glycolysis, gluconeogenesis, and the pentose phosphate pathway part 1: glycolysis chapter 14
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Glycolysis
– Chemistry of each glycolytic reaction: Forwards and Backwards.
– The general thermodynamics of each reaction.
– Other sugars entry to glycolysis.
– What to do with Pyruvate?
Key topics: Things to Know
Central Importance of Glucose
• Glucose is an excellent fuel– Yields good amount of energy upon oxidation– Can be efficiently stored in the polymeric form – Many organisms and tissues can meet their
energy needs on glucose only
• Glucose is a versatile biochemical precursor– Bacteria can use glucose to build the carbon
skeletons of:• All the amino acids• Membrane lipids• Nucleotides in DNA and RNA• Cofactors needed for the metabolism
Glycolysis Overall
1 Glucose 2 Pyruvates + 2ATP + 2 NADH
10 Reactions: Know them Backwards and
Forwards!!!!
Where is this going on in a cell?
EOC Problems 1+2 can be worked from this Figure and Lactate Dehydrogenase Rxn (slide 35)
Another View of Glycolysis
What is This??
from KEGG
Pathways Linked to Glycolysis, Enzymes by
EC numbers
Keep Track of those Carbons!
EOC Problem 9..checks out the carbons from triose-phoshpates! Think about the aldolase ΔG.
3-P-Gyld DH
EOC Problem 14 is about arsenic poisoning and what happens when arsenate is involved with this reaction.
A Fun Homework Problem
Add up all the ΔG’o ‘s and see how:
1. Aldolase’s endergonic ΔG is over come.
2. Total for Glycolysis…what enzymes are doing the work?
But, is that all…what about REALITY?
EOC Problem 10: A look at modifying Glycolysis, could it work?
Showed cancer cells had high rate of glycolysis, first to crystalize most glycolytic enzymes. Devised the first reliable, quantitative O2 uptake apparatus, lovingly called a Warburg!..but replaced by oxygen electrodes.
Nobel Prize, 1931
and trained 6 future Nobel Laureates!! One of which is Hans Krebs who worked out the Citric Acid Cycle.
Medical Aspect: CANCER
Most tumors: Glycolysis goes 10X faster than normal cells. And is mainly fermentative (producing lactic acid).
The strategy is to:
1. Use this in Detection
2. To slow glycolysis down in cancer cells.
Use of 6-Phospho-FdG in Positron Emission Tomography, it accumulates in regions of high glycolytic activity
See next slide
CT and PET Scans
Patient with malignant melanoma –ingested 6-Phospho-FdG
Left-CT scan –shows location of bone, soft tissue
Center-PET scan showing high glucose use.
Natural areas of high glucose use: brain but not bladder
Cancer has spread to liver, muscle Right –false color composite
Alcohol Fermentation
EOC Problem 4: Calculating the Keq of Alcohol Dehydrogenase (use Table 13-7)
EOC Problem 6: follow the carbons from glucose into ethanol.
Energetics of Glycerol as An Energy Source
Glycerol kinase - ATP
Glycerol-3-P DH + NADH
3-P-Gyld DH + NADH
3-PGA Kinase + ATP
Pyr Kinase + ATP
Total = 1 ATP + 2 NADH
Can GLYCEROL be FERMENTED? Explain
Commercial Ethanol Fermentation
EOC Problem 7…all about the heat released from fermentation…what’s going on?
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