Exam 2 Notes 1 Other biological entities 2 Viruses non living entities a Viroids i Even simpler and smaller than viruses ii Fragments of single stranded RNA with NO protein coat iii Hijack cells infects plant cells including citrus trees potatoes and avocados b Prions i Unusual infectious particles ii Protein particle with no genetic material DNA or RNA iii Mad cow disease Creutzfeldt Jakob disease and kuru iv Prions consist of a protein that is folded incorrectly and makes other proteins fold wrong v Origin Developed as a by product of living organisms 3 Prokaryotes all prokaryotes are microbes a Bacteria and Archaea domains b 12 000 species described may be 100 1000x that number c 1st organism to appear on earth 3 5 billion years ago d Common characteristics i Cell wall semi rigid permeable made of peptidoglycan carbohydrate with amino acids attached Gives bacteria shapes Animals don t have cell walls around their cells have cell membrane but bacteria and archaea do ii Shapes 1 Bacilli rod shaped 2 Cocci sphere shaped iii Capsules and slime layers 1 Capsule highly organized firmly attached to cell wall 2 Slime layer less organized loosely attached to cell wall a These structures help the cells retain water and stay alive b Help them attach to where they are 3 Pili hair like structures on surface of bacteria which aid in attachment to substrate 4 Rotating flagella a 50 of bacterial species are motile b Flagella are used to locomotion iv Taxis means bacteria is moving 1 Positive taxis moves towards something 2 Negative taxis swims away from something 3 Positive chemo taxis swims towards a beneficial chemical 4 Positive photo taxis swims towards light 5 Negative photo taxis swims away from light v Endospore Protective resting structures bacteria surrounded by durable cell wall Resistant to extreme conditions vi Reproduction 1 Prokaryotes reproduce mostly asexually in the form of binary fission a Only eukaryotic cells go through mitosis and meiosis prokaryotes do not b Sexually in form of conjugation using sex pili to transfer 2 Prokaryotes generally have circular chromosomes eukaryotes have plasmids linear chromosomes 3 Sexual in the form of conjugation using plasmids vii Energy sources 1 Autotrophs use photosynthesis or chemosynthesis energy from inorganic chemicals Bioremediation cleaning up mess 2 Heterotrophs including symbiotes viii How do prokaryotes affect other organisms 1 Prokaryotes capture the nitrogen needed by plants 2 Prokaryotes are nature s great recyclers a Bacteria and Eukarya Fungi ix Human Diseases Gonorrhea syphilis tuberculosis lyme disease x All are human pathogens disease causing xi Bacterial antibiotic resistance Chapter 22 The Fungi 1 Fungi is the kingdom that animals are most closely related to 2 Fungal Structures My Hot College Slut Self a Mycelium the feeding network of a fungus i The body of the fungus the actual mushroom ii May be very large iii Usually underground or inside a decaying or living organism iv Composed of a woven mesh of hyphae b Hyphae singular hypha i The threadlike filaments of a fungus ii Fungi have tubular cell walls that contains chitin iii Glucose and nitrogen iv Surrounds the plasma membrane and cytoplasm c Chitin d Septa e Spores i Structural polysaccharide of modified sugars ii Polymer with glucose subunits and N containing functional groups iii Makes up insect exoskeletons and fungus cell walls iv Wraps around individual cells in the fungus making them extremely strong i Structures which partially separate the cytoplasm inside the hyphae found in many fungi ii Allows controlled movement of materials from one cell to another iii Not all fungi have this structure i All fungi produce spores ii Haploid 1n or diploid 2n cells which can grow directly into a hyphal strand 1 Haploid one copy of each chromosome in the spore 2 Human sex cells are also haploid between 3 Fungus for most of its life is haploid its diploid phase is actually very short which is the opposite for animals iii There are no sexes with fungi instead there are mating types iv When mating type 1 and mating type 5 come together millions of offspring are created every baby spore that is created is different v Why bother with sexual reproduction For variation 3 Fungal lifestyles a Use absorption to obtain their food b Three variations depending on the food type i Saprobes decomposers of dead material most fungi feed on dead material ii Parasites fungi which grow on living organisms Dutch elm disease Corn smut Athletes foot Jock itch Yeast infections iii Mutualists fungi that live interdependently with photosynthetic organisms 1 Lichens symbiotic relationship between a fungal species and either a cyanobacteria or unicellular photosynthetic eukaryote Ex Algal layer fungal hyphae attachment structure a Cyanobacteria is a photosynthetic prokaryote b Obligate symbiotic relationship One cannot live without the other 2 Mycorrhizae a Symbiotic relationships between fungi and the roots of a plant i The majority of plants today have this relationship with fungus about 90 ii Fungi help send the plant water minerals and nutrients iii Some of the sugars the plant produces are absorbed by the fungus 4 Fungal divisions phyla a Over 100 000 fungal species identified and more are added each year b Five major divisions of the Kingdom Fungi c These divisions are based on DNA sequence data on the presence of septa in the fungi and on the sexual life cycle i Zygote fungi Division Zygomycota ii Named for the zygospore which has a thick cell wall 1 Fungal divisions a Phylum Chytrids i Ancient group diverged earliest from the other fungi ii Aquatic the only fungi with flagellated spores zoospores These spores can swim require water for them to move around iii Sparobic 1 Decompose dead material 2 Majority of them are saprobic iv Only some are parasitic b Phylum Zygote fungi i Sexual reproduction via zygosporangia resistant heterokaryons that produce 1 During sexual reproduction this fungus creates thick cells that are called ii Asexual reproduction via sporangia that produce spores iii Mostly saprobic decayers of organic matter e g soft fruit rot fungi and black genetically variable spores zygosporangium break mold iv Some are parasitic e g single celled microsporidia c Glomeromycota fungi that form myccorhizal associations specifically at their roots d Sac fungi Division Ascomycota i Sexual reproduction via spores produced in asci sac like cases 1 Spores produced are called asco spores 2
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