Lecture 31. Draw the structures of the Gram+ and Gram- cell envelopes and name the different elements of the envelopes 2. Compare and contrast the behaviors of Gram+ and Gram- bacteria in the Gram stain a. Gram Positive: i. Retains the crystal violet-iodine complexb. Gram Negative:i. Allows the crystal violet-iodine complex to diffuse out (stained Pink)3. List the major functions of the cytoplasmic membrane a. Permeability barrier- Prevents leakage, gateway for nutrients transport into and outof the cell.i. Semi-permeable: only some molecules (water, oxygen) pass through easily; passage of many nutrients requires energy.b. Anchor for proteins- For many proteins involved in transport (transport specificity) bioenergetics, and chemotaxis.i. And enzymes for synthesis of cell envelopec. Energy Production- Site of generation and use of the PMF (ATP synthesis)4. Name the components of the cytoplasmic membrane a. Phopholipid bilayer:i. (a) ester linkage in bacteria and eukaryotesii. (b) ether linkage in archaeab. Membrane proteins: All can have different functionsi. Transmembrane proteins (T): span the entire lipid bilayerii. Outer face (OF): exposed to periplasmiii. Inner face (IF): exposed to cytoplasm c. Fluid membrane:i. Allows lateral movement of proteins5. Describe the composition of bacterial phospholipids and how they are organized in a membrane a. Amphipathic moleculesb. Polar group attached to the phosphate is variablec. Two fatty acids, variable in length and number of double bondsd. Nature of fatty acids affects properties of the lipid bilayere. Organization in a membrane:i. Polar head on the outsideii. D-glycerol in middleiii. Fatty acids on insideiv. 2 goings both up and down6. Explain how the CM composition helps it be a permeability barrier a. Prevents leakage, gateway for nutrients transport into and out of cell7. Explain how the CM composition helps with energy conservationa. Energy production -- site of generation and use of the PMFi. ATP synthesis8. Compare and contrast passive diffusion into the cell and carrier- mediated transport a. Passive Diffusion: Only when external concentration is highb. Carrier mediated: Uptakes nutrients present at low external concentrationsc. Saturation effect d. Highly specific to one molecule or a small class of molecules9. Explain the saturation effect seen with carrier-mediated transporters a. Highly specific to one molecule or a small class of molecules10. Compare and contrast the three classes of transport systemsa. Simple transporter: single membrane proteini. Uniporter: Only one nutrient transported inii. Antiporter: External nutrient taken in while internal solute is taken outiii. Symporter: Two external solutes taken up simultaneously b. Group translocation: Series of proteins. Solute phosphorylated during transportc. ABC transporter: at least three proteins. Consumes ATP11. Describe how the glucose-specific phosphotransferase system works a. Solute phosphortlated when transported into the cellb. Several protiens involved; membrane bound (IIb and IIc), and cytoplasmicc. Source of energy is phosphoenolpyruvate (PEP)d. Generates glucose-6-P, which directly enters glycolysis12. Compare and contrast the specific- and non-specific components of the phosphotransferase system a. Specific: Enz IIa, IIb, and IIc are specific to glucoseb. Non-Specific: Enz I and HPr13. Describe how the ABC transporter for maltose works a. Maltose-specific porin in the OM: diffusion across the OMb. High- affinity periplasmic maltose-binding proteinc. Membrane-spanning transporterd. ATP-binding protein: energy to open a transient channel in the membrane proteine. *Highly specific solute-binding protein*14. Compare and contrast phosphotransferase system and ABC transporta. Phosphotransferaseb. ABC Transporti. Highly specific solute-binding proteinii. Energy from ATP drives
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