Biology Lecture 9b and c 10616 Chemotaxis runs and tumbles Lengthy runs and few tumbles in presence of attractants Short runs and many tumbles in absence of attractants Parent to offspring DNA vertical Pilus horizontallateral Click on link in slides to understand short pili Capsule limits loss of water in bacteria (slimy covering, JellOlike consistency) Viruses Outer protein sheath encloses genetic material called a capsid o Sometimes repeating units of proteins In animal viruses an additional envelope surrounds the capsid Lytic Cycle Virus replicates, makes protein coat, packages itself and ruptures cell Lysogenic Virus releases its DNA into host and it integrates into the host chromosome Bacteria becomes infected by bacteriophages and becomes virulent Hydrolysis waterbreaking breaks macromolecules into monomers Strategies to protect prokaryote cell contents from hydrolysis: 1. Limit enzymes to a certain target molecule, e.g. protein or carbohydrate a. Lipases (lipids) b. Proteases c. Sucrase 2. Limit occurrence in time of these types of reactions 3. Keep hydrolytic sites inside of a larger globular molecule Eukaryotes create compartments as protection 1. Hydrolysis andor breakdown of macromolecules or toxin Autophagy selfeating Lysosomes filled with digestive enzymes Fuel or old cells parts taken up by process of phagocytosis in lysosomes These are active transport mechanisms o Endocytosis, exo, pino, phago, etc.