Lecture 16 Flashcards
metabolic pathways
series of chemical rxns whereby the products of onercn are the substrates for the next rxn etc.. till the end product is generated
catabolism vs anabolism
cata= breakdown, release of E ana= build up, net input of E
cata/ana steps
cata= complex–> simple (ADP+ Pi —> ATP)
ana = simple –> complex (ATP —>ADP+ Pi )
catabolism order of steps
1- proteins, NA, polysac, complex lipid
2- Monomers- AA, Nuctides, Sugars, FA, glycerol
3- Metabolic intermediates- pyruvate, Acetyl-coa, CAC int
4- net output- energy+ small molecules- h2o, co2, nh3
anabolism order of steps
1- net input- energy+ small molecules- h2o, co2, nh3
2- Metabolic intermediates- pyruvate, Acetyl-coa, CAC int
3- Monomers- AA, Nuctides, Sugars, FA, glycerol
4-proteins, NA, polysac, complex lipid
Cellular respiration
is the liberation of energy through the oxidation of food.
how many oxidation states of carbon?
9
Formal charge #
the higher the ox # the more oxidizied
-1 for each bond to hydrogen
0 for each bond to carbon
+1 for each bond to O, N or S
alkane ox #
-4 –> most reduced
alcohol ox #
-2
aldehyde ox #
0
carboxylic acid ox #
+2
CO2 ox #
+4 –> most oxidized
molecules with more reduced carbons yield more energy upon oxidation
methane= most reduced= most energy
why CO2 can’t be burned–> end product
Why is ATP
the most widely used energy
currency of the cell?
• Hydrolysis yields lots of energy: – ATP + H2O ADP + Pi – ∆G0’= -30.5 kJ/mol (-7.3 kcal/mol) – Phosphoryl group has high transfer potential – Hydrolysis of ATP is favored because • Relief of charge repulsion • Resonance stabilization • Ionization and Solvation of ADP
hydrolysis of ATP
ATP4- + H2O —> ADP3- + P2-i + H+
NADH is the most widely
used electron carrier in cells
reducing power
Importance of coupling reactions:
• Problem: Virtually all synthetic reactions are
endergonic and cannot proceed as written.
(endergonic– need E to go to the right)
• Solution: Couple an endergonic reaction to an
exergonic reaction such that the overall reaction is
exergonic.
Coupling Reactions
The overall ∆G of a coupled series
of reactions = sum of the ∆G’s for the individual
reactions.
∆G of Pi + glucose —> glucose-6-P + H2O
+13.8
endergonic
∆G of ATP + H2O —> ADP + Pi
-30.5
exergonic
Coupling reactions to synthesize Glucose-6-
Phosphate from glucose and ATP
overall = ATP + glucose —> ADP + glucose-6-P
+13.8 - 30.5 = -16.7
What is Glycolysis?
• Uses Glucose:
– Corn syrup, sucrose, starch, glycogen
– Primary source of energy for the brain
– Fuels quick bursts of activity in muscle
• 10 reactions
• Takes place in the cytoplasm of a cell.
• The oxidation of glucose to pyruvate, NADH
and ATP.
Source of energy during a sprint:
- Pre-existing ATP
- Phosphocreatine via creatine
kinase - Glucose via glycolysis
- Glucose via glycolysis and
respiration
