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29 Cards in this Set
- Front
- Back
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Compartments/organelles
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Eukayotic cells use a strategy to confine different metabolic processes and the proteins which are required for them within different membrane-enclosed...
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Animal Cell contains
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about 10 billion (10^10) proteins of molecules of ~10000 kinds, and the synthesis of them begins in the cytosol.
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Each organelle contains
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its own characteristic set of proteins
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Each newly synthesized protein
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is delivered specifically to the cell organelle
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Protein sorting
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the transfer of proteins from the cytosol to different compartments
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Vesicular transport
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the process by which different organelles communicate with one another by forming small vesicales
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Exocytosis
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The process by which vesicular transport is responsible for releasing proteins from the cell
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Endocytosis
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the process for importing proteins from the outside
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Endosome
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A membrane-enclosed compartment of a eucaryotic cell through wich endocytosed material passes on its way to lysosomes.
-sort the ingested material -recycle some back to the plasma membrane |
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Cytoskeletal filaments
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provide tracks for moving the organelles around and also direct the traffic of vesicles between them
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Peroxisomes
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small organelles which contain oxidative enzymes which break down lipids and destroy toxic molecules
-utilize oxygen |
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Oxidative enzymes
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catalase
urate oxidase |
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hydrogen peroxide
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peroxisomes are named so because they use molecular oxygen to remove hydrogen atoms from specific organic molecules in the oxidation reaction that produces...
-catalase then uses hydrogen peroxide to oxidize a variety of other organic substrates, including etoh...25% of etoh we drink is oxidized to acetaldehyde in liver cells in this way. |
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The nuclear membranes and the membranes of the ER, the Golgi app, endosomes and lysosomes are believed to have orginated
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by invagination of the plasma membrane in a very ancient prokaryotic cell.
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The interior of these organelles
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is topogically equivalent to the exterior of the cell
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Mitochondria are thought to have originated
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when a bacterium was engulfed by a larger pre-eukaryotic cell.
-explains why they contain their own genomes -and why the lumens of these organelles remain isolated formt he membrane traffic that interconnects the lumesn of many other inracellular compartments |
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Proteins are made in the cytosol and then delivered to different locations...
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1. for some organelles, including the mitochondria, peroxisomes, the interior of the nucleus, and the ER proteins are delivered directly from the cytosol.
2. For others, including the golgi app, lysosomes, endosomes and the nuclear membranes, proteins and lipids are delivered indireclty via the ER |
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3 different mechanisms by which proteins move from one compartment to another...
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1. gated transport - through nuclear pores
2. transmembrane transport (protein translocators) across membranes 3. vesicular transport by vesicles ---each mechanism requires an input of energy! |
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Vesicle budding
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from one compartment ex. the ER
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Vesicle budding
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from one compartment ex. the ER
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Vesicle fusing
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with another compartment Ex. the Golgi app
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budding and fusing
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soluble components are transferred from lumen to lumen.
-membrane is also transferred |
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target-compartment membrane
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the original orientation of both proteins and lipids in the donor-compartment membrane is preserved...
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The orientation of the bilayer relative to the cytosol is
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preserved during vesicular transport
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All cell membranes, whether the external plasma membrane or an inracellular membrane surrounding an organelle
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have distinct inside and outside faces
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the cytosolic face
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is always adjacent to the cytosol
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the noncytosolic face
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can be exposed to either the cell exterior or the interior space of the organelle
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proteins are dispatched to their specific destinations because
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each protein has a specific amino acid sequence in its structure
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the amino acid sequence contains a sorting signal
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which serves as a specific address label
-those proteins that lack remain as permanent residents in the cytosol |
