MCB 100 1st Edition Lecture 2 Outline of Last Lecture I. Introducing the study of microbiology II. Organisms and their relative sizes Outline of Current Lecture I. Types of microorganisms II. Traits of living cells III. Major groups of microorganisms and their properties Current LectureI. Types of microorganismsA. Cellular organisms (alive)i. Prokaryotes (no nuclear membrane)ii. Eukaryotes (normal nucleus) B. Subcellular aggregates of molecules (alive?)i. Viruses, viroids, and prionsII. Traits of all living cells A. Able to grow and reproduce (can convert nonliving nutrients into living cytoplasm)B. Genetic material is DNAC. Metabolism (hundreds of controlled biochemical reactions that are catalyzed by enzymes)D. Able to make or acquire ATP (energy rich molecule)E. Able to synthesize proteins (this requires energy from ATP, ribosomes, mRNA, a set of tRNAs and 20 amino acids)F. Bound by an active cell membrane (a diffusion barrier)III. Major groups of microorganisms A. Bacteria i. Prokaryotic cells (no nucleus)ii. Cell walls (some) composed of peptidoglycan (polysaccharide)iii. Some are photosynthetic iv. Some can fix nitrogenv. Reproduce asexuallyvi. Wide variety of metabolic lifestylesvii. Many excrete enzymes to digest to complex moleculesThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.viii. Some cause human disease B. Archaeai. Prokaryotic cells (no nucleus)ii. Cell walls composed of protein or pseudopeptidoglycaniii. Wide variety of metabolic lifestyles iv. Some produce methane v. Some are extremophiles (hyperthermophiles) so can live in high saline/arsenic rich places like: Monolake in California, acidic hot springs inYellowstone, oxygen-depleted mud at the bottom of swamps vi. Reproduce asexually vii. Do not excrete enzymes to digest complex moleculesviii. Do not cause human diseaseix. RNA polymerase is similar to eukaryotic enzymesC. Fungi i. Eukaryotic cells ii. Cell wall composed of chitiniii. Not photosyntheticiv. Most prefer aerobic conditionsv. Nutrient molecules absorbed by osmosisvi. Both sexual and asexual reproductionvii. Most have mitochondria viii. Fungi include:1. Molda. Typically multicellular organismsb. Grow as long filaments that intertwinec. Reproduce by sexual and asexual spores (cells that producea new individual without fusing with another cell)2. Yeasta. Unicellular; typically oval to roundb. Reproduce asexually by budding (process where a daughter cell grows off the mother cell) D. Protozoai. Eukaryotic cells; single-celledii. No cell walliii. Not photosyntheticiv. Some absorb nutrient molecules by osmosis, others engulf food particles by phagocytosisv. Both sexual and asexual reproductionvi. Most have mitochondriavii. Most prefer aerobic conditionsviii. Locomotive structures:1. Pseudopods: extensions of a cell that flow in the direction of travel2. Cilia: numerous short protrusions of a cell; beat rhythmically to propel protozoan through its environment.3. Flagella: extensions of a cell but are fewer, longer, and more whip-like than cilia E. Algaei. Eukaryotic cells; unicellular/multicellularii. Most have cell walls composed of celluloseiii. Photosyntheticiv. Both sexual and asexual reproductionv. Most have mitochondriavi. Most prefer aerobic conditions vii. Produce oxygen and fix carbon dioxideviii. Large algae (seaweeds and kelps in world's oceans); unicellular algae (freshwater ponds, streams, lakes, oceans)F. Virusesi. Not cellularii. Smaller than the smallest cellsiii. No active cell membraneiv. No ribosomes etc. for protein synthesisv. No ATP generating metabolismvi. Must be inside host cell to reproduce vii. Genetic material can be DNA or RNA, ss or ds viii. Were not seen until electron microscopes were invented in 1932)ix. Viroids: infectious particles seen in plants, similar to RNA viruses, except they lack a capsidx. Prions: infectious particles that lack nucleic acid. They are altered forms of normal proteins that appear to be able to change normal proteins to an abnormal shape upon contact. The abnormal form of the protein is associated with disease. G. Parasitic worms are the largest organisms studied by
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