Lecture 19/20: The Energy Distribution System Flashcards
What is the medium of energy exchange in the cell?
Adenosine Triphosphate
How is ATP used in coupling reactions?
- fatty acid or amino acid oxidation
- coupling reactions are not efficient, 60% energy released lost as heat
- 40% used for biological work
- break phosphate bond to release energy
What metabolism provides most atp?
- glucose and fatty acid metabolism
- little from amino acids
What is NADH and FADH2?
- reducing agents produced by glycolysis, beta oxidation and kerb’s cycle
- supply protons and electron to ETC, where majority of ATP made
- actas fuel
Where is ATP made?
- some in glycolysis and kerbs cycle
- majority in ETC
How is ATP produced anaerobically
- no O2
- sometimes in muscle
- generated by phosphocreatine degradation (ATP buffer)
- ATP –> ADP + Pi
PCr + ADP + H+ –> ATP + Cr
(allows atp to be reproduced, donates phosphate group) - glycolysis, end product is lactate
- inefficient but very fast
***not useful if running marathon, more HIIT workouts
What are high energy phosphagens?
- ATP and PCr
- provide immediate energy, (depleted in 12-13 seconds)
What is creatine supplementation?
- increase muscle PCr content
- faster restoration of ATP
- Improves performance with repeated bouts of high-intensity excersise
- gains in muscle mass and strength w/ resistance training
How does gluocose boost effectiveness of Cr supplementation?
- creatin transport is insulin sensitive
- get inside cell because of transporter, the transport is insulin sensitive
- if creatin taking at same time as high dose of glucose causing much larger increase in creatin in body
- however not healthy
How/where is most energy stored?
as triglycerides in adipocytes
Where are carbohydrates stored?
- glycoen in liver (approx 150g)
- glycogen in muscle (approx 350 g)
- only about 30g off glucose in blood (not much)
What is significant about protein as energy storage?
- protein is a large potential energy source
- represents about 25000 kcal but protected
- used in starvation or caloric restriction
What are Pros/cons of carbohydrates as fuels?
- generate ATP faster than fat
- can also generate atp anaerobically (3x faster than aerobic)
- holds a lot of water “heaver” and less energy dense than fat
What are pros/cons of lipids as fuels?
- does not hold water, twice as energy dense as carbs
- represents must abundant energy reserve
- cannot provide energy anaerobically
How many calories in a pound?
3600 kcal in a pound of adipose tissue, most people expend 2000-2500 kal per day
How can you minimize loss of lean mass durng weight loss?
- can have 30-40% lean mass lost during weight loss
- can be minimized via:
- resistance training, resistance +higher protein intake
What is the absorptive state?
- first 3-4 hours after a meal
- energy (macronutrients) stored
- called anabolic state
- glycogen stored in liver and muscle
- triglycerides stored in adipose tissue, liver and muscle
- excess calories in form of glucose and amino acids get converted to fat
- nutrients: glucose, fatty acids, amino acids can get oxidized and stored
- Diagram on slide 13 lec 19/20**
What is the postabsorptive state?
- fasting
- stored macronutrients are mobilized for energy (catabolism)
- glucose spared for nervous system
- all fuels (protein,s triglycerides, glycogen can be mobilized for glucose)
- Diagram on slide 14 lec 19/20**
What is gluconeogensis
- muscle stores most glycogen, when it breaks down it is for own use not released into the body
Why is glucose maintained so tightly?
- many cells require glucose
- maintain osmotic balance
- hpyerglycemia cause glycosylation of amino acids in kidneys, peripheral nerves, lens of eye, causing damage
Glucose Regularion via Insulin
SLIDE 16 LOOK AT IT
-
What is glucagon
- counter hormone to insulin
- does opposite
- does not alter glucose uptake, but stimulates fat breakdown in adispose tissue
- slide 17
Explain substrate use during exercise?
** EXAM: subtrate use during exercse**
- mostly muscle glycogen, muscle triglycerides, plasma free fatty acids (FFA) and lastly plasma glucose
(above written in order)
- prolonged lower intensity relies on plasma derivdes substrates (free fatty acids0
- intense exercise, mainly muscle glycogen and some triglycerides
How is blood glucose maintained during exercise?
- maintained by liver
- glycogenolysis: breakdown of glycogen
- early exercise depletes liver glycogen by 50% in hour, 80% of total glucose output
- due to dec insulin, inc glucagon, inc catecholamines
- gluconeogensis: make new glucose
- later in excersise when liver glycogen is depleted and precursors (lactate, glycerol, pyruvate, alanine) become more abundant
- mainly due to dec insulin, inc glucagon, inc catecholamines
