BIOL 209 1st Edition Lecture 8Outline of Last Lecture I. Question/Answer’sII. Classes of Viral StructuresIII. Viral Genomes – Diverse Structures IV. Viral GrowthV. Viral ReplicationA. Steps1. Absorption – binding to cell surface receptors2. & 3. Entry/Uncoating4. Synthesis of viral components5. Assembly of new virus6. Release of virusOutline of Current Lecture I. Norovirus & Blood Type ConnectionA. Norovirus definitionB. Question/AnswerII. Viral LatencyIII. Microbial GrowthA. RequirementsB. Sources of NutrientsC. Question/AnswerIV. SaprobesV. Binary FissionVI. Bacterial GrowthA. Exponential growthB. Question/AnswerC. Phases of population growth1. Lag2. Exponential3. Stationary4. DeathD. Conditions Effecting GrowthCurrent LectureI. Norovirus & Blood Type ConnectionA. Norovirus: non-enveloped (“naked”) RNA virus that infects gut epithelial cells1. Cells express the same blood types as found on your red blood cellsThese 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.2. Virus binds to blood group antigensB. Question/Answer1. Question: What mechanism do you think Norovirus uses to enter your gut epithelial cells? Answer: EndocytosisII. Viral LatencyA. Some viruses have the option of persisting in a host cell (hanging out for a while) without killing it, but reactivate later onB. Some bacteriophages and retroviruses can integrate their genome into host genome and are replicated along with host genome1. Some herpes virus genomes replicate as extrachromosomal plasmid each time the host cell replicatesC. “Latency” can also refer to conditions where host immune system is able to control a pathogen infection, but not eliminate itIII. Microbial GrowthA. Requirements1. A source of Carbon (and other elements)2. Energy, in order to synthesize components necessary for growthB. Sources of Nutrients1. Different microbes use different nutrient sourcesa. Autotrophs use Carbon Dioxide as Carbon sourcesb. Heterotrophs use nutrients from other organisms as both energy and Carbon sourceC. Question/Answer1. Question: Which processes require energy for transport? Answer: Carrier mediated active transport, endocytosis, and group translocation (not facilitated diffusion)a. Nutrient acquisition through membrane transportersb. Facilitated diffusion: movement down a concentration gradient – doesn’t require energy for transportc. Active transport: requires energy to concentrate nutrientsIV. SaprobesA. Decomposers – live primarily on dead organisms1. Produce exozymes (secreted enzymes) to digest food outside cell and take up nutrients that are releasedV. Binary Fission A. How bacteria reproduce1. Requires coordinate cell growth and replication of the genome2. Septum formation segregates the new genomes into separate cells3. The position of the septum marks the division plateB. Bacterial cell ‘arrangements’ depend on continuing attachment of cells following division1. Shape of arrangement depends on whether the division plate changes between generationsVI. Bacterial GrowthA. Exponential growth – bacterial populations expand exponentiallyB. Question/Answer1. Question: What determines growth rate? Answer: Nutrient availability and tools to take advantage of itC. Phases of population growth1. Lag – adjusting metabolism, not yet dividing rapidly2. Exponential – maximum growth rate3. Stationary – depleted nutrients and increased presence of toxic products, reduced cell sizea. Toxins represent changes in environment4. Death – more cells dying than dividingD. Conditions Effecting Growth1. Changes in pH, temperature, osmolarity, salt content, oxygen availability2. Some conditions may prevent growth of certain speciesa. Species can be classified based on growth requirements- Obligate, facultative,