List four different classes of eukaryotic cells Fungi food from other organisms cell walls filamentous growth Yeast unicellular budding reproduction Protozoa unicellular mostly motile can live in host Algae unicellular or multi photosynthetic simple reproductive system plants animals protists unicellular algae fungi What are some of the common features of eukaryotic cells What about prokaryotic cells Eukaryotes membrane enclosed organelles nucleus linear DNA w histone proteins 80S ribosome actin cytoskeleton Prokaryotes no membrane enclosed organelles nucleoid cell wall peptidoglycan circular DNA w o histone proteins 70S ribosomes Describe the structure and composition of a retrovirus Ex HIV Retrovirus exists as single stranded RNA packed into a capsid protein reverse transcriptase viral RNA is inserted and converted into double strand DNA integrase works like cut and paste transposon integrating the DNA into the host takes doubles strand DNA through nuclear pore because it contains the necessary nuclear localization signal integrase cuts 1 chromosome of cell and insert viral DNA into chromosome and re ligate it Then 3 different genes gag Pol ENV can be transcribed translated Outline the replication cycle of a retrovirus such as the Rous Sarcoma Virus gag polyprotein gets cleaved into different structural proteins capsid matrix nucleocapsid Pol cleaved into four parts viral integrase protease polymerase 2 fragments 2 polymeras reverse transciptase and RNase ENV codes for the envelope protein cleaved into 2 fragments of protein What are the major protein products encoded by the genome of a typical retrovirus and the functions of the proteins in the life cycle of the virus Capsid protein Reverse transcriptase Envelope protein Integrase requires 4 5 specific nucleotides for insertion takes the double stranded DNA through the nuclear pore using NUCLEAR LOCALIZATION SIGNAL cuts 1 chromosomes of cell and insets viral DNA into chromosome and religates it shuttle protein uses GTP to move integrase across the envelope Protease cleaves gag Pol and ENV by doing this makes it infectious Reverse Transcriptase makes DNA RNA and then DNA DNA double helix RNase dissolves RNA once it has been replicated Discuss the rationales behind the mechanisms of action of drugs either available or in development meant to block the entry of HIV into macrophages Inhibitors of reverse transcriptase integrase protease Summarize the roles and steps of HIV gp120 and of gp41 in membrane fusion How was it discovered that a deletion in the CCR5 gene could affect HIV tropism Env gene product is gp160 which is cleaved into gp120 and gp41 3 gp120s and gp41s combine in a trimer of heterodimers to form the envelope spike which mediates attachment to and entry into the host cell Gp120 glycoprotein on HIV envelope plays vital role in attachment to specific cell surface receptors CD4 receptor binding to CD4 induces changes in gp120 and gp41 that lead to fusion of the viral with the host membrane CCR5 protein on white blood cells receptor for chemokines how helper T cells are attracted to specific tissues HIV uses CCR5 to enter and infect host cells coreceptor by which HIV infects cells Tropism the way in which different viruses have evolved to preferentially target specific hosts How might a cell biologist use the life cycle of a given retrovirus to study mechanisms responsible for protein targeting and sorting in eukaryotic cells Discuss which aspects of the study of retroviral life cycles directly contributed to the development of recombinant DNA technology Using the reverse transcriptase in PCR to form new strands of DNA Suggest a procedure for how a genetically modified retrovirus might be used as a gene delivery vehicle in gene therapy take out the DNA RNA in the retrovirus that codes for any proteins that cause adverse effects Then replace it with your gene of interest And then you introduce the retrovirus into the organism With one sentence indicate the contributions to cell biology by each of the following individuals Robert Hooke development of compound microscope coined the term cell observed cork Anton Van Leeuwenhoek first to observe single celled organisms with a microscope beasties saw fungi protozoa algae bacteria archaea but not viruses Peyton Rous discovery of the role of viruses in cancer Rous Sarcoma Virus Irving Langmuir generated Langmuir trough made device to make measurements Gortel and Grendel first to propose membranes were composed of lipid bilayers Davson Davson proposed a cell membrane model that depicted the phospholipid bilayer sandwiched between two layers of globular proteins Danielli Singer membrane consisted of lipid bilayer covered in globular proteins Nicolson Linus Pauling identified what holds proteins together Review the general structural features and compositions of T4 phage tobacco mosaic virus adenovirus and the Rous Sarcoma Virus tobacco mosaic virus has capsid about 6400 RNA bases adenovirus double stranded DNA no reverse transcriptase capsid protein cover surface of virus responsible for 10 childhood infections 20 faced surface T4 phage bacteriophage double stranded DNA genome Rous Sarcoma Virus retrovirus oncovirus What is meant by a unit membrane Give an illustration for how the membrane would look under the electron microscope What about under the light microscope unit membrane proteins are coating membrane on both sides What are the major constituents of biological membranes of eukaryotic cells constituents of membranes composition reflects functional difference 1 lipids 2 proteins 3 carbohydrates Give the structure and name of a saturated fatty acid Show the structure of the fatty acid when it is unsaturated octanoic acid What are the constituents of a phospholipid Fatty acid can be saturated of unsaturated Chain of carbon atoms Charged carboxylic group Glycerol 3 carbons and 3 O Phosphate group Charged polar molecular like choline Draw the structure and label the constituents of a phospholipid Define each of the following terms Amphipathic Hydrophobic Hydrophilic One end is water soluble the other is lipid soluble Hydrophilic charged end Hydrophobic uncharged end Draw the structure of cholesterol and indicate why the molecule is amphipathic Only in eukaryotes Rigid ring structure single hydroxyl group polar short hydrocarbon chain nonpolar How do we know that the plasma membranes of red blood cells consist of a bilayer of phospholipids Briefly outline the history behind
View Full Document
Unlocking...