55 Cards in this Set
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Fluid mosaic model
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Proposed by Singer and Nicolson, describes the structure of the plasma membrane as a mosaic of components including phospholipids, cholesterol, proteins, glycoproteins, and glycolipids
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Phospholipids
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Create a hydrophobic barrier between the cell and exterior
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Phospholipid structure
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Hydrophilic head and two fatty acid tails, 1 saturated 1 unsaturated. Makes the tail hydrophobic
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Desaturation and temperature
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Fatty acid desaturation(C=C bond) yields lower freezing point
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Protein functions
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Cell recognition, signal reception and transport
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Plasma membrane components
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Phospholipid-main component
Cholesterol-attached between phospholipids and between the two phospholipid bilayers
Integral proteins-embedded within the bilayers
Peripheral proteins-on the inner and outer surface of the bilayer
Carbohydrates-attached to proteins I the outside membrane l…
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Amphiphilic
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Molecule possessing a polar(charged) and nonpolar(uncharged) area capable of interacting with both hydrophilic and hydrophobic environments
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Passive transport
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Moves materials along their concentration gradient, no energy expended
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Facilitated diffusion
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Moved substances down their concentration gradients by using proteins as channels
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Carrier proteins
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Move molecules across cell membranes by changing shape
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Osmosis
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Passive move rn of water across cell membranes along its concentration gradient
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Tonicity
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Measurement of the concentration of the extracellular fluid that affects movement of water across the membrane (hypotonic, isotonic, hypertonic)
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Hypertonic
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Water moves out through membrane, leaving structure shriveled
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Isotonic
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Water flows evenly in and out of the structure
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Hypotonic
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Water moves into the structure through the membrane, filling it up
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What way does water always move?
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Higher concentration to lower concentration across a membrane
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What does lower concentration imply?
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More material is dissolved in the water
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Active transport
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Method of transporting material that requires energy
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Electrochemical gradient
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Gradient produced by the combined forces of an electrical gradient and a chemical gradient
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What is the overall charge of a cells interior
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Negative (3 Na+ ions out, 2 K+ ions in) cells accumulate potassium and transport sodium out
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Because of the negative charge..
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There is a greater pull for positive ions
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Primary active transport
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Uses energy (often ATP) to push material against its concentration gradient, maintaining concentration difference across membranes.
Ex. 3 Na+ ions out for each 2 K+ ions in, maintains cells negative interior charge
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Uniporter
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Carries one specific ion or molecule
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Symporter
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Carries two different ions in the same direction
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Antiporter
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Carries two different ions but in different directions
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Secondary active transport (co-transport)
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Uses a gradient generated by primary active transport to enhance the movement of a second substance across the membrane
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Endocytosis
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Movement of material into the cell by changes in the cell membrane
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Bulk transport
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Movement of macromolecules in or out of a cell. Two types-exocytosis and Endocytosis
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Phagocytosis
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Large particles such as cells or relatively large particles are taken in by a cell
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Pinocytosis
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Imports molecules that the cell needs from the extracellular fluid
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Receptor-mediated Endocytosis
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Involves the use of specific binding proteins in the plasma membrane for specific molecules or particles
Involves an invagination of the cell membrane
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Clathrin
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Stabilizes the membrane
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Familial hypercholesterol
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Folks lack the LDL receptor, cholesterol can't be removed from the blood
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Exocytosis
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Release of material from a cell by changing the cell membrane
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Producers
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Convert sunlight into biomass
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Consumers
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get their energy by consuming the producers
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Photosynthesis
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Light energy generates ATP and NADPH to convert CO2 to biomass
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ATP
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Chemical energy
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NADPH
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Electron source for biosynthesis
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Oxidation
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Removal of electrons from a compound
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Photosynthesis equation
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6CO2 + 6H2O + light energy --> C6H12O6 + 6O2
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Calvin cycle equation
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C6H12O6 + 6O2 --> 6CO2 + 6H2O + energy (ATP and NADPH)
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Breaking chemical bonds (catabolism)..
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Of glucose releases energy
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How much ATP is needed per glucose oxidized
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36-38
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Complete oxidation of glucose..
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Yields CO2
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Metabolic pathway
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Series of linked reactions that take a substrate and convert it into a product
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Anabolic pathway
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Converting a substrate into a more complex structure (requires energy)
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Catabolic pathway
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Converts substrate into less complex structure (tends to release energy)
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Potential energy
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Stored energy
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Kinetic energy
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Energy of movement or activity
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Enthropy
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Level of disorder or randomness in a system
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Activation energy
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Amount of energy required to start the reaction
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First law of thermodynamics
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Amount of energy in the universe cannot change, energy cannot be created or destroyed
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Second law of thermodynamics
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Energy transfers are inefficient therefore, in every energy transfer some energy is "lost" (released in an unusable form-generally heat)
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Enzyme
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Protein catalysts-facilitate reactions without being destroyed in the process.
Reduce amount of activation energy required to begin a reaction
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BIOL 2050: Exam 3