Biology 105 Chapter 8: How cells make ATP Pgs Chapter 8: How cells make ATP Pgs

Student Outcomes  Give an overview and analysis of the 4 stages of aerobic respiration  Describe the process by which the proton gradient drives ATP synthesis  Give an overview and analysis of the 4 stages of aerobic respiration  Describe the process by which the proton gradient drives ATP synthesis

Student Outcomes  Summarize how the products of protein and lipid catabolism enter the same metabolic pathway that oxidizes glucose.  Describe the energy captured in each state of aerobic respiration.  Summarize how the products of protein and lipid catabolism enter the same metabolic pathway that oxidizes glucose.  Describe the energy captured in each state of aerobic respiration.

Respiration Organismic respiration - process of gas exchange between body and the environment. Cellular respiration - process of converting food energy to chemical energy Organismic respiration - process of gas exchange between body and the environment. Cellular respiration - process of converting food energy to chemical energy

Cellular respiration Two types: Aerobic - requires oxygen Anaerobic - absence of oxygen, includes fermentation Both types are exergonic reactions (release free energy) Two types: Aerobic - requires oxygen Anaerobic - absence of oxygen, includes fermentation Both types are exergonic reactions (release free energy)

Stage 1 of aerobic respiration of glucose Known as glycolysis Takes place in the cytosol Glucose molecule is converted to two 3- carbon molecules of pyruvate ATP and NADH are formed Known as glycolysis Takes place in the cytosol Glucose molecule is converted to two 3- carbon molecules of pyruvate ATP and NADH are formed

Stage 1 of aerobic respiration of glucose cont.  Glycolysis can occur in either aerobic/anaerobic conditions  Glycolysis has 2 phases  Glycolysis can occur in either aerobic/anaerobic conditions  Glycolysis has 2 phases

Glycolysis  1st phase  requires energy (ATP) - endergonic reactions. (energy investment phase)  A phosphate is transferred from ATP to the sugar. (phosphorylated)  1st phase  requires energy (ATP) - endergonic reactions. (energy investment phase)  A phosphate is transferred from ATP to the sugar. (phosphorylated)

Glycolysis formula  Glucose + ATP -> 2 G3P + 2 ADP ATP- Adenosine Triphosphate ADP- Adenosine Diphosphate G3P- glyceraldehyde-3-phosphate  Glucose + ATP -> 2 G3P + 2 ADP ATP- Adenosine Triphosphate ADP- Adenosine Diphosphate G3P- glyceraldehyde-3-phosphate

Glycolysis  2nd phase- (energy capture phase)  Each G3P is converted to pyruvate (a 3 carbon compound)  2 NADH and 4 ATP molecules are produced per glucose molecule.  2G3P + 2NAD +4ADP -> 2 Pyruvate + 2NADH + 4 ATP  2nd phase- (energy capture phase)  Each G3P is converted to pyruvate (a 3 carbon compound)  2 NADH and 4 ATP molecules are produced per glucose molecule.  2G3P + 2NAD +4ADP -> 2 Pyruvate + 2NADH + 4 ATP

Formation of acetyl Coenzyme A (CoA)  2nd stage  Takes place in the mitochondria  NAD+ gains an electron and becomes ‘reduced’ to NADH  2 additional NADH are formed per glucose molecule  2 CO 2 molecules are produced  2nd stage  Takes place in the mitochondria  NAD+ gains an electron and becomes ‘reduced’ to NADH  2 additional NADH are formed per glucose molecule  2 CO 2 molecules are produced

Citric Acid Cycle 3rd stage - also known as the Krebs cycle (founder Hans Krebs) Takes place in the mitochondria 3 molecules of NADH, 1 FADH 2 and 1 ATP are formed from each acetyl CoA molecule. Two CoA molecules were formed after the 2nd stage. This results in double the products. 3rd stage - also known as the Krebs cycle (founder Hans Krebs) Takes place in the mitochondria 3 molecules of NADH, 1 FADH 2 and 1 ATP are formed from each acetyl CoA molecule. Two CoA molecules were formed after the 2nd stage. This results in double the products.

ATP synthesis  4 ATP produced so far  2 ATP net in glycolysis  2 ATP in the citric acid cycle  4 ATP produced so far  2 ATP net in glycolysis  2 ATP in the citric acid cycle

Electron transport chain  4th stage - takes place in the mitochondria  Results in chemiosmosis - formation of ATP as protons diffuse through transmembrane channels.  This process is known as oxidative phosphorylation  Results in ATP formed  4th stage - takes place in the mitochondria  Results in chemiosmosis - formation of ATP as protons diffuse through transmembrane channels.  This process is known as oxidative phosphorylation  Results in ATP formed

Body Heat  Most heat generated by a warmblooded organism (and some others) is through heat generated as a byproduct of the electrons moving down the electron chain. Acceptor molecules are reduced and oxidized creating small amounts of heat!

Total ATP  ATP produced by one molecule of glucose in aerobic respiration.  36 in muscle, brain cells due to more energy needed to perform the 4 stages. Loss of 2 ATP’s  ATP produced by one molecule of glucose in aerobic respiration.  36 in muscle, brain cells due to more energy needed to perform the 4 stages. Loss of 2 ATP’s

Other Energy sources  Fatty acids and amino acids  1 glucose molecule = ATPs  1 Lipid molecule = 44 ATPs  Fatty acids and amino acids  1 glucose molecule = ATPs  1 Lipid molecule = 44 ATPs

Anaerobic Respiration  Does not use oxygen  Electrons are transferred as glucose is broken down to NADH.  Does not use oxygen  Electrons are transferred as glucose is broken down to NADH.

Fermentation  No electron transport chain stage.  Ethyl Alcohol or lactate (lactic acid) are produced as a byproduct (toxic to cells)  Lactate is used to make yogurt, sauerkraut and Kimchee.  2 ATP’s produced from 1 molecule of glucose.  No electron transport chain stage.  Ethyl Alcohol or lactate (lactic acid) are produced as a byproduct (toxic to cells)  Lactate is used to make yogurt, sauerkraut and Kimchee.  2 ATP’s produced from 1 molecule of glucose.

Lactate  3 carbon compound  80% regenerated into glucose by the liver.  20% is metabolized in the muscle cells if oxygen is present. (this is why heavy breathing occurs for a short time after activity)  3 carbon compound  80% regenerated into glucose by the liver.  20% is metabolized in the muscle cells if oxygen is present. (this is why heavy breathing occurs for a short time after activity)

Lactate fermentation  Short bursts of energy  Once believed that the accumulation of lactate (lactic acid) in the muscle cells results in muscle cramps, fatigue and pain  Short bursts of energy  Once believed that the accumulation of lactate (lactic acid) in the muscle cells results in muscle cramps, fatigue and pain

Creatine Phosphate  CP - Found in muscle cells and aids in the formation of ATP from ADP  Has short energy span 1-10 seconds, but will regenerate every 2-3 minutes  CP - Found in muscle cells and aids in the formation of ATP from ADP  Has short energy span 1-10 seconds, but will regenerate every 2-3 minutes

Energy use  1 second to 10 seconds (Anaerobic and CP)  10 seconds to 1 minute (Anaerobic)  1 minute - 4 minutes (Anaerobic/Aerobic)  4 minutes + (Aerobic)  1 second to 10 seconds (Anaerobic and CP)  10 seconds to 1 minute (Anaerobic)  1 minute - 4 minutes (Anaerobic/Aerobic)  4 minutes + (Aerobic)