Carbohydrate Metabolism Flashcards
(22 cards)
Glycolysis name
Embden-Myerhoff pathway
Glycolysis reaction
1 glucose -> 2 pyruvate + 2 NADH + 2 ATP
Glycolysis
- Occurs in cytosol
- 10 reactions
- Substrate level phosphorylation
Fate of pyruvate in aerobic condition
Pyruvate + CoA + NAD+ -> Acetyl CoA + CO2 + NADH
Enzyme: pyruvate dehydrogenass
Fate of pyruvate in anaerobic condition
Pyruvate + NADH Lactic acid + NAD+
Enzyme: Lactate dehydrogenase
Tissue in which end product of glycolysis does not proceed to aerobic respiration
Muscle
Cori cycle
Cycling of lactate between muscle and liver
• Lactate in muscle transported to liver
• Liver converts it to glucose
• Glucose reenters bloodstream, used by muscle
Krebs cycle location
Matrix of mitochondria
Krebs cycle function
- Further oxidation of acetyl CoA
* Produce energy as ATP or as NADH and FADH2, which are oxidised by ETC to produce ATP
Reactions of TCA
• Acetyl CoA combines with oxaloacetate to form citrate
For each acetyl CoA that enters cycle,
• 3 NADH and 1 FADH2 are produced
• 1 ATP formed by substrate level phosphorylation
• 2 CO2 released
Gluconeogenesis
Synthesis of glucose from non-carbohydrate compounds
Gluconeogenesis location
Liver, kidney (NOT muscle)
Cytosol, mitochondria of cells
Glycogen synthesis and degradation location
Liver, muscle
Cytosol of cells
Glycogen synthesis enzymes
- Hexokinase/glucokinase
* Glycogen synthase branching enzyme
Glycogenolysis enzymes
- Glucose 6-phosphatase
* Glycogen phosphorylase debranching enzyme
Pentose phosphate pathway name
Hexose monophosphate shunt
Pentose phosphate pathway location
Cytosol of cells
Pentose phosphate pathway function
- Oxidation of glucose, but not for energy
- Produce NADPH for synthesis of fatty acid, cholesterol
- Produce ribose-5-phosphate for nucleotide, nucleic acid synthesis
Pentose phosphate pathway enzymes
1st step of oxidatice phase catalysed by glucose-6-phosphate dehydrogenase
Liver glycogen function
Maintain blood glucoss
Muscle glycogen function
Provide glucose 6-phosphate for muscle energy requirements (intermediate in glycolytic pathway)
Organs without glucose-6-phosphatase
Kidneys and muscle
