BIO 151 1st Edition Lecture 17 Outline of Last Lecture 1. Assume early cell has membrane DNA to RNA to protein2. Eukaryotes have membrane-bound "organelles"3. Evolution of eukaryotes4. Prokaryotes vs. eukaryotes5. Mitochondria6. Chloroplasts7. Endosymbiant8. Endocytosis9."Semi-autonomous" organelles10. Some cells have true bacterial endosymbionts11. Nucleus12. Protein import into nucleus13. Endomembrane system for secreted and transmembrane proteins, carbohydrates, lipids14. Endoplasmic Reticulum (ER)15. Smooth ER16. Rough ER17. "Processing" of proteins in ER and Golgi18. Vesicle formation and trafficking Outline of Current Lecture 1. Movement to and from ER and Golgi via transport and secretory vesicles2. "Trafficking" of vesicles3. Movement of vesicles - not simply diffusion4. Cytoskeleton in eukaryotes 5. Microtubules6. In animal cells, microtubules often emerge from pair of centrioles in centrosome7. Microfilaments8. Intermediate filaments9. Coat proteinsCurrent Lecture Movement to and from ER and Golgi via transport and secretory vesicles:- "trafficking" contents (proteins, carbohydrates, lipids) of endomembrane system- engineer DNA and insert gene to make normal secreted protein fused with fluorescent protein (from jellyfish or coral) visualize in living cell- movement of vesicles, tubules inside cell- secretion (movement of substance to outside) via exocytosis"Trafficking" of vesicles:- xxx-"somes"- ex. fuse endocytic vesicles (endosomes, phagosomes) with lysosomes that contain digestive enzymes- movement of vesicles to GolgiMovement of vesicles - not simply diffusion:These 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.- attached to elements of cytoskeleton = intracellular rods and fibers that support cell- moved by motor proteinsCytoskeleton in eukaryotes: - microtubules - thickest diameter- microfilaments - finest diameter- intermediate filaments - intermediate diameter- coat proteins - wrap and shape vesicles, tubesMicrotubules:- helical polymer made of individual dimers of alpha and beta tubulin proteins- can be stable "girders", but also move things- microtubules can...1) Push or pull things by rapid lengthening or shortening -microtubule assembly and disassembly - looking at engineered fluorescent tubulin-microtubules can also move things by...2) using attached motor proteins-ex. kinesin or dynein - "walk" vesicles along microtubule-different motor proteins can walk opposite directions along microtubule-microtubules can move things by...3) sliding past each other via motor proteins- sliding microtubules move by cilia and flagella- cilia, flagella - fine bendable projections from cell, enclosed by cell membrane- long, few = flagella- short, many = cilia- cilia and flagella - projections of cell membrane- contain microtubules organized into ring - 9 pairs in ring plus 2 central ("9+2")- pairs connected by dynein = motor protein- attempts to slide bends cilium/flagellumIn animal cells, microtubules often emerge from pair of centrioles in centrosome:- microtubule organizing center- 2 cylinders, each with a ring of 9 microtubule "triplets"- endosome is a membrane-wrapped vesicleMicrofilaments:- double helix made of actin proteins- movement -1) shortened or lengthened by removal or addition of actin2) slide past eachother using motor proteins = myosins-actin movements also drive actively changing extensions of cell membrane = "xxx-podia" (xxx-feet)-blobby = pseudopodia-fine = filopodia-flat = lamellipodia-actin also moves things inside cells:-ex. cytoplasmic streaming in plants-muscle contraction - use myosin motor proteins to slide microfilamentsIntermediate Filaments:- mostly structural - meshwork (red) just inside membranes, shape cellular organelles- many different types- same family as nuclear lamininCoat Proteins:- help shape and traffic membranes, vesicles =
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