Energy and Metabolism Flashcards
Where does glycolysis, the Krebs cycle and Oxidative Phosphorylation take place within the cell?
Glycolysis- cytoplasm, Krebs Cycle- Matrix of Mitochondria, Oxidative Phosphorylation- cristae of mitochondria/ inner mitochondrial membrane
Define the terms glycogen, glycogenesis and glycolysis?
Glycogen- the stored form of glucose ( muscle and liver)
Glycogenesis- the formation of glycogen from sugar ( glycogen to glucose)
Glycolysis- the breakdown of glucose- into two molecules of pyruvate in the presence of 02 or into two molecules of lactic acid in the absence of 02
What are high energy phosphates?
Store molecules within the cell- rely on the transfer of phosphate groups from ATP.
High energy phosphate is ATP- adenine, ribose and three linked phosphates
Serves to couple the energy released from the breakdown of food- ATP
The phosphate-phosphate bond created when the compound adenosine triphosphate is formed.
Define aerobic and anaerobic?
Aerobic- in the presence of oxygen (oxidative phosphorylation)
Anaerobic- without the presence of oxygen
Discuss the function of glycolysis and what role does NAD play in glycolysis?
Glycolysis- a pathway used to transfer bond energy from glucose to re-join Pi and ADP to create ATP, and convert to either pyruvate or lactate
NAD is the hydrogen acceptor/ transporter
Discuss the operation of the Krebs cycle and the ETC in aerobic production of ATP
Krebs cycle combines Acetyl- CoA and oxaloacetic acid to form citrate.
Water molecule removed from the citric acid and NADH is reduced to NAD
ETC uses hydrogen to form ATP by coupling Pi to ADP
Primary role of the Kreb’s cycle is to complete the oxidation of substrates and form NADH and FADH to complete/ enter the ETC.
What is the function of NAD and FAD?
NAD and FAD are electron carriers to be used in the ETC
What is the efficiency of the aerobic degradation of glucose?
34% efficient, 66% lost due to heat
(Glycolysis- anaerobic- 33% efficiency)
What is the role of 02 in aerobic metabolism?
Oxygen acts as the final acceptor of H+ to form water- expelled via sweat
What are the rate limiting enzymes for the following processes: ATP-PC, Glycolysis, Kreb’s cycle and ETC?
ATP/PC= creatine kinase
Glycolysis= PFK (phosphofructokinase)
Kreb’s Cycle= isocitrate dehydrogenase
ETC= cytochrome oxidase
Discuss the relationship between LA and lactate?
Lactate is the conjugate base of lactic acid and lactic acid is produced in glycolysis.
ATP-PC system:
Site of Reaction: Sarcoplasm
Food Fuel used: Phosphocreatine (PC)
Controlling enzyme: Creatine Kinase
ATP YEILD : 1 mole of PC : 1 mole of ATP
PC— P + C + energy (exothermic)
Energy+ P + ADP— ATP (endothermic)
No bi-products
Very High Intensity
2-10 seconds
Glycolytic system:
Sarcoplasm
PFK and LDH (phosphofructokinase)
1 mole of glycogen: 2 moles of ATP
Lactic acid bi- product
High Intensity
Up to three minutes
Aerobic System:
Aerobic glycolysis- PFK breaks down glycogen and pyruvic acid in the presence of oxygen inhibits lactic acid production= 2ATP produced.
Krebs cycle- Matrix of mitochondria, Acetyl C o A creates citric acid , this is oxidized and hydrogen is removed= bi-product of carbon dioxide, 2ATP produced.
Citric acid created due to combining with oxaloacetic acid.
Electron Transport Chain- Cristate of mitochondria, 34 ATP released, Aerobic
Sarcoplasm, Matrix and Cristae folds of mitochondria
Glycogen and FFA’s
PFK, Acetyl CoA enzyme, Lipase
1: 38- Bi products of CO2 and H2O at low/ moderate intensity for 3+ mins
(Cytochrome oxidase)
What is the name for aerobic production of ATP?
Oxidative Phosphorylation- occurs in the mitochondria due to a complex reaction between the Krebs cycle and the ETC.
