1Cell Membrane, Transport, Enzymes, & Energy Unit 4 Review
2The Cell Membrane helps maintain Homeostasis by regulating transport of materials in/out of the cell.
3Function of the Cell Membrane The Cell Membrane is like theof the cell because it controls what can come in and out of the cell.Security Guard
4PLASMA/CELL MEMBRANEThe Cell Membrane is the barrier between the cytoplasm and the ExtraCellular Fluid (outside) of the Animal Cell.In Plant Cells (and other types), it separates the cytoplasm from the Cell Wall.
5Cell Membrane Structure Phospholipids make up the majority of both layers of the cell membrane.Carbohydrate chains (glycolipids & glycoproteins) are always on the OUTSIDE of the membrane.Cholesterol adds structure and stability to the cell membrane. It makes up about 20% of the cell membrane.
6Phospholipids Hydrophilic phosphate heads = love water Hydrophobic fatty acid tails = repel water
8This process is called Diffusion. SoluteThe sugar molecules are spreading out. Solvent
9Molecules always move from HIGH concentration to LOW concentration Molecules always move from HIGH concentration to LOW concentration. It takes added ENERGY to move from low concentration to high concentration.Semipermeable means that it is selective about what can enter or leave, kind of like a picky eater.
10Molecules that easily diffuse across the membrane are Hydrophobic (O2/CO2) or SMALL & Uncharged/Polar (H2O).Sugars can NOT diffuse because of SIZE (too big). Ions can NOT diffuse because of CHARGE (charged & large molecules can not get across).
11This is called moving WITH the concentration gradient (HIGH to LOW). Does the cell have to use energy for this? NOThis is called PASSIVE Transport.
12The diffusion of WATER is called OSMOSIS. This means that H2O is moving from where there is MORE H2O & LESS solutes TO where there is LESS H2O & MORE solutes.Does the cell have to use energy for this? NOThis is called PASSIVE Transport.
13Hypotonic Solution = Cell swells because H2O diffuses (osmosis) INTO the cell. Animal cells may burst. Plant cells have increased turgor pressure but are protected by their cell walls.
14Isotonic solution = SAME concentration as the cytoplasm of the cell Isotonic solution = SAME concentration as the cytoplasm of the cell. H2O diffuses (osmosis) IN & OUT of the cell at the same rate. The cell stays the same size.
15Hypertonic Solution = Cell shrinks because H2O diffuses (osmosis) OUT of the cell.
16Facilitated Diffusion HIGH ConcentrationLarge or polar molecules MUST diffuse through a Channel ProteinLOW Concentration
20Active Transport to LOW Concentration MUST USE ENERGY HIGH Concentration
21ACTIVE TRANSPORT This is moving AGAINST the concentration gradient (LOW to HIGH)Does the cell have to use energy for this? NOThat is why it is called ACTIVE Transport!(ATP is the energy molecule) ENERGY
22This is called the SODIUM (Na+)/POTASSIUM (K+) Pump Active Transport!The Na+/K+ Pump moves 3 Na+ ions out of the cell & 2 K+ ions into the cell for every molecule of ATP. This ION PUMP controls Neuron function.
23Other Transport Mechanisms Into the cellOut of the cellImportExport
24Types of Endocytosis Phagocytosis = takes in food/large particles Pinocytosis = takes in fluidReceptor Mediated = will only take in specific molecules
29so they are very specific ENZYMESENZYMES are PROTEINS that are used in many chemicals reactions. They are necessary for living things because they SPEED UP (accelerate) important chemical reactions by lowering the amount of ACTIVATION ENERGY needed to start the reaction.Enzymes & Substrates have to fit together (complementary shapes) at the ACTIVE SITEso they are very specificEnzymes are reusable because they are not permanently changed in the reaction.Enzymes help weaken or form chemical bonds so that the reaction takes less energy to occur.
30Higher Cost (more energy required) LOWER Cost (less energy required)Activation energy is like the COST of the reaction & the enzyme is like a COUPON because it lowers the cost.
31Enzyme-Substrate Complex Reactants = SUBSTRATESSubstrates bind to the enzyme at the ACTIVE SITE to provide a place for the reaction.The Enzyme is NOT permanently CHANGED in the reaction = Reusable
32The Cell’s Energy Molecule = ATP ATP = Adenosine Triphosphate2 Phosphate groups3rd Phosphate groupAdenineRibosetriphosphateChemical bonds store ENERGYAdenosine
33ATP - P = ADP RELEASES energy This is called HYDROlysis
34ADP ATP This is called PHOSPHOrylation ADP + P = ATP STORES energy Glucose gets broken down during Cellular Respiration so that energy can be stored in ATP.
35The products go through the occurs in theoccurs in theoccurs in theThe products go through theIs broken down duringproducesproducesTOTAL 36producesCellular Respiration EquationC6H12O O2 6CO H2O + 36ATP32
36Take the Multiple Choice Quiz & Check Your Answers!