MCB 2004 - Lecture notes Quiz 1 notes PDF

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MCB 2004 Quiz One Study Guide (Lecture 1-3, Chapters 1-2)

Lecture One

1. Microbes: minute living creatures that cannot be seen with the unaided eye a. Includes: i. Bacteria ii. Fungi iii. Protozoa iv. Algae v. Viruses (noncellular) b. Jobs: i. Metabolize food ii. Grow iii. Reproduce c. Have sugars, proteins, nucleic acids, and lipids 2. Genome: an organism’s total genetic content a. Microbes have the greatest diversity of genomes (important concept for understanding evolution) 3. Conversions: a. Millimeters and micrometers (1 mm = 1000 micrometers) b. Micrometers and nanometers (1 micrometer = 1000 nanometers) 4. 6 major groups of microbes: a. Prokaryotes (no DNA in the nucleus) i. Bacteria ii. Archaea b. Eukaryotes i. Algae ii. Protozoa iii. Fungi (humans are most closely related to fungi) c. Viruses (noncellular) 5. Bacteria: (prokaryote) a. Have peptidoglycan cell walls b. Divide by binary fission c. For energy: i. Use organic chemicals, inorganic chemicals, or photosynthesis d. Many swim using flagella e. Many harmful bacteria, but also many beneficial bacteria f. Difficult to classify i. Hard to distinguish based on shape ii. Often reproduce asexually

iii. Pass DNA to each other without reproduction g. Ways to classify: i. Use biochemical properties: 1. Gram stain 2. Ability to metabolize different substrates ii. Use “immunoassays”: 1. Binding of test antibodies to different strains can detect different strains iii. Use DNA sequence: 1. Bacterial genomes = small iv. Nomenclature: naming the classified groups 1. Genus, species (Latinized and should be written in italics) a. Ex. Escherichia coli (named for Theodor Escherich and its habitat – the colon) 6. Archaea (prokaryote) a. Lack peptidoglycan cell walls – many types don’t have cell walls b. Live in extreme environments – have adapted very well to these environments c. Include: i. Methanogens ii. Extreme halophiles (high [ ] of salt) iii. Extreme thermophiles (live in hot, sulfurous water) d. NOT BACTERIA i. Similar size & shape ii. VERY different biochemistry 1. Different membranes 2. Archaeal ribosomes = similar to eukaryotic ribosomes e. 16s rRNA gene sequence i. Found in all creatures ii. Separate domain of life 7. Fungi (eukaryote) a. Chitin cell walls (chitin is in insect skeletons = very inflammatory) b. Use organic chemicals for energy c. Molds and mushrooms are multicellular i. Molds = most typical type of fungi ii. Molds form visible masses called mycelia 1. Mycelia are composed of long filaments that branch & intertwine called hyphae d. Yeasts are unicellular (larger than bacteria) e. Can reproduce sexually or asexually f. Obtain nourishment by absorbing organic material from their environment g. Many harmful fungi but also beneficial fungi 8. Protozoa (eukaryote) a. Absorb or ingest organic chemicals (parasites – derive nutrients from living hosts) b. Can move via pseudopods, cilia, or flagella c. Many beneficial protozoa in the environment – consume waste

d. Also harmful protozoa i. Plasmodium (malaria) ii. Naegleria fowleri 9. Algae (eukaryote) a. Ancestor of plants b. Cellulose cell walls c. Use photosynthesis for energy d. Produce O2 and organic compounds e. Help keep atmospheric gases in balance by consuming CO2 and producing O2 f. “True algae” are beneficial g. “Secondary endosymbiotic algae” can be very dangerous (ex. dinoflagellates like Karenia brevis = red tide) i. Endosymbiont theory 1. Mitochondria WERE bacteria 2. Chloroplasts were cyanobacteria 3. Infected or eaten by other species 4. Ended up living together inside (endosymbiosis) 10. Viruses (acellular – not complete cells like bacteria or other organisms – fundamentally different) a. *most know which diseases are caused by a virus, which diseases are caused by bacteria, etc. b. DNA or RNA genome c. Genome is surrounded by a protein called capsid i. This coat may be enclosed in a lipid envelope d. Viruses are replicated only when they are in a living host cell (intracellular parasites) e. Viruses are now being used to: i. Deliver vaccines and gene therapy (finding a beneficial use for viruses) 11. Multicellular animal parasites: (eukaryotes) a. 2 major groups of parasitic worms: i. Flatworms & roundworms  collectively known as helminths 1. During some stages, helminths are microscopic in size

Lecture Two

1. The Scientific Method: a. Assemble known information about a phenomenon b. Formulate a hypothesis to explain the phenomenon c. Design and perform experiments to test the hypothesis d. Analyze the data from the experiments and accept, reject, or revise the hypothesis i. DON’T just restate what you expected to happen. State what ACTUALLY happened in your experiment e. Repeat steps A-D

2. Discovery of microbes – 1st observations a. 1665: Robert Hooke reported that living things are composed or little boxes or “cells” i. This discovery marked the beginning of cell theory: all living things are composed of cells b. The first microbes were discovered by Anton van Leeuwenhoek (1673-1723) i. He wrote of the “animalcules” that he saw through a simple, single-lens magnifying lenses 3. Debate over spontaneous generation a. Spontaneous generation: the hypothesis that life arises from nonliving matter; a “vital force” is necessary for life b. Biogenesis: the hypothesis that living cells arise ONLY from preexisting living cells c. 1668: Francesco Redi filled jars with decaying meat to test the hypothesis of spontaneous generation of maggots & flies (disproved spontaneous generation for animals) i. Jars covered w fine net  no maggots ii. Open jars  maggots iii. Sealed jars  no maggots d. Many believed that germs were a special case and could spontaneously generate i. 1745: John Needham boiled nutrient broth and then put it into covered flasks 1. Nutrient broth heated, then placed in covered flask  microbial growth ii. Improved experimental design 1765: Lazzaro Spallanzani boiled nutrient solution in sealed flasks 1. Nutrient broth placed in flask, sealed, and then heated  no microbial growth 2. Appeared to disprove SG for germs 3. 1858: Rudolf Virchow further developed the biogenesis hypothesis by proposing that all cells arise from preexisting cells 4....