Cellular compartments 1. Cellular compartments and their function 2. Evolution of cellular compartments 3. How to make a 3D model of cellular compartment 4. Cell organelles in the fluorescent microscope
A typical animal cells are very busy Make mrna Breakdown proteins Oxidate toxic molecules Breakdown glucose Make proteins Duplicate DNA Make ATP Add sugar to proteins Burn fat
Inside a cell, many different chemical processes are performed simultaneously Protein synthesis Protein modification Protein degradation Lipid synthesis Lipid glycosylation Oxidation of molecules ATP synthesis by oxidative phospholylation etc How do cells prevent chemical anarchy?
Chemical processes are segregated inside the cell Bacteria: Eukaryotes: Enzyme complexes Compartmentalization Compartmentalization Separation of cellular spaces by cell membranes Cell membrane a a b b a c One compartment: (a) two compartments: (a) and (b) three compartments: (a), (b) and (c)
Compartmentalization allows a cell to. b a c separate processes that might interfere independently regulate the microenvironment (ph, salt ) control dangerous molecules concentrate enzymes involved in the same process
Write down 7 membrane-enclosed compartments!
Membrane-enclosed compartments of a typical animal cell 1. Nucleus 2. Endoplasmatic reticulum (ER) 3. Golgi apparatus 4. Endosome 5. Lysosome 6. Peroxisome 7. Mitochondrion 8. Cytosol 9. [Chloroplast (plant cell)] endosome peroxisome cytosol lysosome Golgi apparatus Mitochondrion Endoplasmatic reticulum (ER) nucleus
In which cellular compartment do these processes take place? 1. DNA synthesis 2. RNA synthesis 3. Protein synthesis 4. Lipid synthesis 5. Protein modification 6. Glycolysis 7. ATP-synthesis by oxidative phosphorylation 8. Oxidation of toxic molecules 9. Degradation of wornout cell organelles and macromolecules endosome peroxisome cytosol lysosome Golgi apparatus Mitochondrion Endoplasmatic reticulum (ER) nucleus
In which cellular compartment do these processes take place? 1. DNA synthesis 2. RNA synthesis 3. Protein synthesis 4. Lipid synthesis 5. Protein modification 6. Glycolysis 7. ATP synthesis by oxidative phosphorylation 8. Oxidation of toxic molecules 9. Degradation of worn-out cell organelles and macromolecules endosome peroxisome 8 5 5 1,2 6 9 3 7 3 4 cytosol lysosome Golgi apparatus Mitochondrion Endoplasmatic reticulum (ER) Nucleus
Nucleus contains main genome DNA and RNA synthesis is surrounded by a double membrane (inner and outer membrane-> nuclear envelope) Nuclear envelope is penetrated by nuclear pores outer nuclear membrane is continuous with the membrane of the ER
ER (endoplasmatic reticulum) a dynamic system of connected sacs and tubes of membranes synthesis of new membrane (lipid synthesis) rough ER: ribosomes attached to cytosolic surface ribosomes of rough ER synthesize proteins that are delivered into ER lumen or into ER membrane Smooth ER: storage of Ca 2+
Golgi apparatus stack of membrane sacs modification and packaging of proteins and lipids situated near the nucleus receives proteins and lipids from the ER at cisface dispatches proteins and lipids to cellular destination at trans- face Trans Golgi network (TGN) Lower ph then rest of Golgi
Endosomes series of vesicles and tubes sorting endocytosed material Lysosomes small sac of digestive enzymes low ph (ph 5), ( acidic hydrolases) site of intracellular degradation of old organelles, macromolecules and endocytosed material
Peroxisomes contains enzymes that perform oxidative reactions uses molecular oxygen (O 2 ) to oxidize organic molecules makes and destroys highly reactive H 2 O 2
Cytosol contains many metabolic pathways (eg. Gycolysis) synthesis of proteins contains cytoskeleton (actin filaments, microtubuli, intermediate filament)
Mitochondrium the cells power plant: synthesis of ATP by oxidative phosphorylation surrounded by a double membrane has its own genome, makes some of its proteins (but not all)
The main function of the membrane-enclosed compartments of a eukaryotic cell Cytosol :Metabolic pathways, protein synthesis Nucleus : contains main genome, DNA and RNA synthesis endosome cytosol ER: lipid synthesis, synthesis of proteins destined for some cell organelles and plasma membrane, Ca2+ storage Golgi: modification, sorting, packaging of proteins and lipids destined for many cell organelles and plasma membrane Mitochondria: ATP synthesis by oxidative phosphorylation peroxisome lysosome Golgi apparatus Mitochondrion Endoplasmatic reticulum (ER) Nucleus Lysosomes: intracellular degradation Endosomes: sorting of endocytosed material Peroxisomes: oxidation of toxic molecules
What happens to the membrane enclosed compartments during mitosis? Nucleus Golgi ER Endosomes Lysosomes Mitochondria Chloroplasts Peroxisomes Disassembly of nuclear envelope Fragmentation into small vesicles Fragmentation? Distribution into daughter cells
Cellular compartments 1. Cellular compartments and their function 2. Evolution of cellular compartments 3. How to make a 3D model of cellular compartment 4. Cell organelles in the fluorescent microscope
How did membrane enclosed compartments evolve??
Where do mitochondria come from??
How nuclear membranes and ER might have evolved?
How cell organelles might have evolved
The making of a 3D model of cellular compartments Take a slice of a cell (insulin secreting cell from the pancreas) Look at the slice at different angles in the Electron Microscope Reconstruct a three dimensional digital image Step through the image and outline the membranes Use a computer program to build a 3D model of the outlines Cis-Golgi,Trans- Golgi Secretory Vesicles Transport Vesicles Microtubuli, Mitochondria ER, Ribosomes Endosomes
Summary 1. Advantages of membrane-enclosed compartments: Segregation of processes within the cell Independent microenvironments Control of toxic/ destructive molecules 2. Membrane-enclosed compartments of the cell: Cytosol, nucleus, ER, Golgi, lysosomes, endosomes, peroxisomes, mitochondria, chloroplasts 3. The nuclear envelope and the ER might have evolved by invaginations of the plasma membrane 4. Mitochondria and chloroplasts may have been endosymbiotic prokaryotes 5. During mitosis, membrane-enclosed compartments are divided into both daughter cells
Cellular structures can be visualized with fluorescent dyes Red Green blue
Indian muntjac deerskin cell Mitochondria
HeLa cell (human cancer cell) Mitochondria plasma membrane nucleus
gray fox lung cell Golgi apparatus
NIH 3T3 cells (mouse embryonic fibroblast) Golgi mitochondria nucleus
Viable Madin-Darby canine kidney (MDCK) cells Golgi lysosomes nucleus
U2OS (human osteosarcoma cell line ) ER
Live bovine pulmonary artery endothelial cells ER
Mitochondria ER live bovine pulmonary artery endothelial cells
Bovine pulmonary artery endothelial cell Mitochondria peroxisomes nucleus
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Reorganization of the Golgi complex during mitosis
The inner life of the cell- Animation http://multimedia.mcb.harvard.edu/media.html