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BI270 CELL BIOLOGY Part IV
The CELL
and MEMBRANE-BOUND SYSTEMS
Membrane Variation a) function b) lipid:protein ratio c) phospholipid content SINGER & NICOLSONThe FLUID MOSAIC MODEL LIPID BILAYER (external hydrophilic and internal hydrophobic) PROTEINS: Integral vs. Peripheral proteins Glycoproteins, Glycolipids and the Glycocalyx See a Fluid Mosaic diagram FREEZE FRACTURE and FREEZE ETCHING GLYCEROL Liquid N2 COLD KNIFE CARBON REPLICA See an example of Freeze Fracfture here DEAMER & BRANTON
Þ FF studies prove
"speckles" are T.L. STECK Þ RBC membranes and PROTEIN ASYMMETRY van DEENEN et al. van DEENEN et al. Þ RBC membranes and PHOSPHOLIPID ASYMMETRY FRYE & EDIDIN Þ cell fusion and heterokaryons
NICOLSON Þ NETWORK PROTEINS, ECTO- and ENDOENZYMES
PASSIVE TRANSPORT (= simple diffusion) vs. FACILITATED DIFFUSION* and ACTIVE TRANSPORT* (ATP)
BULK TRANSPORT: EXOCYTOSIS (secretion, etc.) vs. ENDOCYTOSIS [ a) phagocytosis vs. b) pinocytosis ]
ENDOPLASMIC RETICULUM CYTOSOL vs. INTRACISTERNAL SPACE (cisternae) ROUGH E.R. with ribosomes attached synthesis of membrane and "packaged" proteins [PROOF = ??] KEITH PORTER – electron microscopy of rough ER See Rough ER: Rough ER 1 Rough ER 2 RER TEMs SMOOTH E.R. (no ribosomes)
HENKART et al. and control of Ca++ SARCOPLASMIC RETICULUM = nerve impulse into muscle tissue SECRETORY CELLS and E.R. (Neutra, LeBlond, et al.) See a SECRETORY CELL Diagram here See a SECRETORY CELL Photo here PROTEINS and the E.R . è HOW??Milstein et al. and Ab secretion Þ extra amino acids at N-terminal end (non-polar) BLOBEL, DOBBERSTEIN et al.
See the ER and Protein Synthesis HERE Wickner’s Post-translational Insertion (with ATP) PROTEIN MODIFICATION and the Vesicles and Exocytosis Shuttle Vesicles CHOs and Glycoproteins [PROOF????] ROTHMAN Þ cis and trans Golgi
NEUTRA & LeBLOND Þ Goblet Cells, GC and secretory activity See MANY Golgi images and processes HERE Lysosomes and HYDROLYTIC ENZYMES1° Lysosomes 2° Lysosomes = 1° + Phagosome AUTOPHAGIC vs. HETEROPHAGIC Residual Bodies Microbodies Peroxisomes (catalase, etc.)Glyoxosomes (Glyoxylate Pathway, etc.) Return to Top of Page
KAPLAN and LIGANDS è ??
PASTAN & WILLINGHAM -- The Receptosome
Find out more about RECEPTOR-MEDIATED ENDOCYTOSIS here
MICROFILAMENTS 7-9 nm. Movement & Support Actin Evolutionarily CONSERVED Actin-Binding proteins:
myosin + Ca++ Þ CONTRACTED MICROFILAMENT POISONS: cytochalasin B [INHIBIT] vs. phalloidin [LOCK] {AXONS, MICROVILLI, PSEUDOPODIA} è Cytoskeleton MITOTIC SPINDLE MICROTUBULES 24 nm Movement & Support Tubulin Þ a and b heterodimers Þ protofilaments Microtubule-associated Proteins [MAPs] Þ (variation via alternate splicing) MICROTUBULE POISONS: colchicine [INHIBIT] vs. Taxol [LOCK] centrioles (= Basal Bodies) flagella (= cilia) 9 + 2 arrangement and axoneme structure MITOTIC SPINDLE INTERMEDIATE FILAMENTS 10 nm Support only!! Various components (keratin, etc.) TONOFILAMENTS (in spot desmosomes)
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