BIO 326R 1st Edition Lecture 2Outline of Last Lecture I. Earth Historya. Earth formsi. Meteorites1. Isotope ratiosb. Life beginsi. Fossil records1. Stromatolites2. C12/C13 ratiosc. Great Oxidation Eventd. Evolution of eukaryotese. Animals arrivedf. Homosapiens arrivedII. History of Microbiologya. Leuwenhoeki. Bacteria under a microscopeb. Pasteuri. Swan neck flask1. Spontaneous generationc. RediOutline of Current Lecture I. Phylogenetic Treea. Bacteriab. Archaeac. EukaryeaII. Bacteria traitsa. Sizei. ShapeThese 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.ii. Surface areaiii. Doubling timeb. Volumec. ProteinIII. Bacterial Cell Structurea. Cytoplasmi. Cytosol1. Ribosomes2. Nucleoid3. Ionsii. Viscosityb. Cell membranei. Phospholipid membrane1. Phospholipid structure2. Function of membranea. Permeability3. Sterol-lite moleculesa. Fluidityii. Protection1. Gram negative2. Gram positiveCurrent Lecture- Phylogenetic Tree: Three Domains of Lifeo Bacteria, archaea, eukarea Previously, bacteria and archaea were lumped together, but they are very different Archaea and eukaryotes share similar methods of transcription Some eukaryotes are microbes- Microbe= single celled with nucleuso Ex: parasites and fungi- Bacteriao Size Average: 1-4 microns- Largest: 750 micronso Thiomargaritao Epulopiscium Gives birth to offspringo Volume Average: 10^-15 literso Protein 2.5 million needed to make bacteriao Benefit to being small? Shape- Cocci, bacilli, spiralo Cocci volume ratio: SA/V= 3/r Smaller radius scales to larger ratio or surface area Surface area- Bacteria grow by absorbing and diffusing nutrients from outside Doubling time- 9-10 minutes in clostridum- 25-30 minutes in E. Colio Bacterial Cell Structure Cytoplasm= intracellular milieu contained within the cell membrane- Cytosol= liquid portion of cytoplasmo 80% watero Ribosomes Clustered in cytosolo Nucleoid= where DNA is stored Chromosome of E. Coli is 1000 times longer than the cell Purified DNA diluted 1/10 is a gel- In most bacteria, but not E. Colio Ions Exist in a high concentration in water- 300 microns 250 microns potassium 1 micron glucose- Viscosity of cytoplasmo Measured by rate of diffusion The longer diffusion takes, the more viscous the cytoplasmo .00-800 times slower than water 10 times slower in eukaryoteso Bacteria viscosity is between olive oil and glycerin Cell membrane- Phospholipid membraneo 8nm thicko Van der waals interaction between hydrophobic regions of phospholipids, no watero Hydrophilic region on outside, towards water - 50-70% membrane is protein- Permeabilityo Small, uncharged molecules, gases (O2) can pass freelyo Glucose, amino acids, ions, other large or charged molecules require transporters Transport proteins are highly specific and span the membrane- Fluid mosaic modelo Membrane is not statico Proteins and phospholipids move around- Functiono Permeability barriero Proton motive force Establishes a gradient to do worko Protection Bacteria live as a single cell alone Gram negative and gram positive- Viscosityo Viscous as olive oil- Sterol-lite molecules= hopenoidso Cholesterol-like molecules that, like cholesterol, control fluidityo Low temperature, less fluid, cell makes more hopenoids to keep
View Full Document
Unlocking...