Ii enzymes are synthesized and formed as inactive

This preview shows page 8 - 11 out of 13 pages.

ii.Enzymes are synthesized and formed as inactive forms zymogensCells & OrganellesI.Origin of first cellsa.Involved 4 phases:i.Abiotic SYNTHESIS of simple organic compounds1.Stanley Miller Expii.Abiotic POLYMERIZATION of these into macromoleculesiii.Emergence of a macromolecule capable of REPLICATION & storing GENETIC INFOiv.Encapsulation of first living molecule within a simple MEMBRANEII.RNA before DNAa.RNAs such as ribozymes are capable of performing certain enzymatic rxns aka formation of peptide bonds during translation!b.Primordial lipids might have come together in an early ocean trapping RNA’s & forming first “protocells”III.Properties of Cells
a.As cells divide, the volume remains the SAME, but surface area INCREASESb.As cell size INCREASES i.Molecular concentration fallsii.Reaction rates slow downIV.Eukaryotic Strategies a.Use vesiclesto move molecules thru the cell that are transported along protein fibersb.Internal organellesallow localized concentration of molecules for a particular cellular functionc.Exocytosis= contents inside a vacuole are released to the outside of the cell thru fusion of the vacuole with the memd.Endocytosis = part of mem cleavages together to bring contents that are outside the cell into the cellV.Mitochondria, Chloroplast, & bacterial cellsa.Circular DNA WITHOUT histonesi.Synthesize ownRNA & proteinsb.rRNA seq., ribosome size, sensitivities to inhibitors of RNA & protein syn., & type of protein factors used in protein syn. c.Surrounded by DOUBLE membranes!i.Inner: bacterial-like lipidsii.Outer: eukaryotic lipidsVI.Endosymbiont Theory a.A protoeukaryotic cell engulfs an oxygen-utilizing bacterium (mitochondria) which then propagates independently inside of cellb.A descendant of this cell engulfs a photosynthetic bacterium (chloroplast) which also propagates independently inside of the cellVII.Endomembrane system a.Synthesizes proteins destined for organelles, cell mems, or secretion b.Transported in mem-bound vesiclesc.Organelles includei.ER (smooth & rough)ii.Golgiiii.Lysosomes = recycling toxic intermediatesVIII.ERa.Ribosomes on the ER help to synthesize secreted proteinsb.Free ribosomes synthesize cytoplasmic proteinsIX.Golgia.Process of glycosylation of proteins occurs in Golgi!!!b.Has vesicles transport proteins from golgi to plasma memX.Lysosomesa.Breaks down products to use to for later use or energy XI.Peroxisome a.Resemble lysosomes in size & appearanceb.H2O2 is highly toxic to cells, but can formed in H2O & O2 by catalase
c.Peroxisomes also oxidize long chain fatty acidsXII.Vacuoles a.Animal cells temporary storage or transport b.Plants cells have a central vacuole with high solute concentrations used to maintain pressure in cellsXIII.Ribosomes a.Site of protein synthesis & differ in each cell type (bacteria, archaea, eukarya)XIV.Extracellular Matrix & cell wallsa.ECM = give physical support to animal cells & consist of collagen fibrils & proteoglycansb.Plant cells contain cell walls for physical supportXV.Non-cellsa.Virus = infectious NA surrounded by a protein coatb.Viroid

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture