Popular in Cell Biology
Popular in Biology
verified elite notetaker
This 3 page Class Notes was uploaded by Kali Webster on Monday February 29, 2016. The Class Notes belongs to 327 at Texas Christian University taught by in Spring 2016. Since its upload, it has received 13 views. For similar materials see Cell Biology in Biology at Texas Christian University.
Reviews for Cell Biology
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 02/29/16
Week 3 - Chapter 15 - KNOW ORGANELLS AND FUNCTION - 54% cytosol, 22% mitochondria, 12% ER, 6% nucleus, 3% Golgi apparatus - All organelles are surrounded by a lipid bilayer like the plasma membrane - The address in the protein is always an amino acid which tells the protein where to go o Proteins enter the nucleus through nuclear pores o Nucleus is very rigid/stiff cytoskeleton o Go through a meshwork of filaments to get into the nucleus o NLS sequence- “take me to the nucleus” o Nuclear importer will bind to the protein with the NLS, and it will dumb its cargo into the nucleus o Ran-GTP (when importer and nuclear protein comes into the nucleus) causes the importer to dump its cargo When importer makes it to the cytosol, the Ran-GTP is hydrolyzed, Ran-GDP is then fallen off o NF-AT (T-cells) normally in the cytosol, phosphorylated, the nuclear sequence is hidden, sits in cytosol, when phosphate groups are taken off (calcineurin-phosphatase (when calcium is there)), when calcium levels are low (nucleus) calcineurin falls off and NF-AT is taken out of the nucleus - proteins unfold to enter mitochondria and chloroplasts o membrane is more fluid o transport proteins in the membrane o two lipid bilayers some proteins need to be in lumen, matrix, inner membrane, or outer membrane o cytosol to matrix TOM (transporter of outer mitochondrial membrane), TIM (inner) Multi-pass proteins When the protein arrives to the transport protein, the protein has to be stretched out in a long peptide strand (chaperone protein help the protein to not fold back (Hsp70)) ATP (NEEDED) causes the removal of Hsp70 Once protein is in the matrix, peptidase will cleave the signal sequence off the protein - Peroxisomes o Proteins enter peroxisomes from both the ER or cytosol o Peroxisomes are detoxifiers o Form myelin when myelin is wrapped around the axon, the proteins are pushed to the side Na+ cannot get out until it passes the myelin chief (Na+ jumps and causes the action potential to go faster) Phospholipid is made in the peroxisome which makes myelin Zellweger Syndrome (mutates in the Pex2 gene)’ Week 2, Lecture 2 - Cathrin has adapter protein (adaptin) recognizes cargo proteins o Phosphatidylinositol’s reacts with dynamin and sequences, you end up with vesicle dynamin falls offadaptin falls off vesicle Dynamin requires energy in the form of Mutation in dynamin loses functioning in peripheral nerve neurotransmitter release (Charcot-Marie-Tooth) destroys neurotransmitters to make muscles contract - Vesicles has to dock in order to embed proteins in the plasma membrane o RAB vesicle docking Interact with vesicle by phosphatidylinositol’s Tethering protein recognizes RAB and brings it close to the target membrane Requires Ca2+ to come in the SNARE proteins (in vesicle and membrane) SNAREs interact In the presence of Ca2+, they twist together and pull membrane pieces of vesicles and target membrane together Inner leaflet of target membrane and outer leaflet of vesicle bind together after SNAREs start twisting then you end up with inter leaflet of vesicles forming into the outer leaflet of target membrane Synaptotagmin is the Ca2+ sensor interacts with vesicle SNARE and allows the SNAREs to interact (ESSENTIAL FOR VESICLE TO FUSE TO MEMBRANE) SNARE proteins are targets for toxins (tetanus, Botox, etc.) o RAN in the nucleus Week 2, lecture 3 - Calcium, action potential, voltage-gated channel, and sodium potassium pumps is required for neurotransmitter release - Which is not needed for vesicles fusion: RAB - Proteins embedded in the membrane usually have - Carbohydrates are added in the lumen of the ER and the lumen of the Golgi - Lipids link to proteins in the ER and the Golgi where sugars are added (glycolipids) o GPI-linked proteins (glycolphosphatidylinosital) o We almost never find GPI-linked proteins in the cytosol side of the cell membrane or the outside of the Golgi/ER membrane - Chaperone proteins (BIP/HSP70) bind to proteins to help them fold properly o Proteins that fold incorrectly mutations in the chaperone proteins o Proteins aggregate together and they clog up cells o ER and cytosol - If they fold incorrectly the cell ramps up production of new proteins - TOW protein aggregate together, microtubules fall apart, then the proteins aggregate together, and neuron doesn’t work Alzheimer’s o Cell then turns up transcription and translation of the TOW proteins ER gets bigger - Sensory mechanisms when the signals detect a change in the folding, there is a signal that goes into the cytosol (heat shock proteins are an example of this) - What happens in the Golgi modification starts at the cis part is closest to the ER and goes to the trans side - Targets: o Plasma membrane secrete o Secretory pathways Constitutive pathway just dumping things out Regulated secretion pathway is signaled - Endocytic pathways: o Phagocytosis--. Macrophage destroys bacterium (surrounds its membrane around) brings to (driven by receptor by signals in the macrophage reorganizes the cytoskeleton and pushes its own membrane around) o Pinocytosis bring in fluid and small molecules outside of the cell Primary mechanism to recycle the membrane o Receptor-driven endocytosis Cholesterol in the cell cholesterol is packaged in LDL binds to LDL receptorsrecruits clathrin in the cell membrane forms vesicle with receptor and LDL in them Recycling pathway vesicles fuse and form large endosome PH drops and LDL with receptor breaks free and then be able to signal again at the plasma membrane o What do you do with everything inside the vesicle? Recycle back out (LDL receptor/aquaporin’s) Bring it to lysosome and degrade it Trans-cytosis: happens in the gut IgA has an important function in the lumen but made on the underside of the epithelial tissue of the gut IgA binds to receptor membrane buds off vesicles have receptor (IgA molecule in them) fuse on the top membrane in the gut goes out and antibody is not in the lumen o Lysosome: all acidic enzymes in the lysosome You put an ATP-driven pump on the lysosome and brings H+ inside the cell
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'