2/28/12 What is a halophile? Key Term: archaea

3/1/12 What compound makes up the cell wall of a bacterium? Key terms: same as yesterday

Prokaryotes Domain Bacteria Domain Archaebacteria Domain Bacteria Domain Archaea Domain Eukarya Common ancestor

Bacteria Structures

Bacteria Structures/Functions StructureFunction FlagellaTail-like structure for movement PiliProjection of cell wall for sticking to surfaces Cell wallMaintains shape of cell; protects the cell Cell membraneRegulates what leaves and enters the cell DNAStores hereditary information RibosomesBuilds proetins

Bacteria Structures/Functions StructureFunction Flagella Pili Cell wall Cell membrane DNA Ribosomes

Prokaryote Structure Unicellular – bacilli, cocci, spirilli Size – 1/10 size of eukaryote cell 1 micron (1um) Internal structure – no internal compartments no membrane-bound organelles only ribosomes – circular, naked DNA not wrapped around proteins prokaryote cell

Bacterial diversity rods and spheres and spirals… Oh My!

Bacteria live EVERYWHERE! Bacteria live in all ecosystems – on plants & animals – in plants & animals – in the soil – in depths of the oceans – in extreme cold – in extreme hot – in extreme salt – on the living – on the dead

Archaebacteria Extremophiles: – Thermoacidophiles – love heat (up to 110’C) and acidic environments; require sulfur; anaerobic ex: Sulfolobus, Pyrodictium – Halophiles –love environments with high salt concentrations like the Great Salt Lake and the Dead Sea; nearly all aerobic; all Gram-negative ex: Halococcus – Methanogens – anaerobic methane producers; use carbon dioxide; live in soil, swamps, digestive tracts ex: Methanococcus

Genetic variation in bacteria Mutations – bacteria can reproduce every 20 minutes binary fission – error rate in copying DNA 1 in every 200 bacteria has a mutation Genetic recombination – bacteria swap genes plasmids – small supplemental circles of DNA

Prokaryotic metabolism How do bacteria acquire their energy & nutrients? – photoautotrophs photosynthetic bacteria – chemoautotrophs oxidize inorganic compounds – nitrogen, sulfur, hydrogen… – heterotrophs live on plant & animal matter decomposers & pathogens

Genetic Recombination Type Source of New genesEntry method TransformationDNA in surroundingsEndocytosis TransductionVirus w/bacterial DNAViral mediated entry ConjugationOther bacteriaPili bridge cepts1.html hill.com/sites/ /student_view0/chapter13/animation_quiz_2. html

Prokaryote Cell Wall Structure peptide side chains cell wall peptidoglycan plasma membrane protein Gram-positive bacteria Gram-negative bacteria peptidoglycan plasma membrane outer membrane outer membrane of lipopolysaccharides cell wall peptidoglycan = polysaccharides + amino acid chains lipopolysaccharides = lipids + polysaccharides That’s important for your doctor to know!

Variations in Cell Interior aerobic bacterium cyanobacterium (photosythetic) bacterium internal membranes for photosynthesis like a chloroplast (thylakoids) internal membranes for respiration like a mitochondrion (cristae)

Bacteria as pathogens Disease-causing microbes plant diseases wilts, fruit rot, blights animal diseases tooth decay, ulcers anthrax, botulism plague, leprosy, “flesh- eating” disease STDs: gonorrhea, chlamydia typhoid, cholera TB, pneumonia lyme disease

Do you recognize…?

Bacteria as beneficial (& necessary) Life on Earth is dependent on bacteria – decomposers recycling of nutrients from dead to living – nitrogen fixation only organisms that can fix N from atmosphere – needed for synthesis of proteins & nucleic acids – plant root nodules – help in digestion (E. coli) digest cellulose for herbivores – cellulase enzyme produce vitamins K & B 12 for humans – produce foods & medicines from yogurt to insulin

Comparison of prokaryotes and eukaryotes… Describe three ways in which prokaryotes are similar to eukaryotes. Explain the size difference in prokaryotes and eukaryotes.

Prokaryotes and eukaryotes have three structures in common. Both have cell membranes that regulate what leaves and enters the cell. Ribosomes, which make proteins, are found in both types of cells. The cytoplasm, a fluid filled with ions and water, surrounds the internal structures in prokaryotes and eukaryotes. DNA is present in both cells however, in eukaryotes it is contained in a nucleus.

Eukaryotes are 10 times larger than prokaryotic cells. They have many internal compartments (organelles) that prokaryotes do not. The Theory of Endosymbiosis suggests that larger cells “ate” bacteria cells and didn’t digest them so they became larger.

Pathogenic Bacteria Name of bacteria Can you predict the shape from name? Gram-Stain (+ = purple, = pink) ShapeNotes