Zoology101: Animal BiologyLast Lecture Outline Lecture 7 1. Prokaryotic Cell Structure• Human Microbiome2. Intestinal Gut Microbiome• Mice3. Development (Structure)4. Protective Function• Quorem SensingCurrent Lecture 1. Archaea2. Eukaryotic Cells• Animal Cell3. Nuclear Components• Nucleous• Lamina4. Protein sorting/targeting 5. Intro to Endomembrane SystemArchaea• Found in diverse environments◦ Extremeophiles▪ Extreme halophiles: salt loving▪ Extreme Thermophiles: heat loving ▪ Menthanogens: methane producers (Oxygen free environment)◦ Share some traits with bacteria (unicellular); some with Eukaryotes (common ancestor)▪ Bacteria: no nucleus, circular chromosomes, cell wall (not peptidoglycan)▪ Eukaryotes: similar “machinery” for gene expression (ex Riobosomes) Eukaryotic Cells• Cells must constantly interact with their surrounding environment• volume increases more rapidly than surface area • As cell size increases, surface area/volume ratio decreases, leads to diffusion problems • Solutions ◦ A: Compartmentaliztion: organelles (membrane bound structure in cell) ◦ B: Cell Shape: thin, flat, folds Animal Cell• Organelles-> Phopholipid bilayer• Plasma membrane • Cystol (cytoplasm)• Ribosomes (cystol, endoplasmic reticulum, mitochondria)• nucleus: largest organelle, rNA, DNANuclear Components • Nucleus: Surrounded by double membrane (nuclear envelope• nuclear pore: Holes in nuclear envelope• Nuclear Lamina: organizes chromatin, helps nucleus maintain shape • Nucleosus: site of ribosome synthesis • Chromatin: DNA and associated proteins • Lamina◦ Maintain shape and organizes chromatin◦ composed of lamin proteins (intermediate filament)▪ Long stringy proteins ◦ How to determine function?▪ Use of model organisms and human genetic conditions◦ Mutant lamin → LETHAL → irregular shape of nucleus, defect in chromosome organization◦ knock out mice → missing lamin A protein → abnormal nucleus → muscular distropic mice◦ Hutchinson-Gilford Progeria Syndrome (premature aging) Protein Sorting/targeting • Biological mechanism by which protein are transported to appropriate destinations in the cell or outside of it◦ ALL PROTEINS START OFF BEING MADE BY RIBOSOME IN CYSTOL• Signal sequences (targeting signal)= cellular zipcode, information contained in polypeptide chain (amino acids)• Proteins do one of two things ◦ A: Protein folds▪ stays in cystol (no zipcode)▪ Goes to chloroplasts (plant cells): chloroplast targeting signal▪ goes mitochondria: mitochondria targeting signal▪ Goes to peroxisone: peroxisone targeting signal▪ Goes to nucleus: NUCLEAR LOCALIZATION SIGNAL (NLS)• Cellular zip codes are necessary and sufficient forgetting proteins to get to correct place (ex: NLS important to get to nucleus- in and out through pores)• Mutant or missing? Stays in cystol• can engineer cystolic protein to have NLSEndomembrane System• regulates protein traffic and performs some metabolic functions in the cell◦ Smooth endoplasmic reticulum, Rough endoplasmic reticulum◦ nuclear envelope ◦ transport vesicle◦ golgi apparatus ◦ lysosome • Endoplasmic Reticulum ◦ Rough: has ribosomes, protein production, involved in protein and lipid synthesis◦ Smooth: no ribosomes, lipid production (testosterone) • protein transport though the endomembrane systems lumen (inside
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