Carbohydrates II Flashcards
- Which tissue requires a lot of energy and therefore has a very high glucose consumption?
- Neural retina
- What outcome has an impaired glucose metabolism in rods?
- retinal degeneration
- What are the 4 processes in glucose metabolism (cellular respiration)?
Glycolysis: glucose > pyruvate
- Pyruvate oxidation: pyruvate > acetylCoA
- Citric Acid Cycle
- Oxidative phosphorylation > ETC
- What is glycolysis and where does it take place in a cell?
- The breakdown of glucose
- cytosol
- Does glycolysis require oxygen?
- Not a requirement, can happen as an aerobic or anaerobic process
- What is the input (needed) and output (products) of glycolysis?
- Investment of 1 glucose molecule, 2 ATP and 2 NAD+
- Output of 2 pyruvate, 2 net ATP and 2 NADH
- The cells of which organs regulate glycolysis?
Liver and skeletal muscle regulate glycolysis
- What are the start substrate and end product of the investment phase of glycolysis and which additional molecules are used or gained?
Start: glucose
molecules req: 2 ATP
End: 2 molecules of glyceraldehyde -3-phosphate (GADP)
- What are the start substrate and end product of the pay-off phase of glycolysis and which additional molecules are used or gained?
Starting: 2 molecules of GADP
molecules req: 2 ATP, NAD+
End: 2 pyruvate, 2 NADH and net gain of 2 ATP
- In which four molecules can pyruvate be converted under aerobic or anaerobic conditions?
- Aerobic
i. Convert into acetyl CoA to undergo TCA cycle - Anerobic
i. Lactic acid fermentation
ii. Alcoholic fermentation (yeast)
iii. Low glucose levels > gluconeogenesis
- What is gluconeogenesis (definition) and what is a synonym name for it?
The new synthesis of glucose from non-carbohydrate sources, initiated by pyruvate
- Synonym: endogenous glucose production (EGP)
- Which product is generated in gluconeogenesis but not produced in glycolysis?
oxalacetate
- Which substrates can be utilized in gluconeogenesis?
Non-carbohydrate carbon substrates
i. Glucogenic amino acids (proteins, glycerol and odd chain fatty acids)
ii. Lactate
- Under which oxygen condition occurs lactate fermentation?
- Anerobic (absence of oxygen)
- Which molecules are converted into the Cori Cycle and in which organs does it happen?
Anaerobic glycolysis produces lactate > transported into the liver to form glucose > returns to the muscle and goes through the cycle to produce lactate
- What is the second step in glucose metabolism?
- Pyruvate oxidation utilizes the pyruvate and bring it into the mitochondrion for cycling to produce acetyl CoA
- What is required (input) and what is generated (output) during pyruvate oxidation?
(1) molecule pyruvate molecule from glycolysis is used to generate (1) molecule of acetyl CoA
- Acetyl CoA can be obtained from which biomolecule components?
Protein, carbohydrates, and lipid metabolism
i. oxidation of pyruvate from glycolysis
ii. Oxidation of long chain fatty acids
iii. Oxidative degradation of certain amino acids
- Where in a cell takes pyruvate oxidation place?
- Mitochondrion
- What is the third event in glucose metabolism, where takes it place in a cell and what is the major purpose?
- Citric acid cycle (TCA) occurs in the mitochondrion and the purpose is to generate energy (ATP)
- What are the two start substrates in the citric acid cycle and what do they form?
- Oxaloacetate and Acetyl CoA are initiators of the TCA cycle and forms Citrate
- The neurotransmitter glutamate can be converted into which compound that is part of the TCA cycle?
- Alpha-ketoglutarate which binds to a coenzyme A and the NAD+ gets reduced
- What is the 4th event in glucose metabolism, which two parts does it contain, and where in a cell takes it place?
Oxidative phosphorylation (location: mitochondrion)
i. Electron transport chain
ii. Chemiosmosis
- What is generated in that last event of glucose metabolism and by which enzyme?
- High concentration of ATP via enzyme ATP synthase
