exam 1 bioenergetics/ ATP-PC system Flashcards
what is the 1st law of thermodynamics?
CONSERVATION OF ENERGY
- cannot be created or destroyed
- one form to another
what is the 2nd law of thermodynamics?
DISORDER
universe tends to move toward disorder
what is bioenergetics?
transfer and use of energy in biologic systems
what is entropy?
the disorder of components in a chemical system
what is enthalpy?
heat content in chemical reaction
if a reaction releases heat it is?
exothermic
if a reaction absorbs heat it is?
endothermic
both entropy and enthalpy are used in a mathematical equation to determine?
free energy
what can free energy determine?
whether or not a reaction can proceed spontaneously
what is gibbs free energy ^G?
change in free (available) energy
what does gibbs free energy ^G predict?
if a reaction will proceed and in what direction
*can turn energy into energy-rich compounds like ATP
if there is a net loss of energy and the reaction does proceed it is a + or a - ^G?
it would be a negative ^G and the reaction is EXERGONIC
if there is a net gain of energy and a reaction does not proceed would it be a positive or negative ^G?
positive ^G; energy must be added to make it proceed and the reaction is ENDERGONIC
when ^G is at zero what is happening?
reactants are at equilibrium
what is a constant number for a given reaction that tells us how much free energy is available under standard conditions?
standard free energy
what is a coupled reaction?
2 reactions happening at the same time; endergonic coupled with exergonic
- net ^G must be negative for reaction to occur
what is ATP?
the energy currency of the cell
when the bond between ATP’s phosphate groups is broken, large amounts of free energy are released, how much?
-7.3 kCal/mol
the energy available from ATP can be used for?
- coupling with endergonic reactions
- transport of molecules against a concentration gradient
- mechanical motion
at rest how much ATP do you consume every day?
40kg
during exercise how much ATP is used?
over 1 lb every minute
what does AMP concentration increase?
- ATP consumption
- decreased nutrients
- exercise
what is AMP?
activated protein kinase- regulatory enzyme
what does AMP do?
phosphorylates key enzymes
- increasing glucose transport
- suppressing energy requiring pathways
what does AMP inhibit?
glycogen synthesis
cholesterol synthesis
TAG synthesis
FA synthesis
what does AMP stimulate?
GLUT4- glucose transport glycogen breakdown glycolysis fat burning lipoprotein lipase (LPLm) activation
where is adenylate cyclase?
plasma membrane
adenylate cyclase stimulates an energy reaction which results in?
cyclic AMP (cAMP)
what does cAMP stimulate
a powerful enzyme- cAMP-dependent protein kinase, protein kinase A, PKA
what shuts down glycogen synthesis and activates glycogen breakdown?
glucagon
what are compounds with more free energy than ATP?
phosphoenolpyruvate-PEP -14.8 kcal/mol
creatine phosphate -10.3 kcal/mol
usually coupled with high endergonic reactions and may be used to create ATP
PCr is what?
phosphocreatine AKA phosphagen system or creatine phosphate system
where does the ATP-PC system take place?
mitochondria and cytosol
phosphocreatine PCr is what type of compound?
high energy compound
the ATP-PC reaction is what type of reaction?
a couple reaction that is a short duration in results in the fast replacement of ATP
-active muscle contraction and glycolysis
what is there more of in skeletal muscle than ATP?
10x PCr than ATP- its reservoir replenishes ATP
amount of creatine in skeletal muscle is relative to?
muscle mass
phosphocreatine supplies the phosphoric group for?
ATP synthesis
what are the enzyme and cofactor needed for the ATP-PC reaction to occur?
creatine kinase and magnesium
what does the ATP-PC system do?
make ATP or replenish PCr depending the direction of the reaction
what inhibits the ATP-PC pathway?
EXCESS product- high energy, high ATP or low PCr
what stimulates the ATP-PC pathway?
reactants- high ADP, high PCr
