETC.