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Descrição
FlashCards por Savannah Kaminski, atualizado more than 1 year ago
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Criado por Savannah Kaminski
quase 7 anos atrás
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| Questão | Responda |
| What is the inside rule? | There is Lys His and Arg on the cytoplasmic face of membranes |
| What is a beta sheet? | There are 20+ transmembrane segments that line a cylindrical hydroPHOBIC interior of the lipid bilayer |
| Porin | Proteins that allow certain polar solutes to pass the outer membrane |
| What is the liquid-ordered state? | This occurs when temp is below physiological temp. The movement of individual lipids is highly constrained |
| liquid-disordered state | Above phys temps. Side chain fatty acids and in constant motion produced by rotation on the C-C bond and by LATERAL DIFFUSION of a single lipid in the plane of the bilayer |
| When temperatures are in the physiological range, how long chain saturated fatty acids pack? | Liquid ordered gel phase |
| When temperatures are in the physiological range, how short chain unsaturated fatty acids pack? | They cannot pack as easily so they prefer the disordered state |
| What effects do sterols have on lipid bilayer fluidity? | -For phospholips that have unsaturated fatty acyl chains sterols fill the spaces between them which prevents them from moving. -For sphingolipids and phospholips that have long saturated fatty acid chains, sterols interfere with the dense packing causing an increased fluidity |
| Flippases | catalyze translocation of an a.phospholipids, phosphatidylethanolamine and phosphatidylserine from the extracellular fluid to the cytosolic leaflet on the plasma membrane -They use one ATP per molecule of phospholipid translocated -P-type ATPases |
| Floppases | Cytosolic to the extracellular fluids ATP dependent |
| Scrambleases | Proteins that move phospholipids down its concentration gradient NOT ATP DEPENDENT |
| Caveolin | An integral membrane protein that have 2 globular domains that are connected by a hair-pin shaped hydroPHOBIC domain; which binds the protein to the CYTO leaflet |
| What do caveolin dimers associate with? | Cholesterol-rich mem regions |
| What do the caveoli dimers cause? | They force the lipid bilayer to curve, forming caveolae |
| What are some examples of things that are found in rafts and possibly caveolae | GTP-binding proteins Receptors for insulin, protein kinases and other signaling proteins |
| What are V-SNARES | SNAREs in the cytoplasmic face of the intracellular vesicle |
| What are t-SNAREs | SNAREs in the target membrane with which the vesicles fuse |
| Intergin | surface adhesion proteins that mediate a cells interaction with the extracellular matrix and w other cells. including some pathogens -They are all heterodimeric; 2 a and 2 b subunits which are anchored into the membrane by a single transmem helix |
| Cadherin | -"Ca dependent adhersion" -undergo hemophilic interactions with identical cadherins in adjacent cells |
| Selectins | Have domains that bind to specific polysacc on the surface of an adjacent cell |
| Facilitated Diffusion | down the electrochemical gradient |
| What effects how a charged solute moved across a membrane? | Chemical gradient electrical gradient |
| What is a permease? | Is a membrane protein that speed the movement of a solute across a membrane by facilitating diffusion |
| What is a transporter? | They bind their substrate with high specificity, catalyze transport at rates well below the limits of free diffusion -Show saturation kinetics |
| 4 Steps of glucose transport | 1. Glucose in blood plasma binds onto T1 2. There is a conformational change from glucose (OUT)-T1 to glucose (IN)-T2 allowing for the transmembrane passage of the glucose 3. Glucose is released from T2 into the cytoplasm 4. The transporter returns to T1 conformation |
| The higher the Kt | The lower the affinity |
| What are the 2 trademarks of passive transport shown by GLUT1? | 1. High rates of diffusion down a concentration gradient 2. Saturability 3. Specific |
| What is the Kt of the livers GLUT 2 transporter? | 17 mM, it is 5X higher than GLUT1 because the liver maintains blood glucose levels. |
| What happens in passive transport? | a chemical moves down its electrochemical gradient and is not accumulated above the equ concentration |
| What happens in Active transport? | it results in the accumulation of a solute above the equ point |
| Is active transport thermodynamically favorable or unfavorable? | UNfavorable- it needs an exergenic response such as ATP hydrolysis |
| What type of transport is directly related to a chemical reaction | Primary Some examples are: ATP to ADP and Pi oxidation reduction |
| What occurs when there is an endergonic and exogonic? | Secondary -Ender=Up hill -Exo=Down Hill |
| P-type ATPases transport what? | Cations, they are reversibly phosphoralated by ATP -This causes a conformation change that is central to moving a cation across the membrane |
| What is the membrane potential for animals ? | -50 to -70 mV |
| V-Type ATPases | They are responsible for acidifying -intracellular compartments (V for vacoule) -lysosomes -endosomes -Golgi complex -secretory vesicles |
| V-type ATPase proton pumps maintain the vacuoles at a pH of.... | 3-5 |
| In V-type ATPases the integral domain (V0).... | serves as a proton channel |
| n V-type ATPases the peripheral domain (V1).... | contains the ATP-binding site and the ATPase activity |
| F-type ATPases | are associated with ATP synthesis in bacteria and eukaryotes |
| Why is F-type called F-type | because of the coupling of electron transport with the synthesis of ATP "coupling factor" |
| What is the function of the F0 region?x | provides a transmembrane pathway for protons |
| F1 | the peripheral proteins F1 binds to ADP, Pi or ATP and is coupled to ATP synthesis in mitochondria, chloroplasts and bacteria and are called ATP synthases |
| P- and F- type are __________ | rotary engines linked to proton transport |
| What is the function of ABC transporters | Pump a.a., peps. proteins, ions, lipids, bile salts, and hydrophobic compounds (drugs) out of the cell against the concentration gradient |
| What is an ABC transporter in humans | multi drug transporter- it is responsible for resistance of some tumors to anti tumor drugs |
| MDR1 | An integral membrane protein with 2 hemo halves, each with 6 transmembrane helices and a cytoplasmic ATP-binding domain (cassette) -2 NBDs -2 transmembrane domains containing multiple transmembrane helices |
| What is the parent fatty acid for omega-6 | Linoleic Acid (LA) |
| What is the parent fatty acid for omega-3 | α-linolenic acid (ALA) |
| What are the 2 polyunsaturated fats? | linoleic acid (LA, 18:2 (∆9,12)) and α-linolenic acid (ALA, (18:3 (∆9,12,15) |
| Which has weaker interactions, saturated or unsaturated? | unsaturated fatty acids, a cis double bond forces a kink in the hydrocarbon chain. Fatty acids with one or several such kinks cannot pack together as tightly as fully saturated fatty acids, and their interactions with each other are therefore weaker. |
| What is the simplest lipids constructed from fatty acids? | Triglycerides |
| What are triglycerides composed of and what are they? | 3 fatty acid each in an ester linkage with a single glycerol molecule -nonpolar, hydrophobic molecules, essentially insoluble in water |
| What are the two significant advantages to using triacylglycerols as stored fuels, rather than polysaccharides | 1. First, the carbon atoms of fatty acids are more reduced than those of sugars, so oxidation of triacylglycerols yields more than twice as much energy per gram than carbohydrates 9 kcal/gram versus 4 kcal/gram, respectively. 2. triacylglycerols are hydrophobic and therefore unhydrated, the organism that carries fat as fuel does not have to carry the extra weight of water of hydration that is associated with stored polysaccharides |
| What is an example of a triglyceride that is only saturated fats? | Tristearin, white and greasy solid at room temp |
| Why do lipids go rancid? | oxidative cleavage of double bonds in fatty acids producing aldehydes and carboxylic acids of shorter chain length and higher volatility |
| How do they increase the shelf life of oils? | Converting the cis double bonds to single bonds ALSO partial hydrogenation has another effect: some cis double bonds are converted to trans double bonds form trans fats |
| What happens when you consume trans fats? | raise the level of triacylglycerols and of LDL ("bad") cholesterol in the blood, and lower the level of HDL ("good") cholesterol |
| What are biological waxes? | esters of long chain saturated and unsaturated fatty acids with long chain alcohols |
| Do triglycerides or waxes have a higher melting temp? | Waxes |
| How to birds keep their feathers water resistant? | They release waxes from their preen gland |
| What does amphipathic mean? | one side is hydrophobic and one is philic |
| What is an example of a storage lipid? | Triglycerides |
| What are the derivatives of phospholipids? | Glycerophospholipids Sphingolipids |
| What are Glycerophospholipids? | are membrane lipids in which two fatty acids are attached in ester linkage to the first and second carbons of glycerol, and a highly polar or charged group is attached through a phosphodiester linkage to the third carbon |
| Do Glycerophospholipids have any type of symmetry? | -Prochrial -no symmetric carbons |
| half of the heart phospholipids are ________________ | plasmalogens |
| Chloroplasts contain what kind of lipids? | -Galactolipids -Sulfolipids |
| Where are galactolipids localized? | thylakoid membranes |
| Do sphingolipids contain glycerol? | NO |
| What is a ceramide? | -When a fatty acid is attached in amide linkage to the -NH2 on C-2 -very similar to a diacylglycerol. -The structural parent of all sphingolipids |
| What are the 3 types of sphingolipids? | -Sphingomyelins -Glycosphingolipids -ceramides |
| What determines blood type? | The carbohydrate moieties of certain sphingolipids |
| What lipid corresponds to the A and B antigen for blood type? | A) N-acetylgalactosamine B) galactose group |
| A-type phospholipases remove..... | 1 of the 2 fatty acids, producing a lysophospholipid (this is occuring in the membrane) -Lysophospholipases remove the remaining fatty acid |
| What is the difference between paracrine and endocrine hormones? | Paracrine- act on cells near hormone synthesis Endocrine- are transported in the blood |
| What are the functions of Eicosanoids? | reproductive, inflammation response, formation of blood clots, regulation of blood pressure, gastric acid secretion |
| Where are All eicosanoids are derived from? | arachidonic acid |
| What are the three classes of eicosanoids | prostaglandins, thromboxanes, and leukotrienes |
| What is the function of NSAIDs? | To block the formation of prostaglandins and thromboxanes from arachidonate by inhibiting the enzyme cyclooxygenase required for their synthesis |
| What are the functions of prostaglandin | -Some stimulate contraction of the smooth muscle of the uterus during menstruation and labor -Blood flow -sleep-wake cycle -responsiveness of certain tissues to hormones such as epinephrine and glucagon -elevate body temperature (producing fever) and cause inflammation and pain |
| What are Thromboxanes? | -6 membered ring -they are produced by platlets and act in the formation of blood clots |
| Leukotrienes | first found in leukocytes, contain three conjugated double bonds. They are powerful biological signals. For example, leukotriene D4, derived from leukotriene A1, induces contraction of the smooth muscle lining the airways to the lung. • Overproduction of leukotrienes causes asthmatic attacks, and leukotriene synthesis is one target of antiasthmatic drugs such as prednisone |
| isoprenoid pathway (also called mevalonate pathway, or HMG-CoA reductase pathway) | roduces two five-carbon building blocks called isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP), used to make isoprenoids: diverse biomolecules such as cholesterol, heme, vitamin K, ubiquinone, and all steroid hormones. |
| Retinal | s the pigment that initiates the response of rod and cone cells of the retina to light, producing a neuronal signal to the brain. |
| What does β-carotene get coverted to? | Vitamin A |
| Vitamin E is the collective name for..... | tocopherols (contain a substituted aromatic ring and a long isoprenoid side chain) |
| Tocopherols | are antioxidants |
| Vitamin K | used in blood clotting |
| Vitamin K1 is found.... | in green plant leaves |
| vitamin K2 is found..... | in bacteria in the intestine |
| Warfarin | Stops formation of prothrombin -deadly to rats -is used to prevent excessive clotting in humans |
| Ubiquinone (also UQ or coenzyme Q) and plastoquinone | lipophilic electron carriers in the oxidation-reduction linked synthesis of ATP in mitochondria and chloroplasts, respectively. • Both ubiquinone and plastoquinone can accept either one or two electrons and either one or two protons. |
| dolichols | form hydrophobic interactions with membrane lipids, anchoring the attached sugars to membrane, where they participate in sugar-transfer reactions |
| Conjugated dienes | have alternating double bonds, this structural arrangement allows the delocalization of electrons, the compounds can be excited by low-energy electromagnetic radiation (visible light), giving them colors visible to humans and other animals |
| Polyketides | They are secondary metabolites that gives their producers an ecological advantage. • Many polyketides find use in medicine as antibiotics (erythromycin), antifungals (amphotericin B), or inhibitors of cholesterol synthesis (lovastatin). |
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