larry m. frolich, ph.d. biology department, yavapai college cell diversity and photosynthesis...
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Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Cell Diversity and Photosynthesis
• Diversity of MetabolismsDiversity of Metabolisms
• PhotosynthesisPhotosynthesis
• Prokaryotic and Eukaryotic CellsProkaryotic and Eukaryotic Cells
• Prokaryotes—Archaea and BacteriaProkaryotes—Archaea and Bacteria
• Eukaryotes—Protists, Plants, Eukaryotes—Protists, Plants, Fungi, AnimalesFungi, Animales
• Viruses and PhagesViruses and Phages
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Basic metabolic requirements
• Energy to build carbon chains
• Oxygen…sometimes
• Nitrogen, Iron and other chemicals
• Physical environment
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Energy and Carbon sources
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Depending on carbon and energy source:
• Photoautotrophs: CO2, light
• Photoheterotrophs: organics, light
• Chemoautotrophs: CO2, chemical
• Chemoheterotrophs: organics, chemical
Thought question: Which is most common among macrobiological organisms? What are we?
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Photosynthesis overview
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Photosynthesis I. Light reaction(Photosystem I and II are part of this)
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Photosynthesis II. Calvin cycle
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Other chemical requirements
• Nitrogen: necessary component of amino acids and nucleotides, can be limiting, nitrogen-fixing bacteria (Rhizobium) very important in food chain
• Iron, may be limiting factor in bacterial survival (reading from “Why we get sick?”)
• Common ions: sodium, phosphorous, potassium, chlorine, magnesium, calcium
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Physical aspects of cell’s environment
• Temperature—how hot is it?
• pH—how acid is it?
• Water osmotic pressure—how salty is it?
• Water hydrostatic pressure—how deep is it?
• More on these factors in Unit III
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Overview of Diversity
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Prokaryotes—simple cells with no organelles
The primitive Archaea are frequently "extreme-o-philes," including these heat-tolerant forms that live in hot springs
Electron micrograph of rod-shaped bacteria--Bacillus?
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Prokaryotes—simple cell division, no chromosomes
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
• Typical shapes of prokaryotic cells
• Cells are tiny—as small as 1 micron
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Archaea• Archaea are a group of
bacteria-like prokaryotes that are believed to be very close to the root of the tree of life
• Characteristics of Archaea (different from bacteria): – Lack peptidoglycan in cell
wall – Cell membrane lipids with
branched hydrocarbon chains
– AUG start codon for protein precursor is methionine (like eukaryotes) and not N-formylmethionine (like bacteria) Archaea in solar evaporation ponds near San Francisco
Bay--often have red or orange pigment to protect them from intense solar energy
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Principally "extremophiles“– live in harsh
environments: – Thermophiles – Halophiles--highly saline
habitats like Dead Sea, Great Salt Lake and solar evaporation ponds for salt production
– Methanogens--obligate anaerobes in high methane environments--deep sea vents, colons of animals, sewage treatment plants
Archaea
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Bacteria Cell Shapes and Groupings
Bacilli—ball-shaped bacteria
Cocci—rod-shaped bacteria
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
• Lots of bacterial groups!! Lots of bacteria!!
• closeness of disks shows similarity of rRNA sequence
See course website for link to images, descriptions of bacterial groups
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Eukaryotes
• Ciliates• Have cilia
around cell to propel and encounter environment
• Paramecium being devoured by Didinium (at right)
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
• Apicomplexans
• All pathogens of animals
• Includes Plasmodium--protozoan that causes malaria (life cycle at right)
Eukaryotes
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
• Dinoflagellates• photosynthetic
using carotene and chlorophylss
• make up large part of freshwater and marine plankton
• Often have protective "skeleton" of silica (at right) that frequently forms fossils
• Many are bioluminescent
• Some produce neurotoxins that can poison fish are people who handle infected fish
Eukaryotes
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
• Amoebae• not clear where
amoebae belong in taxonomic scheme or if they are all related
• all feed and move with pseudopodia
• lack mitochondria • include
Radiolarians and foraminifera (planktonic forms with silica and calcium carbonate armor)
• At right is typical amoeba and Radiolarian
Eukaryotes
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
• Euglenozoa• have
choloroplasts • lack cell walls
and have flagella • plant allies or
animal allies--own kingdom??
• Euglena, at right, is classic example
Eukaryotes
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
• Soil decomposers • Mycorrhizae--fungal filaments on roots of plants (90% of plants have
them) help to absorb minerals and water • Nutritious food source--mushrooms • Important spiritual source--hallucinogenic forms • Produce antibiotics (penicillin, etc.) • Food preparation--bread, alcohol, citric acid for soft drinks and other
prepared drinks) • All fungi reproduce by cell division or asexually • Almost all have sexual reproduction by budding, asexual spores or
sexual spores on thalli or fruiting bodies (large mushrooms are example) • Basidiomycota is mushroom group • Ascomycota is mold and yeast group • Zygomycota is small, mostly parasitic group, also includes some molds
Eukaryotes-- Fungi
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Penicillin with asexual spores at ends
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
• symbiotic fungus and cyanobacteria growing together
• sometimes algae replaces cyanobacteria
• sometimes not symbiotic in that fungus kills photosynthetic component
• important soil forming organism--break down new rock
• good air quality indicators--do not grow in polluted environment
Eukaryotes-- Lichens
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
• Seaweed is multicellular algae--most seaweeds have single-cell part of life cycle
• Many algaes only live as single-celled form
• Important component of marine plankton, especially diatoms
• Several groups of algaes--green algae, red algae, yellow, golden and diatoms, brown algae
• Diatoms have cell walls, composed of silica and cellulose--the silica often fossilizes and forms huge diatomaceous deposits much sought-after by gardeners for their high silica content and light weight porous nature
Eukaryotes-- Algae
Diatom frustrules (two halves fit together like petri dish)
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
• Previously grouped with fungi, but significant differences
• Water molds decompose dead animals in aqueous environment, also parasitic forms--Irish Potato famine caused by Phytophthora or late blight, still most damaging potato crop disease to this day.
• Slime molds may represent early forms of sexual reproduction--complex life cycle with large multi-nucleated, mobile (in amoeba-like form), synchtiums.
Eukaryotes– Water Molds and Slime Molds
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Viruses and Phages
• All are obligatory intracellular parasites--need to be inside a prokaryotic or eukaryotic cell to reproduce
• Viruses infect eukaryotic cells; phages infect prokaryotic cells
• Virus particles, when outside of cells, cannot be seen in light microscope--size is 10-300 nm
• Particle consists of nucleic acids surrounded by one or two protein coats and sometimes protein appendage
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
Viruses and Phages
Viruses reproduce by making copies of proteins and nucleic acids inside host celll
Larry M. Frolich, Ph.D.Biology Department, Yavapai College
• Viruses are characterized and grouped according to what kind of nucleic acids are found in the particles, and therefore how they reproduce themselves within cells. RNA viruses require reverse transcriptase (to go from RNA to DNA) which has been very important in genetic engineering:
• viruses types are dsDNA, ssDNA, ssRNA, dsRNA, retroviruses (ds=double-stranded; ss=single-stranded)
• Viruses do not all causes infectious diseases and may be involved in normal development or secondary factors in cancers, diabetes and other conditions
• Viroids are small circular pieces of RNA without any protein capsid that infect plants
• Prions ("PROteinaceous INfective agents) are proteins that can convert cells into a disease state
Viruses and Phages