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Metabolism

Metabolism. I. The nature of energy A. 2 kinds of E B. First law of thermodynamics C. Second law of thermodynamics II. The nature of metabolism A. Energy changes in metabolic reactions: endergonic and exergonic B. Metabolic pathways: 2 types III. ATP: the main Energy carrier

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Metabolism

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  1. Metabolism I. The nature of energy A. 2 kinds of E B. First law of thermodynamics C. Second law of thermodynamics II. The nature of metabolism A. Energy changes in metabolic reactions: endergonic and exergonic B. Metabolic pathways: 2 types III. ATP: the main Energy carrier A. Structure and function of ATP B. The ATP/ADP cycle IV. Enzymes A. Enzyme structure and function B. Effects of temperature and pH on enzymes V. Cell Membranes

  2. I. The nature of energy A. 2 kinds of E B. First law of thermodynamics A. 2 kinds of energy B. First law Energy cannot be created or destroyed. kinetic potential Implications of First Law: 1. The energy of the Universe is a constant. 2. The energy of the Universe has existed forever.

  3. C. Second law of thermodynamics In every energy exchange, there is a loss as heat energy. Heat energy is a loss because it cannot do the work of the cell. Closed system: no energy input from outside source Open system: receives energy input from outside source Entropy: a measure of disorganization in a system Energy flow through an Ecosystem. Primary producers get the energy first and convert it into chemical energy on which the rest of the ecosystem depends. One way flow: in as light energy– out as heat energy Transfer: 90% loss – 10% capture *Kinetic energy = Heat energy + Free Energy

  4. A-B A + B A + B A-B II. The nature of metabolism A. Energy changes in metabolic reactions: endergonic and exergonicB. Metabolic pathways: 2 types Exergonic graph? exergonic E out E in endergonic Energy from exergonic rx used to drive endergonic rx. B. Metabolic pathways Catabolism: break down Anabolism: synthesis coupled rx

  5. A cow must eat at least 100 pounds of grain to gain less • than 10 pounds of muscle tissue. This illustrates • the first law of thermodynamics. • the second law of thermodynamics. • that some energy is destroyed in every energy conversion. • that energy transformations are typically 100% efficient.

  6. Glucose molecules provide energy to power the swimming • motion of sperm. In this example, the sperm are changing • a. chemical energy into potential energy. • b. kinetic energy into chemical energy. • c. chemical energy into kinetic energy. • d. kinetic energy into potential energy.

  7. The energy available to do work is a. free energy b. kinetic energy c. heat energy d. potential energy

  8. Which of the following is correct? a. kinetic energy = potential energy + heat energy b. kinetic energy = free energy + potential energy c. kinetic energy = free energy + heat energy d. kinetic energy = kinetic energy + free energy

  9. Which one of the following processes is endergonic? • the synthesis of glucose from carbon dioxide and water • the release of heat from the breakdown of glucose • the breakdown of glucose to power ATP formation • the burning of wood

  10. III. ATP: the main energy carrier Reasons why ATP is such a good energy carrier 1. Small • easily stored • mobile 2. Easily regenerated 3. Energy transferred • phosphorylation 4. Energy transferred is roughly the amount needed

  11. III. ATP: the main energy carrier (e.g. digestion) Loss of heat energy!!!!

  12. III. ATP: the main energy carrier Work of the Cell

  13. In RS, the potential energy of glucose is converted into the potential energy of ATP which can then be hydrolyzed to provide free energy for cellular work. Photosynthesis and respiration Glucose = potential energy PS: anabolic RS: catabolic They are coupled reactions! The products of ps are the reactants of rs.

  14. Which of the following is NOT a reason why ATP is such • a good energy carrier? • ATP is small and thus easily stored • ATP is easily regenerated • The energy from ATP can be transferred • ATP converts potential energy into free energy • The energy released by ATP is roughly equivalent to • that which is needed.

  15. Which of the following is NOT a correct statement? • Photosynthesis and respiration are coupled reactions • Photosynthesis is anabolic and respiration is catabolic • The products of respiration are the reactants of • photosynthesis • d. Plants do both photosynthesis and respiration

  16. IV. Enzymes Facilitate metabolic reactions Neutralize toxins Enzymes work by lowering the energy barrier required for reactions to take place. (substrates) Many reactions would go without enzymes, but would use too much energy and take too much time.

  17. IV. Enzymes A. Enzyme structure and function Catabolic or anabolic? Hydrolysis or dehydration synthesis? (- ase ending)

  18. Enzyme control and inhibition Feedback inhibition site Feedback inhibition

  19. Effect of temp and pH on enzyme activity Enzymes are denatured at high temperature and high and low pH.

  20. What do enzymes NOT do? • Use potential energy to break chemical bonds • Convert products into reactants • Convert reactants into products • Lower the activation energy required for chemical • reactions to go. • e. Detoxify toxins

  21. Which of the following conditions does NOT result in enzyme denaturation? a. very high temperature away from optimum b. very low temperature away from optimum c. very high pH away from optimum d. very low pH away from optimum

  22. An enzyme that is exposed to high heat far from its • optimum activation temperature experiences the breakage • of what type of bonds? • a. Covalent • b. Hydrogen • c. Ionic • d. Peptide

  23. V. Cell membranes: anatomy and physiology A. Membrane structure and function 1. main components: phospholipids and proteins Phospholipid bilayer Hydrophobic barrier ECF/ ICF (extracellular fluid/ intracellular fluid)

  24. 2. Fluid Mosaic Model

  25. Roles of proteins Self- antigens

  26. B. Movement across the membrane 1. passive transport: diffusion and osmosis2. active transport Solutes, solvents, solutions Movement of like species from area of high concentration to low [ ] Passive transport requires no energy Only requirement is for a [ ] gradient Facilitated diffusion uses transport proteins to effect passive transport of ions and polar molecules.

  27. 1. passive transport Osmosis = movement of a solvent from area of low [solute] to high [solute] across a differentially (selectively) permeable membrane Hypotonic, hypertonic, and isotonic solutions

  28. 2. active transport ATP Requires energy and protein pumps Movement is with disregard to the [ ] gradient

  29. Transport summary

  30. What does the phospholipids bilayer create? • a passage for polar substances into the cell • a hydrophilic environment to separate the ECF and ICF • a barrier to the movement of cholesterol • a hydrophobic barrier to the movement of charged • compounds

  31. What is always necessary for passive transport to take place? a. energy from ATP b. transport proteins c. ions or polar molecules d. a concentration gradient

  32. Under which of these conditions will water move into a cell? a. cell is in isotonic solution b. cell is in hypertonic solution c. cell is in hypotonic solution d. none of these

  33. 3. Cellular communication Signal transduction

  34. 4. Electron transport systems Electron donor Final electron acceptor

  35. The end

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