1、,Archaea = microbes, often from extreme/ (”primordial”?) environments,Bacteria = microbes, including medically important bacteria; also mitochondria and chloroplasts,Eukarya unicellular and multicellular organisms,Universal phylogenetic tree,“Prokaryotes”: nucleus is not surrounded by a nuclear memb
2、rane,1-1,Ribosomes Supramolecular complexes of proteins and ribosomal RNAs = sites of protein synthesis,Structural features of E. coli (= bacterium),no nuclear membrane,1-2,- Bacteria and Archaea are commonly referred to as “prokaryotes” because they have no nuclear membrane, in contract to “eukaryo
3、tes”- Bacteria and Archaea are usually small cells (1-2 m in length), whereas eukaryotic cells are 4 (eg. yeast) to 100 m across- Bacteria and Archaea have no membrane-enclosed, intracellular compartments,(= complex of cross-linked polysaccharides and peptides, sometimes lipids and glycolipids),Cyto
4、plasm + soluble proteins and low mol. wt. compounds,Structural features of animal and plant cells (= eukaryotic cells),1-3,Chloroplast,Vacuole,How eukaryotic cells may have evolved,2. Development of system of intracellular membranes, including membrane surrounding DNA(nuclear membrane),1. Acquisitio
5、n of elaborate mechanisms to package DNA (complexes with proteins in chromosomes)and separate it between daughter cells at division (protein filaments of cytoskeleton),3. Endosymbiotic associations between aerobic and/or photosynthetic bacteria(chloroplasts and mitochondria),1-4,Subcellular fraction
6、ation of liver,Exploit the fact that different cellular components have different densities: sediment at different g forces,low suc,high suc,1-5,Structural hierarchy in the organization of cells,1-6,Dimeric protein binding DNA:,Structure of myoglobin:,Amino Acids and Proteins,Later, well discuss the
7、 forces that determine the 3-D structure a protein adopts: i) covalent bonds ii) many “weak” or non-covalentinteractions,1-7,Deoxyribonucleic acid (DNA),Sugar phosphate backbone,Double helix,The same sorts of “weak” or non-covalent interactions that determine protein structure also determinine the d
8、ouble helical structure of DNA (eg. hydrogen bonding),1-8,Lipid bilayer (=membrane) + integral membrane protein:,Membrane lipids,1-9,Polysaccharides,Glycogen (storage),Chitin (structural),1-10,Building blocks,4 deoxyribonucleotides,20 amino acids,4 ribonucleotides,sugars,6-8 fatty acids,eg. Na, K, Ca, Cl, Mg, Fe, Mn, Co, Cu, Zn, I, Se,Mol. wt. range of proteins in cells 10,000-200,000,1-11,Inside an E. coli cell,1-12,
