BIO 105 1st Edition Lecture 6 Energy Enzymes and Membrane Transport Lecture Outline I Know the significance of ATP II Be able to identify Endergonic reactions and Exergonic reactions III Know the difference between Passive Transport Active Transport Diffusion and Osmosis IV Know the characteristics of Light Independent Reactions and Light Dependent Reactions ATP main energy carrier in cells makes everything run in your body Can give up phosphate group to another molecule releases energy The energy in an ATP molecule rebuilds cell s DNA synthesizes and builds enzymes Endergonic reactions Anabolic Pathway Absorb energy or add in energy and yield projects rich in potential energy you have more energy Putting in energy Ex Photosynthesis Exergonic reactions Catabolic Pathways Breaking it down taking it out less energy Losing energy Yield Products that contain less potential energy than their reactants Ex Aerobic Respiration Remember EXergonic means the energy has to Exit Enzymes 5 characteristics 1 Enzymes speed up metabolic reactions by lowering energy barriers 2 Enzymes are substrate specific react with specific substances LOCK AND KEY FIT These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute 3 The active site is an enzyme s catalytic center causes reaction 4 A cell s physical and chemical environment affects enzyme activity ie Salt pH etc 5 Enzymes are reusable they are not destroyed Enzymes are proteins Activation Energy For a reaction to occur an energy barrier must be surmounted this is the energy of activation Enzymes make the energy barrier smaller Factors Influencing Enzyme Activity 1 Coenzymes and cofactors 2 Allosteric regulators 3 Temperature 4 pH 5 Salt Concentration Passive Transport Does not require energy inputs Solutes diffuse through a channel inside the protein s interior or move directly through Ex A lot of people in the elevator rush out when the doors open to leave a place from a highly concentrated area to a less concentrated area Active Transport Requires ATP Pumps solute against its concentration gradient Ex A lot of people in the elevator and another family of forces their way into the elevator Active Transport proteins act as pumps moving substances across membrane against concentration gradient usually using ATP Diffusion simple and facilitated The passive net movement of like molecules or ions down a concentration gradient Diffusion Hydrophobic molecules and very small uncharged non polar molecules diffuse directly through membrane passive Facilitated Diffusion Hydrophilic substances and larger molecules diffuse through membranes with assistance of transport proteins passive Factors Affecting Diffusion Rate Steepness of concentration gradient steeper gradient faster diffusion Molecular size smaller molecules faster diffusion Temperature higher temperature faster diffusion Electrical or pressure gradients Osmosis Osmosis passive movement of water down its concentration gradient passive Hypotonic solution Make plants Turgid plump swell healthy state plant prefer to be hypotonic solution More water outside the plant the water wants to be on the inside of the plant Other Membrane Traffic Endocytosis movement into cell o Phagocytosis cell eating bigger molecules o Pinocytosis cell drinking little droplets of fluid o Receptor Mediated Cholesterol Exocytosis movement out of cell Lecture 10 Photosynthesis Chlorophylls Photosynthetic pigments in plants green algae and some bacteria Absorb all wavelengths but green yellow green Chlorophyll a greatest Photosynthesis Light Dependent reactions cyclic and noncyclic o Occur in Chloroplast o Occur in Thylakoid membrane system o Cyclic Pathway ATP forms require photsystem o Noncyclic Pathway ATP and NADPH form water is split and oxygen released requires two photsystems Light Independent reactions Calvin Benson Cycle o Make Glucose o Occur in Chloroplast o Reactions occur in the stroma o Thylakoil membrane water gets split oxygen is released Hydrogen runs the ATP synthate pump