Metabolism and Nutrition

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Metabolism and Nutrition
2012-04-07 18:24:27
Metabolism Nutrition

Metabolism and Nutrition
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  1. Metabolism
    • All chemical reactions that occur in the body
    • An energy balancing act between catabolic & anabolic reaction
  2. Catabolism
    • Chemical reaction that breaks down complex organic molecules into simpler ones
    • Occur in glycolysis, Krebs cycle, electron transport chain
  3. Produce more energy than they consume
    Exergonic Reaction
  4. Anabolism
    Chemical reaction that combine simple molecules to form more complex structures
  5. Consume more energy than they produce
  6. Molecule that participates most often in energy exchanges
    in living cells
    ATP (Adenosine Triphosphate)
  7. Oxidation
    • Removal of electrons resulting in decrease in potential energy
    • Involveloss in hydrogen atom
    • Also called Dehydrogenation Reactions
    • Example: lactic acid to pyruvic acid
  8. Reduction
    • Addition of electrons resulting in increase in potential energy
    • Example: pyruvic acid to lactic acid
  9. Oxidation-Reduction aka Redox Reactions
    • Redox eactions always in couples
    • One substance is oxidized another is simultaneously reduced

    • Example: Lactic acid is oxidized to form pyruvic acid.
    • The two hydrogen atoms removed are used to reduce NAD+
  10. Phosphorylation
    Addition of phosphate group to a molecule Increases potential energy
  11. Substrate Level Phosphorylation
    • Generates ATP by transferring high energy phosphate group from an intermediate directly to ADP
    • Process occurs in cytosol
  12. Oxidative Phosphorylation
    • Removes electrons and passes them thru a series of electron acceptors to molecules of oxygen
    • Occurs in mitochondrial membrane of cells
  13. Photophosphorylation
    Occurs only in plant cells or certain bacterial that contain light absorbing pigments
  14. ____ is the body’s preferred source for synthesizing ATP
  15. Turn glucose into glycogen
  16. The body uses glucose in the following ways
    • ATP Production
    • Amino Acid Synthesis
    • Glycogenesis
    • Triglyceride Synthesis
  17. Glycogenesis
    • Turn glucose into glycogen
    • Glucose monomers combined to form the polysaccharide glycogen
    • Performed by hepatocytes & muscle fibers
    • Capacity is 125 grams in liver, 375 grams in skeletal muscles
  18. Lipogenesis
    • Synthesis of triglycerides
    • Takes place when other glycogen storage areas are filled up
    • Hepatocytes transform glucose to glycerol & fatty acids used for lipogenesis
    • Triglycerides are deposited in adipose tissue
    • Storage capacity for adipose tissue is unlimited
  19. Oxidation of glucose produce ATP
    Cellular Respiration
  20. Four steps for cellular respiration
    • Glycolysis
    • Formation of Acetyl Cozenzyme A
    • Krebs Cycle aka Citric Acid Cycle aka Tricarboxylic Acid (TCA) Cycle
    • Electron Transport Chain
  21. Glycolysis
    • 1 glucose molecule is oxidized forming 2 pyruvic acid
    • Occurs in cytosol
    • Consumes two ATP but produces four (Netgain of 2 ATP)

    • Fate of pyruvic acid depends on oxygen availability
    • If oxygen is scarce, lactic acid forms
    • If oxygen is plentiful, acetyl coenzyme A is produced
  22. Krebs Cycle
    • aka Citric Acid Cycle aka Tricarboxylic Acid (TCA)
    • Cycle
    • Series of oxidation reduction reactions in mitochondria
    • Reduced coenzymes are NADH+ & FADH2
    • Glucose forms 2 pyruvic acid & 6 CO2
    • CO2 diffuse out of mitochondria into blood
    • Exhaled by lungs
  23. Electron Transport Chain
    • Takes place in inner mitochondria membrane
    • Exergonic reactions take place to produce ATP
  24. A polysaccharide that is the ONLY stored form of carbohydrate in the body
  25. Glycogenolysis
    • Splitting of glycogen into glucose
    • When ATP is needed, glycogen storedin hepatocytes are broken down into glucose
  26. Gluconeogensis
    • Glucose from catabolizing triglycerides (fats)
    • Forming of glucose from non-carbohydrate sources
  27. Lipid & protein combo produced by liver & intestine to be made water soluble
  28. Proteins in outer shell
    Apoproteins (apo)
  29. Four Major Classes of Lipoproteins
    • Chylomicrons
    • Very Low Density Lipoproteins (VLDLs)
    • Low Density Lipoproteins (LDLs)
    • High Density Lipoproteins (HDLs)
  30. Chylomicrons
    Transport dietary (ingested) lipids to adipose tissue
  31. Very Low Density Lipoproteins (VLDLs)
    • Form in hepatocytes
    • Contain mainly endogenous lipids
    • Converted to LDLs when deposit triglycerides in adipose cells
  32. Low Density Lipoproteins (LDLs)
    Carry 75% of total cholesterol in blood

    • When present in excessive numbers deposit cholesterol around arteries forming plaque
    • “bad cholesterol”

    • Some have too few LDL receptors
    • Body remove LDL from blood less efficiently
  33. High Density Lipoproteins (HDLs)
    • Prevents accumulation of cholesterol in blood
    • Remove excess cholesterol from cells & blood Transport them to liver for elimination
    • Dubbed “good cholesterol”
  34. Lipolysis
    • The breakdown of lipids (lipid catabolism)
    • Splitting of triglycerides into glycerol & fatty acids
    • Hydrolysis of triglycerides forms free fatty acids
    • For muscle, liver, & adipose tissue to oxidize fatty acids
  35. Lipogenesis
    • Synthesis of lipids from glucose or amino acids
    • Occurs when more calories are needed to satisfy ATP needs
    • Lipid Anabolism
  36. During digestion, proteins are broken down into ______
    amino acids
  37. Proteins are warehoused in the body
    True or False?

    • Amino acids are
    • * Oxidized for ATP
    • * Used to synthesize new proteins for body grown & repair

    Unlike carbs or trigercerides which are warehoused
  38. Deamination
    • Removal of amino group (NH2)
    • Occurs in hepatocytes
    • Produces highly toxic ammonia (NH3)
    • Liver cells convert ammonia to less harmful urea
  39. Amino acids must be _____ in order to enter Krebs Cycle
  40. Converting amino acids into glucose
  41. Conversion of amino acids into fatty acids
  42. Conversion of amino acids into ketone bodies
  43. Protein Anabolism
    • Formation of peptide bonds to produce new proteins
    • Carried out in ribosomes
    • Directed by RNA & DNA
    • Protein is main component of most cell structures
    • Adequate diet essential during growth, pregnancy, tissue damage
  44. There are _____ of amino acids in the human body.

    How many are essential & nonessential?
    • 20 amino acids
    • 10 essential
    • 10 nonessential
  45. Essential Amino Acids
    Amino acids not synthesized in body
  46. Nonessential Amino Acids
    Amino acids synthesized in body
  47. Transamination
    Transfer of amino group from amino acid to pyruvic acid or acid in Krebs cycle
  48. A Complete Protein
    Contains sufficient amounts of all essential amino acids

    Examples: Beef, fish, poultry, eggs, milk
  49. An Incomplete Protein
    Does not contain all essential amino acids

    Examples: Leafy greens, legumes, grains
  50. Form of energy measured as temperature and expressed in calories
  51. Amount of heat required to raise the temperature of 1 grams of water 1°C
    calorie (cal)
  52. Calorie (Cal) aka kilocalorie (kcal)
    • Equal to 1000 calories
    • More often used to measure’s body’s metabolic rates
  53. Metabolic Rate
    • Overall rate at which metabolic reactions use energy
    • Some used to produce ATP
    • Some is released as heat
  54. Basal State
    • Standard condition for measuring metabolic rate
    • Body in quiet, resting, fasting condition
    • Measurement obtained here is Basal metabolic Rate (BMR)
  55. Temperature in body structures deep to the skin & subcutaneous layer
    Core Temperature
  56. Temperature near body surface in skin & subcutaneous layer. It is usually 1 to 6°C lower than core temperature
    Shell Temperature
  57. Cholesterol
    • Organic chemical substance classified as a waxy steroid of fat
    • Essential structural component of mammalian cell membranes
    • Insoluble in blood
    • Transported in the circulatory system via lipoproteins
  58. Condition where artery wall thickens as a result of the accumulation of fatty materials
  59. Define the following...

    Glycolysis - First step in cellular respiration.

    Glycogenesis - Turn glucose into glycogen

    Glycogenolysis - Splitting up glycogen into glucose

    Gluconeogensis - Amino acids into glucose

    Lipolysis - Breakdown of lipids. Causes triglycerides to break down into glycerol & fatty acids

    Lipogenesis - Amino acids into fatty acids (triglycerides)