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85 Cards in this Set
- Front
- Back
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phospholipid bilayer
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frame work of the membrane 2 layers amphipathic molecule
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fluid-mosaic model
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semifluid phospholipid bilayer with a mosiac of proteins carbohydrates may be attached to the lipids or proteins
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integral membrane protein
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aka intrinsic membrane cannot be released frm the membrane unless the membrane is dissolved with an organic solvent or detergent
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transmembrane protein
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one or more regions that are physically inserted into the hydrophobic region of the phospholipid bilayer
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transmembrane segments
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streches of nonpolar amino acids that span or transverse the membrane from one leaflet to the other.
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lipid anchored protein
(integral membrane protein) |
lipid molecule that is covalently attached to an amino acid side chain within the protein
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peripheral membrane proteins
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aka extrinsic proteins membrane protein dont interact with hydrophobic interior noncovalently bound to the regions of the integral membrane proteins that project out from the membrane or bound to polar head groups of phospholipids
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lipid raft
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a group of lipids that float together as a unit within a larger sea of lipids
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unsaturated
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when a double bond is present a lipid is unsaturated with respect to # of hydrogens that can be bound to carbon atoms
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glycosylatin
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process of covalently attaching a carbohydrate to a lipid or protein
functions: recognition signals for other cellular processes, |
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glycolipid
glycoprotein |
when a carbohydrate is attached to a lipid
" " carbohydrate is attached to a protein |
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cell coat/glycocalyx
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carbohydrate rich zone on the surface of certain animal cells that protects the cell
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lipid exchange proteins
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extract a lipid from one membrane diffuse through a cell and insert the lipid into another membrane
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membrane transport
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the movement of ions and molecules across biological membranes
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diffusion
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substance moves from a region of high concentration to a region of lower concentration
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facilitated diffusion
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transport protein provides a passageway for the substance to cross a membrane ex)diffusion
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passive transport
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transport from high concentration to low doesnt require energy
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active transport
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transport from low concentration to high or against a concentration gradient with the aid of transport protein requires energy
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transmembrane gradient
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concentration of a solute is higher on one side of a membrane than the other.
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electrochemical gradient
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dual gradient has both chemical and electrical componets solutes that have a net positive or negative charge
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isotonic
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solute concentrations on both sides of the plasma membrane are equal
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hypertonic
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solute concentration outside the cell is higher
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hypotonic
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solute concentration outside the cell is lower
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osmosis
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water diffusion across a membrane from the hypotonic compartment into the hypertonic compartment
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osmotic lysis
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cell takes up too much water and ruptures
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crenation
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shrinkage of cell if animal cells are placed in hypertonic medium
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plasmolysis
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shrinkage of cytoplasm occurs when water leaves cell by osmosis resulting in plasma membrane doesnt push against cell wall
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osmotic pressure
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hydrostatic pressure required to stop the net flow of water across a membrane due to osmosis
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turgor pressure
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plant cells osmotic pressure pushes the plasma membrane against the rigid cell wall
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transport proteins
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transmembrane proteins provide a passage way for the movement of ions and hydrophillic molecules across membranes
2 classes: channels,transporters |
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channel
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form an opened passage way for the facilitated diffusion
gated channels open to allow diffusion of solutes close to prohibit diffusion |
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transporters/carriers
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slower than channels bind their solutes in hydrophillic pocket undergo a conformational change that switches the exposure of the pocket from one side of the membrane to the other
passageway for organic molecules |
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uniporters
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bind a single ion or molecule and transport
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symporters/cotransporters
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bind 2 or more ions or molecules and transport them in the same direction
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antiporters
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bind 2 or more ions or molecules and transport them in opposite directions
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primary active transport
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involves pump directly uses energy to transport a solute against a gradient
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secondary active transport
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uses pre existing gradient to drive the active transport of another solute
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Na+/K+ -ATPase
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E1:3 Na+ bind to Na+/K+ -ATPase from the cytosol ATP hydrolyzed to ADP and phosphate phosphate temporarily bonds to pump
E2:3 Na+ relaesed 2 k+ bind from outside causes release of P the switches back to E1 |
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exocytosis
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material inside the cell is packaged into vesicles and then excerted into the extracelluar enviroment
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endocytosis
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plasma membrane folds inward forms a vesicle that brings substances into the cell
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pinocytosis
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formation of membrane vesicles from the plasma membrane as a way for cells to internalize the extracellular fluid
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phagocytosis
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extreme form of endocytosis
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kinetic E
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associated with movement
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potential E
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substance pocesses due to its structure or location
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2nd law of thermodynamics
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transfer of E from one form to another increases entropy
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entropy
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measure of randomness of molecules in a system
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enthalpy
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total E (H)
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free E
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usuable E amt of available E that can be used to do work (G)
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exergonic
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G<0 products have less E than reactants free E is released spontaneous
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endergonic
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G>0 requires addition of free E not spontaneous
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phosphorylation
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attachment of phosphate to a molecule
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coupled reaction
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net free E change for both processes must be negative in order for the endergonic rxn to occur
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active site
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location in an enzyme where the chemical reaction takes place
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substrate
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reactant molecules that bind to an enzyme at the active site and participate in the chemical rxn
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enzyme substrate complex
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binding between an enzyme and substrate
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competitive inhibitor
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molecules that bind to the active site of an enzyme and inhibit the ability of the substrate to bind
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noncompetitive inhibitor
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lowers vmax doesnt effect Km binds noncovalently to an enzymes allosteric site
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prosthetic groups
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small molecules that are permanently attached to the surface of an enzyme aid in catalysis
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cofactors
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inorganic ions temporarily bind to surface of an enzyme and promote a chemical rxn
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coenzymes
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organic molecules temporarily bind to enzyme and participate in rxn but left unchanged after rxn done
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catabolic rxn
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breakdown of molecules into smaller molecules mostly exergonic
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anabolic rxn
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synthesis of larger molecules from smaller precursor molecules mostly endergonic
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substrate level phosphorylation
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enzyme directly transfers a phosphate from an organic molecule to ADP making ATP
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CHEMIOSMOSIS
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E stored in an ion electrochemical gradient is used to make ATP from ADP and Pi
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biosynthetic rxn
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aka anaboilc rxn necessary to make larger molecules and macromolecules
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feedback inhibition
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product of a metabolic pathway inhibits an enzyme that acts early in the pathway preventing over accumulation of the product
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exonuclease
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enzyme cleaves off nucleotides one at a time from the end of RNA
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exosome
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multiprotein complex 6 membered protein ring
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proteases
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enzymes that cleave the bonds between adjacent amino acids
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proteasome
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primary pathway for protein degradation four ring stacks composed of 7 protein subunits
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ubiquitin
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directs unwanted proteins
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autophagy
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cellular material becomes enclosed in a double membrane and is degraded
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autophagosome
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double membrane structure enclosing cellular material destined to be degraded
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cellular respiration
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process living cells use to obtain E from organic molecules aim make ATP NADH
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4 metabolic pathways
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1.glycolysis
2.breakdown of pyruvate to an acetyl group 3.citric acid cyle 4.oxidative phosphorylation |
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glycolysis
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10 steps in 3 phases breakdown of sugars
1st stage yields 2 ATP 2NADH |
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E investment
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steps 1-3
2 ATP are required to begin hydrolyzed to create fructose |
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Cleavage
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steps 4-5
6carbon broken down to 3 carbon molecules of glyceraldenyde splits molecules into G3P |
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E liberation
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removes phospahte
2 glyceraldenydes broken down into 2 pyruvate molecules |
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breakdown of pyruvate to an acetyl group
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occurs in mitochondria
1NADH is made for each pyruvate and CO2 makes acetyl CoA |
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citric acid cyle
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2CO2 1 ATP 3NADH 1 FADH
acetyl removed from acetyl CoA attached to oxaloacetate to form citric acid oxaloacetate is regenerated process starts again |
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Oxidative Phosphorylation
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high E electrons removed from NADH FADH to make ATP usually requires oxygen
oxidative process involves e-chain phosphorylation occurs by ATP synthase |
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ETC
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electron transport chain
group of protein complexes and small organic molecules embedded in the inner mitochondria membrane |
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ATP synthase
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enzyme that utilizes the E stored in H+ electrochemical gradient for the synthesis of ATP via chemiosmosis
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anaerobic metabolism
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2 strategies
1.use substance other than O2 as a final e- acceptor in e- transport chain 2. produce ATP only via substrate level phosphorylation |
