bioenergetics and reg of metabolism

  1. open systems
    exchange E and matter w/ environment n the form of mech work or heat E or matter which is food consumption
  2. closed systems
    no exchange of w/environment. Internal E is the sum of all diff interactions between and w/in a system
  3. bioenergetics
    E states in bio systems
  4. changes in free E
    provide info about chem rxns and can predict whethr a chem rxn is favorable and will occur
  5. whether a chem rxn proceeds is determined by the degree which enthalpy an entropy change durin a chem rxn
  6. enthalpy
    measure of overall change in heat of a sys during a rxn
  7. gibbs free E equation
    • AG=AH-TAS
    • spontaneous - loss of E and negative AG go to right
    • nonspon - gain E and positive AG go to left
  8. biochem rxns work well under standard states except PH, so a modified state needs to be made
  9. ATP is formed from substrate level and oxidative phosphorylation
  10. ATP cleavage
    • transfer of high E phos from ATP to another molecule
    • the phosphoryl group transfers will be determined by taking the sum of the free energies of the individual rxns
  11. half reactions
    components to determine the # of e- transferred
  12. peptide horm
    rapidly adjust the metabolic processes of cells via 2n mess cascades
  13. AA derivative
    long range effects by exerting regulatory actions at transcript level
  14. insulin
    pep horm secreted by beta cells of the pancreatic islets of Langerhans
  15. glucose is abs by periphera tissues via facilitated trans mech that utilize glucose transporters in cell mem. the tissues that need insulin to effectively uptake glucose is adip and skeletal
  16. 5 types of tissue insulin doesn't effect glucose uptake
    • nervous
    • kidney
    • intestinal mucosa
    • RBC
    • beta cells of pancreas
  17. glucagon is a pep horm secreted by alpha cells of pancreatic islets of Langerhans. It acts as second messengers to cause 4 effects
    • increased liver glycogenolysis
    • increase liver gluconeogesis
    • increase liver ketogenisis
    • increase lipolysis in the liver
  18. how glucagon acts as second messengers to cause an increase in liver glycogenolysis
    gluca activates glycogen phosphorylase and inactivates glycogen synthase
  19. how glucagon acts as second messengers to cause an increase in liver gluconeogenesis
    • gluca promotes conversion of pyruvate to phosphenolpyruvate by pyruvate carbox and PEPCK
    • increases conversion of F6P by F16BP
  20. how glucagon acts as second messengers to cause an increase in liver ketogenesis
    decreased lipogenesis
  21. how glucagon acts as second messengers to cause an increase in liver lipolysis
    gluca activates horm sensitive lipase in liver
  22. hypoglycemia
    • low blood sugar
    • gluca secretion
  23. hyperglycemia
    • high BS
    • inhibitor of gluca
  24. enzymes phos by gluca are dephos by insulin and vice versa
  25. glucocorticoids
    • from adrenal cortex and are part of stress response
    • glucose rapidly mobilized from liver to fuel actively contracting muscles during stress (cortisol)
  26. cortisol
    • steroid horm
    • promotes mobilization of E stores through degradation and increase delivery if aa and increased lipolysis
  27. cortisol elevates Blood gluc levels and increase gluco availability for nervous tissue through 2 mech
    • inhibit gluc uptake in most tiss and increase hepatic output of gluco via gluconeogenesis
    • enhances activity of gluca, epine, an catecholamines
  28. catecholamines are secreted by adrenal medulla and are adrenaline and noradrenaline
  29. function of catecholamines
    • increase activity ofliver nd muscle glycogen phosphorylase and promote glycogenolysis
    • act on adipose to increase lipolysis by inreasing horm sens lipase
  30. thyroid hormo increase basal metab rate based on increased O2 consumption and heat production when they are secreted
  31. metabolic rate produced by T4 occurs after latency of several hours but last for several days
    T3 produces more rapid meta rate but shorter duration
  32. Fuels of well fed and fasting states in: Liver, resting skeletal, cardiac, adipose, brain, RBC
    • W-glucose and AA F-FA
    • W-gluc F-FA and Ket
    • W-FA F-FA and Ket
    • W-gluc F-FA
    • W-gluc F-gluc
    • W-gluc F-gluc
  33. how does insulin impact carbo metab
    • increases uptake of gluc and increase carbo metab in muscle and fat
    • increased gluco in muscle is used as added fuel to burn during exercise and be stored as glycogen
    • insulin also increases glyco syn in liver by increasing activity of glucokinase and glycogen synthase and decrease the enzymes that promote glycogen breakdown
  34. how insulin affects AA
    increases aa uptake by muscle cells which then increase levels of pro syn and decrease break of essential pro
  35. 3 events insulin increases
    • gluc and tri uptake by fat cells
    • lipopro lipase activity which clears vldl and chlyomicrons from blood
    • triacyglycerol syn in adipose tissue and liver from acetyl coA
  36. 2 events that insulin decreases
    • triglycerol breakdown in adipose tissue
    • form of ketone bodies by liver
  37. 2 major fuel sources for skeletal muscles
    • gluc
    • FA
  38. insulin promotes gluco uptake in skeletal muscle which replenish glycogen storage and AA used for protein syn, glyco and AA can be oxi to be used for E
  39. when fasting,
    FA from free FA in blood are used by resting muscles
  40. Creatine phos 3 characters
    • short lived (seconds) E which transfers a phos from ADP to make ATP
    • skeletal use glyco and triacyglycerols
    • blood gluc and free FA are used
  41. cardiac myocytes prefer FA as major fuel and sometimes ketones are used during prolong fasting
  42. blood glucose is regulated to have enough/sufficient gluco for the brain
  43. brain, in hypogly, hypothalmic center in brain sense a fall in gluc level and release gluca and epine is triggered. FA cannot be used due to not being able to cross blood-brain barrier. The brain relies on glucose from hepatic glyconeolysis or gluconeogenesis. Longer fasting, brain depends on ketones
  44. respirometry
    • allow accurate measurng of respiratory quotient which is diff depending on organism
    • RQ=CO2 produced/O2 consumed
    • will change depending on setting
  45. calorimeters
    measure basal metabolic rate based on heat exchange with the environment
  46. carbo and pro mass remain stable over time, prolong starvation causes it to fluctuate
    lipids in adipose tissue are the primary factor for gradual change in body mass
  47. 2 characters of ghrelin
    • secreted by the stomach due to sight smell sound or taste of food
    • inceases appetite and stim release of orexin
  48. orexin
    • increases apetite and is involved in alertness and sleep wake cycle
    • **triggered nu hypoglycemia**
  49. leptin
    hormone secreted by fat cells that decrease apetite by supressing orexin production
Card Set
bioenergetics and reg of metabolism
bioenergetics mcat