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84 Cards in this Set
- Front
- Back
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What is the purpose of feratin
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It is a protein that binds iron in a cell and stores it. However, when there's low iron in the blood, we want to inhibit the action of ferratin
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Alternative Splicing
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Producing different proteins from the same gene.
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What is spectrin
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It's an actin binding protein that links F-actin together. it also interacts with amyrin and protein 4.1 to help red blood cells keep their shape. The deficiency in spectrin leads to "hereditary spherocytosis"
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What is coflin
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It is a protein that fragments F-actin in the cell by twisting action. Helps to maintain a more "sol" in the cell
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What is Gelsolin
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It is protein that fragments F-actin by fragmenting cross-linked F chains. Needs Calcium to do this
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What is dystrophin
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It is an actin-binding protein that helps skeletal muscle attach to actin filaments. Gives skeletal muscle their tensile strength. A deficiency in this causes BMD and DMD
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Actin formation
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Lag, polymerization, steady state. nucleation state, ATP converted to ADP
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Mysosin
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myosin 2: helps with contraction, by binding head to F actin and tail to ATP. non muscle cells
myosin 1-4 used in cellular cargo |
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intermediate filaments
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alpha helical rod-like protein subunits. Found between nucleus envelope and plasma membrane. 2 coils join to form a "coiled coin" dimer, and these get together another paid to form a "tetramer". Eight of these tetramers join to form a rope like structure.
Formation of intermediate filaments require no energy, and formed anti-parallel Concrete of the cell. |
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What is actin in charge of
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Contraction, state of the cytosol, formation of contractile rings during cytokensis
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Microtubual function
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chromosomal movement, formation of cilia and flagella, and intracellular transport
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Microtubual formation
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Alpha and beta monomer get together with GTP and 13 of these get together to form a protofilament, which is embedded into mcentrosome to form nucleation site and the microtubules are built from there. beta end has the GTP cap, alpha faces the centrosome. They constantly grow and fall apart, once it's attached they're stable.
During mitosis attaches to kinetochore |
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Flagella
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9 specialized pairs of microtubules fprms a ring, and the ring surrounds 2 central mucrotuble. The structures bend and slide against each other via ATP. Dynein and kinesin are motor proteins that help to use ATP as mechanical movement. Dynein moves microtuble towards centrosome, and kinesin moves microtubule away from centrosome
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Nucleoplasm
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Fluid inside the nucleus
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Nuclear envelope
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The envelope is continuous with ER membrane and the nuclear space is continuous with ER lumen.
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Lysosome
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acidic internal pH maintained by proton pump. Enzyme acid hydrolyases works by splitting biomolecules in half. Made in Golgi
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Peroxisome
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Contains hydrolytic enzymes and they are made in the ER. Enzymes in peroxisome are synthesized on free ribosomes. Breaks down fatty acids and purines, peroxides are broken down by "catalase".
It also synthesizes myelin. Mutation in ABCD1 gene leads to accumulation of fatty acids in brain, and break down of myelin --> mental retardation |
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Three types of cells that have no connective tissue
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1) epthelial
2) muscle 3) neuronal |
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Gag
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Type of ECM. Two sugars, one is N-acetylated amino sugar, and the other is acidic sugar
Covalently attached to protein and they form proteoglycan monomers. Monomers consist of core protein with GAG extending out of it. Trunk = hyaluronic acid, brand = core protein, GAG chains = pine needles |
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Disapersen
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It's a drug that is currently in the late-stage development. It's supposed to help boys with DMD with mutation in dytrophin (frame ****)
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Histone acetylation
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increases transcription. loosens chromatin structure (euchromatin). This is done by HATs(Histone acetyltransferases) and HDACs (Histone deacetylases)
HDAC also regulate a small number of genes incharge of cell growth, differentiation, and survival) |
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DNA methylation
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Shuts off that gene, not damaged or broken. Also called imprinted
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Repetitive DNA
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There are two kinds: satellite, and dispersed repetitive.
Satellite are tandom repeats and used for paternity testing, forensics, and predicting diseases. Localized to one area Dispersed can mess up good genes and can cause cancer, hemophillia, and complement deficiency |
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DNA replication
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Helicase separates the double strands
Single stranded DNA binding proteins prevent the strands from re-annealing RNA primase lays down RNA primer which DNA polymerase 3 binds to, and starts to synthesize 5' to 3' For lagging strand: RNA primase lays down an RNA primer, DNA polymerase 3 attaches and lays down new DNA. This is repeated till it's all done. DNA polymerase 1 comes in, and replaces all the RNA primers with DNA. Ligase then comes in and links the okazaki fragments. |
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Topoisomerase
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Regulates the over and underwinding of DNA
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Transcription
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TATA box and enchancer region upstream of the part of the DNA that is to be transcripted.
Transcription factors (TF2D) and TF2A and TF2B all attach to the TATA box. This complex allows RNA polymease to bind. Other transcription factors join and complete the complex. ATP is added RNA polymerase synthesizes mRNA from DNA. Transcription factors are released |
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RNA processing
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5-cap is added to protect against degradation. Poly 3' tail is added for stability. Splicesomes convert primary RNA to mRNA by cutting out the introns.
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Translation
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mRNA gets fed into rRNA and tRNA read and bring in appropriate amino acids, which are joined together by peptide bonds.
AUG is start codon. Peptidyl transderase, GTP faciliates the growing chain. |
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Mature mRNA parts
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Left to right:
5' cap, UTR (untranslated region), coding region, untranslate region, Poly A tail |
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Proteasomal Pathway
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Targeted protein is tagged with ubuquiton with the help of ATP. Proteasome then removes the ubuquiton chain and unfolds the protein, and releases the amino acids for re use. Misfiring of this can lead to alzheimer's, infectious diseases, and RA
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Breast Cancer and Estrogen
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Elevation in estrogen results in enhanced ER activity, and this results in increase in ER regulated gene expression and promotes growth.
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RNA interference
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Presence of ds RNA cause this to trigger. RISC is formed, targets and hybridizes with mRNA. And endonucleases called "dicer" cut up dsRNA.
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Transition
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Point mutation, purine to purine
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Transversion
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Purine to pyrimide
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Polymorphism
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DNA variation that is common and doesn't affect the individual. Silent mutation, introns, spacer DNA, third nucleotide
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Transpoon mutation
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alters codon, no protein is produced. Very rare and disrupts the gene
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Translocation mutatio
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section of gene is moved from original location to another location. no production of protein
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Haploinsufficiency
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just producing 50% of gene product isn't enough and results in clinical abnormalities. Things such as Echler Danlos Syndrome, marfan syndome, polydactyly
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3 types of lipids in a cell membrane
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phospholipids, cholesterol, glycolipids
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Structure of phospholipid
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head is polar, has a phosphate and alcohol group. Can have serine, ethanolamine, inositol, and choline. (ex. phosphatidylserine). all of this attached to glycerol backbone.
Tails are fatty acids, saturated or unsaturated (makes it more rigid) |
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Sphingomyelin
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Doesn't have a glycerol backbone, contains sphingosine backbone instead. Found in membrane of neuronal cells.
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Role of cholestorel in cell membrane
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Has a polar head (alcohol) and a hydrocarbon area that is more situated with the middle of the bilayer. makes the cell more rigid and stronger.
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Glycolipids
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Lipids with carbs attached to them. Gives cells unique cell characteristics. Antigens located on RBC are done this way
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G proteins
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Uses GTP, transmembrane protein. Functions in cell signaling and responses to hormones, and participates in cell signaling.
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Phospholipids that are only found on the outside/inside
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Phophatidylcholine, and spingomyelin = outside
phosphatidylserine, phisphotidlethanal, phostidyllindostil = inside |
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Peripheral membrane proteins
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attached only to the inner leaflet
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Three functions of lipid rafts
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chilesterol transport
endocytosis signal transduction |
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Different classes of gluts
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1 &3: most tissues, basal glucose uptake
2) Located in liver, kidneys, pancreas, removes excess glucose from blood 4) Located in muscle and fat. Removes excess glucose from blood 5) Located in small intestine and tests. Transports fructose Gluts 1, 2, 3, 5 are insulin independent. For GLut4, when insulin is present GLUT 4 is expressed from Golgi to the cell surface GLUTS can only transport glucose when it's towards its concentration gradient |
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Difference between translocation and nondisjunction
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Translocation: Combining two pieces of different chromosomes
Nondisjunction: Uneven separation of chromosomes For example, Turner Syndrome is a nondisjunction disorder (NOT A TRANSLOCATION) |
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What's special about GLUT 2
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It is located on the beta cells of pancrease and helps to take glucose in when there's too much, and helps to release glucose when there's too little in the blood
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Things that don't need insulin
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Brain, white blood cells, red blood cells, and liver. GLUTS are expressed all the time
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SGLT
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it's a transport protein located on the intestine that help bring glucose in by coping it with NaCL. They are located on the apical membrane (facing the intestinal lumen)
GLUT protein on the basolateral membrane (one facing the blood stream, on the other side) transports the glucose into the blood stream. |
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Three locations where glucose is present at a higher concentration on the inside of cell, than outside
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1) choroid plexus
2) proximal convoluted tubules of the kidney 3) epithelial cell brush border of the small intestine |
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What kind of molecules/drugs can easily transport through a membrane
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Uncharged molecules
lipid soluble drugs small water soluble molecules (can use the water channels) Transport protein, or active transport processes are needed to facilitate the movement of other drugs. |
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What is a peptide transporter
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Type of solute carrier. and it helps to transport penicilin, antihypertensive drugs.
Protons and peptides are cotransported by PEPT proteins |
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Organic anion transporting peptides
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OATP helps to transport organic amphiapathic drugs.
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Organic Ion transporters
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They are involved in uptake of metformin in liver, and renal excretion of drugs and toxins
Large group of drug transporter. expressed in liver, kidney, skeletal muscle and enterocytes |
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h+/organic cation transporters
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organic cations are excreted by proton/organic antiporter. located in the enterocytes, cells that line the inside of the intestines
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ABC transporters
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ATP binding proteins that export ions, drugs, xenobiotics from cells. This is how cell develop drug resistance as these things spit out the drugs that supposed to kill them.
ABCB1 transporter inhibitor works to shove the drugs back into the cell |
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Electrolytes inside vs outside of cell
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Chloride and sodium are more on the outside than inside.
potassium is more on the inside than outside |
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Lipid rafts
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These are areas in the cell membrane that are cholesterol rich. Thus the phospholipids that are located within the rafts are extended and tightly packed
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4 things that are highly lipid soluble
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oxygen, nitrogen, alcohol, carbon dioxide
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Potassium Channels
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Hydrated potassium comes in, interacts with cabonyl oxygen which removes water from the potassium.
this interaction causes conformational change that allows potassium inside |
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Sodium channels
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Lined by amino acids that are negatively charged. The strong charge pulls and dehydrates the sodium, and sodium travels down its concentration gradient
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Nernest equation
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How much energy to stop diffusion all together
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One osmole
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Number of moles of a substance that contributes to osmotic pressure
So glucose has 1 osmole, and NaCl has 2 osmole 1 mole of glucose = 180 grams, 180 gram of glucose = 1 osmole |
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Osmolality
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measurement of osmotic potential
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What is the human reference range of osmolality in plasma
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285 to 295 milli-osmoles per kilogram
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Sodium potassium pump
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Three salts out, two potassium in. It is the most important in controlling cell volume. One net positive ion is moved outside the cell. This creates a negative charge inside the cell, and a positive charge outside the cell. Since this pump creates an electrical potential, it's called "electrogenic"
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Counter transport
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Kind of like co transport, except they are moving opposite directions. Sodium comes in, and something inside goes out. switch-a-roo.
An example of this is sodium and calcium. Cells don't like to have calcium inside the cell. Sodium/hydrogen: sodium moves into the blood, and hydrogen moves out of the blood into exterior/kidney tubules |
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Smooth ER
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Contains p450 enzymes involved in production of steriod hormones and metabolism of drugs/toxins in the liver.
Involved in synthesis of lipids, storage of glycogen in liver |
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Collagen
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It is a type of fibrous protein. They provide a lot of strength. Every 3rd amino acid is glycine, and a lot of proline is found there too
Found in bone (sheer stress relief), tendon, and ECM. Collagen 1, 2, 3 are organized in fibrils (Type 1 is most important, forms skin and etc). Collagen 4 is organized in mesh Composed of amino acids organized in three alpha helical structures. Forms a triple helix structure. |
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Type 1 collagen
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Has two type 1 alpha1, chains and one type 1 alpha2 chain
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Type 2 collagen
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Has three 2 alpha1 chain
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Collagen synthesis
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1) mRNA codes the production of alpha chains
2) Individual collagen fibrils are translated on membrane bound ribosomes = pro alpha chain (professional alphachains) 3) in ER selected lysine and proline are hydroxylated using vitamin C. And then they are glycosylated. 4) In Golgi, pro alpha chains are coiled together with glycosylated proline and lysine to form procollagen (professional collagen from professional chains). 5) These procollagen are pinched off from Golgi and excreted out of the cell 4) Procollagen peptidases found in ECM cleave off the ends of procollagen resulting in tropocollagen (professional collagen finds out what it's like in the real world, and becomes "tough") 5) Tropocollagen self assemble to form collagen fibrils 6) Lysyl oxidase modifies lysine and hydrolysine into allysine residues. 7) Allysine residues form covalent cross-links resulting in formation of mature collagen. This provides tensile strength (gets married, cross linking) |
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Elastin
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Rich in amino acids glycine, alanine, proline, and lysine. And countains hyoxyproline. No glycoslayted structures found on elastin.
Gives stretchness to tissue |
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Elastin synthesis
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1) cells secrete tropoelastin into ECM (tough elastin is sent to ECM right away)
2) Fibrilin serves as a scaffolding onto which tropoelastin is deposited. 3) Tropoelastin interacts with fibrilin and some of the lysine is modified with form allysine residues. 4) Three allysine residue and side chain of lysine from same or neighboring tropoelastin is joined covalently forming desmosine cross link (multi-marriage) [four individual polypeptide chains are covalently linked together) |
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Fribronectin and Laminin
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Adhesive glycoproteins secreted by cells into the ECM.
Fibronectin is the principle adhesive protein in connective tissue Laminin is the principle adhesion proteins in epithelial tissues They contain different domains that join protoglycans and collagen to ECM and other cells. |
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Selective adhesion
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How stem cells in the developing embryo can stay attached to to each other and ECM
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Cell junctions
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Adherens junctions: couple neighbouring cells to each other
Hemidesmosomes: Link cytoskeleton with intermediate filaments of basal lamina. Attach cells to underlying dense layer, epithelium Gap: Allow signal transfer between the cells |
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Cell adhesion molecules
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Transmembrane proteins that extends from a cell's cytoplasm, through their cellular membrane to ECM (where they attach to ligands)
Ligands can be adhesion molecules on other cells, things in the ECM, or certain molecules on other cells |
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Cadherins
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They hold cells together to maintain integrity. They extend through from cell from cytoplasm. Inside the cell, they are bound to the actin cytoskeleton (catenin), and they extend out. Cadherin molecules bind to one another to form a dimer, and these dimers then bind and interact with other cadherin dimers on other cells. This means two cells are bound together through their actin cytoskleton (indirectly).
This requires calcium, and without calcium, they sopt bind. Provides long lasting adhesion |
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Leukocyte immigration to injured cell
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When cells are injured, mast cells and phagocytes try to kill some of the invading bacteria. Mast cells release histamines and phagocytes release cytokines. These cause the endothelial cells to express selectins, which cause the white blood cells to slow down. When the cells slow down, they express integrins which allow them to have a higher affinity to the cells, and the vascodilation from the histamins allow the white blood cells to infiltrate the area and eat up bacteria
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Immunoglobulin superfamily
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Cell to cell adhesion. They fine-tune and regulate cell to cell adhesions. Facilitate adhesion of luekocytes to endothelium during injury.
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