Chapter 7 Draw a cell membrane according to the fluid mosaic model Indicate relative positions and orientations of phospholipids cholesterol integral membrane proteins and peripheral proteins and know their function Explain the effect of the following molecules on membrane fluidity 1 2 3 a a phospholipids with saturated fatty acids saturated hydrocarbon tails creates viscosity phospholipids with unsaturated fatty acids unsaturated hydrocarbon tails gives fluidity cholesterol a high temperatures restrains phospholipid movements and holds them together b low temperatures doesn t allow packing of phospholipids Describe the characteristics of molecules that can easily pass through the phospholipid portion of a cell membrane and those that cannot easily pass through the cell membrane proteins polysaccharides nucleic acids DNA RNA high permeability gasses very small uncharged polar molecules moderate permeability water urea low permeability polar organic molecules glucose very low permeability ions charged polar molecules and macromolecules amino acids ATP Define and understand the following terms 1 semipermeable membrane a a 2 diffusion 3 osmosis will allow certain molecules or ions to pass through it by diffusion and occasionally specialized facilitated diffusion molecules diffuse down their concentration gradient to reach a uniform distribution at equilibrium a diffusion of water across a membrane passive transport down the concentration gradient across a selectively permeable membrane Describe what happens to an animal cell and plant cell when it is placed into hypotonic isotonic and hypertonic solutions Explain why the cell reacts the way it does in each of these conditions o hypotonic solution lysed animals turgid plants solute concentration lower outside of the cell than inside water flows in explodes animal cells cell wall keeps it inside plants o hypertonic shriveled animals plasmolyzed plants the solute concentration higher outside of the cell than inside water leaves animals and plants o isotonic normal animals flaccid plants solute concentration equal on both sides Compare and contrast simple diffusion across a cell membrane with facilitated diffusion simple diffusion passive transport tendency for molecules to spread out evenly into the available space o down concentration gradient o usually small hydrophobic CO2 02 hydrocarbons facilitated diffusion passive transport transport proteins speed the passive movement of molecules across the plasma membrane Compare and contrast passive transport and active transport Passive transport does not require ATP to happen active transport requires ATP Explain how co transport works to transport molecules against their concentration gradient active transport that uses the energy from a favorable gradient to drive transport against an unfavorable gradient Describe how phagocytosis pinocytosis and receptor mediated endocytosis allows cells to take up specific molecules Phagocytosis takeup solids Pinocytosis takeup liquids Receptor mediated endocytosis Describe the process of how proteins made in the RER are transported to the cell membrane The ribosomes on the rough endoplasmic reticulum manufacture proteins which enter the channels of the endoplasmic reticulum and move to places where they can create pockets These pockets can then break off as vesicles to transport their protein cargo to the Golgi complex for distribution Chapter 8 State and understand the First and Second Law of Thermodynamics in simple terms o 1st Law Energy can be transformed or transferred but is never created or destroyed conservation of energy o 2nd Law In every energy transfer some energy becomes unusable heat which increases entropy or disorder of the universe Define and understand the terms spontaneous entropy and free energy as they are used in thermodynamics Spontaneous doesn t require energy INCREASES entropy Entropy disorder Free energy is the portion of a system s energy that is able to perform work when temperature and pressure is uniform throughout the system as in a living cell Use the G of a reaction to predict whether it would be spontaneous non spontaneous or at equilibrium Negative G spontaneous Positive G non spontaneous 0 G equilibrium no work no cells do this Explain why the ATP carries such high potential energy and why is this molecule so important o Hydrolysis of last phosphate on ATP by addn of H2O o G 7 3 kcal mole o The chemical potential energy temporarily stored in ATP drives most cellular work The energy to phosphorylate ADP comes from catabolic reactions in the cell Explain how a cell can perform anabolic reactions with strongly positive Gs Catalyst agent that speeds up the rate of a chemical reaction without being consumed during the reaction Enzymes Define the term activation energy barrier and explain how this affects chemical reactions o The initial energy needed to start a chemical rxn is called Activation energy EA o EA often supplied in the form of heat from the surroundings Explain what an enzyme is and how it affects chemical reactions Protein catalyst By lowering the EA barrier They do not affect the rxn s G or equilibrium Know the terms active site and allosteric site and their importance o Substrate binds Enzymes at very specific sites where the 3D shape of the substrate fits the 3D shape of the enzyme This is where the reaction occurs and it is called the active site Explain the factors that affect enzyme activity or rate of chemical factors General environmental factors such as Temperature and pH Chemicals that specifically influence the enzyme Compare and contrast competitive inhibition and non competitive inhibition of enzymatic activities Competitive inhibitiors bind to the active site non competitive inhibitors bind to an allosteric site and alter the shape of the active site in order to prevent substrates from binding Explain how enzyme is regulated allosterically Allosteric regulation may inhibit or stimulate enzyme activity Cooperativity amplifies enzyme activity o In cooperativity binding by a substrate to one active site affects catalysis in a different active site Feedback Inhibition the end product shuts down the pathway Explain how feedback inhibition is used to regulate biochemical pathways and how this inhibition benefits the cell As multiple products are made when there are too many a product will return and fit into an allosteric site to inhibit the production of more products Define oxidation and
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