Ch. 1

Ch. 1 Prokaryotes = bacteria , archaea Eukaryotes = Fungi, protozoa , algae (Growth:: Mitosis有絲分裂) Bacterial cell → Bacillus(rodlike) , cocus (spherical), spiral (curved) *P. S. 有時 會star-shaped or square → 出ç�¾æ—¢å½¢å¼�: pairs, chains, clusters cell walls of bacteria → peptidoglycan (carbohydrate & protein complex) cell walls of plant and algal cell → cellulose Growth:: Binary fission = bacteria reproduce by dividing into two equal cells bacteria å�¸æ”¶nutrients from dead / living organisms/ photosynthesis / inorganic substance 佢地å�¯ä»¥swim by moving flagella Archaea if 佢地有cell wall → lack peptidoglycan Found in extreme environments -Growth:: Binary fission -cell wall → peptidoglycan 分3 main groups → methanogens + extreme halophiles + extreme thermophiles Methanogens → produce methane Halophiles → live in extreme env. eg. The Dead Sea Thermophiles → live in hot sulfurous water eg. Hot springs at Yellowstone National Park Fungi Cells hv a district nucleus = DNA surrounded by special envelope(lipid membrane) = nuclear membrane unicellular(eg. yeast) / multicellular (eg. Mushrooms, molds) cell wall of true fungi →compose of chitin 最common fungi → molds(mycelia (bread & fruit) → compose of long hyphae) å�¸æ”¶nourishment by absorbing sol. of organic material from environment (eg. Soil , seawater)slime molds → æ“�有characteristics of both fungi & amoebas Protozoa -unicellular -move by pseudopods, flagella , cilia å�¸æ”¶nutrients from absorb or ingest organic compound *Euglena → photosynthetic, use light as source and carbon dioxide as chief source to produce sugars Amebae都係 move by using pseudopods Algae 好多shapes & sexually & asexual reproductive forms. -usually unicellular -rich in freshwater, salt water, soil, association wif plants -photosynthesis for food production & growth -no need organic compounds -Produce oxygen & carbohydrates for other organisms(eg. Animal) Viruses -so small (diff. From the aboves) -acellular (nt cellular) -only one type of nucleic acid (DNA/RNA) -st encase by envelope -reproduce by using the cellular machinery of other organisms. -parasites of other forms of life (é� å…¶ä»–ç” Ÿå‘½ç” Ÿå­˜like 寄 ç” ŸèŸ²) Multicellular Animal Parasites -eukaryotes -eg. helminths(蠕蟲) Genetics info. In a cell = genome Chomosomes contains DNA(genes) Genes = segment of DNA Genotype & Phenotype G. = inheritable info. (å�¯ç¹¼æ‰¿çš„) P. = å�—G. 影嚮而表ç�¾å‡ºä¾†, eg. Blood, height, iq, color of eye Ch. 10 Three domain: eukaryotes + prokaryotes (bacteria, archaea)-Each domain shares genes wif other domains eg. Thermotogaä¿‚ 從an archaeonæ¼” 變的 -Kingdom → Phylum → class → order → family → Genus → species *Classification is base on similarity in nucleotide sequence in rRNAProkaryotes vs Virus:::-Virus cannot survive independently.-Virus ä¾�è³´host cell Ch. 4 After dividing, Cocci → pairs = diplococci → chainlike = streptococci → groups of four = tetrads → groups of eight = sarcine → grapelike clusters = staphylococci Bacilli → single = single bacillus → pairs = diplobacilli → chains = streptobacilli → oval, like cocci = coccobacilli Spiral → curved = vibrios → helical shape, rigid = spirillum → helical shape, flexible = spirochete External of cell wall -Glycocalyx (gelatinous polysaccharide & / polypetide covering) → Capsule = the substance is organized & is firmly attached to the cell wall (*protect pathogens from phagocytosis & prevent desiccation) → Slime layer = .. unorganized & only loosely attacted. → Extracellular polysaccharide -Flagella → rotate to push the cell → +ve taxis(movement of bacterium) moves towards an attractant, -ve taxis moves away from a repellent -Axial Filaments → spiral cells tht move by spirochetes → similar to flagella, diff. : it wrap around the cell (包ä½�) -Fimbriae and pili → help cells adhere to surfaces → pili are involved in DNA transfer & twiching motility Cell wall -prevent bacterial cells from rupturing when the water pressure inside the cell > outside the cell -maintains shape of bacterium -serves as a pt of anchorage for flagella Peptidoglycan -disaccharide (NAG + NAM)+ polypeptide Diff. Between Gram +ve & Gram-ve cell wall- -ve 有outer membrane 先到peptidoglycan å†�到plasma membrane while +ve 直接pep. 包ä½�plasma membrane- -ve æ—¢ peptidoglycan → thin- +ve contains teichoic acids while -ve dun hv- +ve produce exotoxins; -ve produce exo. +endotoxin- +ve 2 rings basal body ~ -ve 4 rings *prokaryotic plasma membrane less rigid than eukaryotic ,, . cuz lack of sterols (except Mycoplasma (prokar.) which has sterols) cytoplasm ä¿‚ plasma membraneå…¥é�¢ Nucleoid ï¼� bacterial chromosome Ribosome = protein synthesis (越high rate, 越large no. of ribosome) *prokaryotic ribosome smaller & less dense (70S ribosomes); eukaryotic cells (80S) Endospores (cells) 呢個é�Žç¨‹å�« sporogenesis 1)Spore septum begins to isolate newly replicated DNA & a small portion of cytoplasm 2)Plasma membrane starts to surround DNA, cytoplasm, & membrane isolated in step 1. 3)Spore septum surrounds isolated portion, forming forespore. 4)peptidoglycan layer forms between membranes 5)spore coat forms 6)Endospore is freed from cell. Flagella & cilia (細胞é�¢d毛毛)-flagella → few & long -cilia → short & numerous Nuclear envelopeä¿‚ 包ä½�nucleusæ—¢membrane Nuclear envelope 附 è¿‘ 個dä¿‚ endoplasmic reticulum(ER) Ch. 5 Metabolism: sum of the Chemical rxn;;; ATP & oxygen required catabolism = release energy , breakdown of complex organic compound; hydrolytic rxn; exergonic anabolism = require energy , building of complex organic molecules; dehydration synthesis rxn; endergonicMetabolic pathway = sequence of enzymatically catalyzed chem. rxn in a cell;; determined by enzymes = encoded by genesFactors affecting enzyme activity: 1)Temp. → move faster = more energy ; best → optimal temp. cuz denaturation if too high 2)pH → optimum pH;; extreme change in pH = denaturation3)Substrate conc. → increase conc of substrate molecules = increase rate until enzyme mole. are filled = max. rate4)inhibitor Respiration 1)Aerobic respiration → the final electron acceptor in the e- transport chain is molecular O2 2)Anaerobic respirationm → ………. is usually an inorganic substance and not O2 Fermentation→ aerobic / anaerobic→ spoilage of food(general use)→ produce alcoholic beverages / acidic dairy productsScientific definition → release energy from oxidation of organic molecules; no need oxygen and use the krebs cycle ; the final electron acceptor is an organic molecule1)Alcohol fermentation → produce ethanol + CO22)Lactic acid fermentation → produce lactic acid*homolactic fermentation produces lactic acid only heterlactic fermentation produce lactic acid & other compoundsCh. 6 Microbial GrowthPhysical requirement: 1)Temp. → psychrophiles(cold-loving microbes) , mesophiles(moderate temp.), thermophiles(heat-loving) ; psychrotrophs → grow at 0 or 20-30degree → food spoilage2)pH → grow best in pH 6. 5-7. 5; molds & yeast grow abt pH5-6 ; acidophiles grow in acidic envir. 3)Osmotic pressure → hypertonic envir. = plasmolysis ; extreme / obligate halophiles = grow in high salt conc. ; facultative halophiles = no require high salt envir. But grow in salt conc. 2%Chemical requirements1)Carbon2)Nitrogen, sulfur, phosphorous3)Trace elements → find in tap water, even distilled water4)Oxygen5)Organic growth factor Culture media = any material prepared for the growth of bacteria in a lab. Culture = microbes that grow and multiply in or on a culture mediaAgar = solidifying agentObtaining pure cultures → streak plate methodPreserve microbes → by deep-freezing / freeze-dryingBacterial replication:: Binary fission1)parent cell enlarges2)Duplication its chromosome3)cell wall & plasma membrane begin to constrict4)Cross-wall forms, completely separating the two DNA copies; then cells separateGeneration = time required for a cell to divideMeasurement of microbial growth:: Plate counts(ï¼�用plate 去 é‡�度) → needs some times 24hrs or up ; too many colonies → inaccuraciesç‚ ºé�¿å…�too many, → serial dilutionPour plate , spread plate(better â†� avoid contact between cells & melted agar)Mutation(3types)1. Beneficial mutations2. Harmful mutations3. Silent mutationsPhysical / chemical agents = mutagensWays of bacteria acquire new genetic: 1. Lysogenic Conversion2. Transduction3. Transformation4. ConjugationA plasmid can integrate into the chromosome = episomePlasmid:: 1. Conjugative plasmid: Carries genes for sex pili & transfer of the plasmid2. Dissimilation plasmids: Encode enzymes for catabolism of unusual compounds3. Complex transposons carry other genes