Ch 8: Glucose Metabolism Flashcards
Metabolism
the sum of all chemical reactions in an organism
catabolism
the breakdown of input molecules converted to products
energy is usually produced and is stored in high energy aka ATP and NADH
anabolism
synthesis of complex molecules
energy is required
Gibbs Free energy
(G)
energy defined for constant temp and pressure
∆G
delta g
difference in energy btw reactants and products
∆G=Gproducts-Greactants
∆G^0
if reactants and products are at equilbrium, then ∆G^0 is used
neg value of ∆G
means process is favorable aka free energy is released, downhill, exergonic, spontaneous
pos value of ∆G
means process is unfavorable aka free energy is consumed, not spontaneous, unfavorable, uphill, and endergonic
units of energy
1 kcal/mol=4.17 kJoule/mol
ATP
non redox high energy compound
ATP+H2O–>ADP+Pi
ADP +Pi=more favorable and more stable bc of lower energy
∆G=-7.3 kcal/mol
NADH
redox high energy compound
∆G= -52.4
redox reactions
one substance transferring electrons to another substance
reduction
gain of electrons
oxidation
loss of electrons
reducing agent
gives up an electron
oxidizing agent
takes on electrons
redox rules (oxidation)
• Oxidation
o Product has 2 fewer H atoms than the substrate or product has 1 more oxygen atom than substrate
o Substrate is the more reduced form and product is the more oxidized form; product has two fewer electrons than substrate
o The two electrons given up by substrate are usually transferred to NAD+ to give NADH
• Ex: [NAD^+ +H3C-CH2OH+H2O→H3C-COH + NADH + H+]
Redox rules (reduction)
o Product has 2 more H atoms than the reactant or product has 1 fewer oxygen atom than reactant
o Substrate is the more oxidized form and product is the more reduced form; product has two more electrons than substrate
o The two electrons accepted by substrate have usually come from NADH to give NAD+
Cellular respiration equation
C6H12O6+6O2–>6CO2+6H2O+ free energy (-686 kcal/mol)
favorable
glycolysis
occurs in cytoplasm
generates no CO2
10 enzymatic steps
outcome: 2 pyruvate, 2 ATP, 2 NADH
Steps 1-3 of glycolysis
1) Phosphate (from ATP) converts to C6-OH of glucose
2) Carbonyl C1=O of glucose 6 phosphate moves to C2=O fructose 6phosphate
3) Phosphate (from ATP) to C1-OH of fructose-6 phosphate
Steps 4 and 5 of glycolysis
Break C3-C4 bond to get two 3 carbon phosphosugars
interconvert the two 3 carbon phospho-sugars
steps 6&7 of glycolysis
generate 2xNADH
generate 2x ATP
Steps 8&9
Make 2xPEP