Energy Production In Carbohydrates 1 Flashcards
What are the 4 stages of catabolism?
Breakdown of fuel molecules to building blocks molecules
Degradation of building block materials to a small number of organic precursors
Krebs cycle
Electron transport and oxidative phosphorylation
Briefly describe stage 1 of catabolism
Breakdown of fuel molecules to building block molecules
Short pathways
Breakage of C-N and C-O bonds
No energy released
Extracellular (GI tract)
Briefly describe stage 2 of catabolism
Degradation of building block materials to organic precursors
Many pathways Small fraction of energy released C-C bonds broken Cytosolic and mitochondrial Oxidative - release of reducing power (NADH) and some ATP Breakdown to metabolic intermediates
Briefly describe stage 3 of catabolism
Krebs cycle
Acetyl CoA oxidised to CO2
Small fraction of energy released
Mitochondrial
Single pathway
Briefly describe stage 4 of catabolism
Electron transporters and oxidative phosphorylation
Mitochondrial
Conversion of reducing power to ATP
NADH and FADH2 re-oxidised
O2 require (reduced to H2O)
What stage of catabolism does glycolysis occur?
Stage 2
What are the functions of glycolysis?
Oxidation of glucose
NADH production (2 per glucose)
Synthesis of ATP from ADP (2 ATP per glucose)
What are the features of glycolysis?
Central pathway of carb catabolism Occurs in all tissues Exergonic, oxidative C6 -> 2C3 Irreversible
What are the enzymes used in glycolysis?
- Hexokinase to convert glucose to glucose-6-P
- Phosphofructokinase-1 to convert fructose-6-P to fructose 1,6-bis-P
- Pyruvate kinase to convert phosphoenolpyruvate to pyruvate
Which step in glycolysis is the committing step?
Step 3
What kind of phosphorylation is in step 10?
Substrate level phosphorylation
What are the 3 types of lactose intolerance?
Primary lactase deficiency
Secondary lactase deficiency
Congenital lactase deficiency
What causes primary lactase deficiency?
Absence of lactase persistence allele
Only in adults
What causes secondary lactase deficiency?
Injury to small intestine (some diseases)
Occurs in infants and adults
Generally reversible
What causes congenital lactase deficiency?
Autosomal recessive defect in lactase gene
Very rare
