Anaerobic Respiration and Respiratory Quotient

Alternative Energy Sources Triglycerides (fats) are hydrolyzed into glycerol and then G3P (step 6 in glycolysis) Triglycerides (fats) are hydrolyzed into glycerol and then G3P (step 6 in glycolysis) Triglycerides (fats) are broken into 2-C units and bind with CoA  Acetyl-CoA Triglycerides (fats) are broken into 2-C units and bind with CoA  Acetyl-CoA Fats are great source of energy but take longer to breakdown Fats are great source of energy but take longer to breakdown More H atoms = more energy More H atoms = more energy – Energy density Proteins are broken into AA (lose their amino group) and then change into pyruvate or an intermediate step in the citric acid cycle Proteins are broken into AA (lose their amino group) and then change into pyruvate or an intermediate step in the citric acid cycle

Aerobic and Anaerobic Reactions Organism can be: Organism can be: – Strict anaerobes  can’t survive in oxygen – Strict aerobes  can’t survive without oxygen – Facultative aerobes  can survive with or without oxygen What parts of cellular respiration are aerobic/anaerobic? What parts of cellular respiration are aerobic/anaerobic? – Aerobic  Krebs cycle/Oxidative Phosphorylation – Anaerobic  Glycolysis Anaerobic Organism can still do glycolysis, but what is left at the end? Anaerobic Organism can still do glycolysis, but what is left at the end? – pyruvate Breaking down pyruvate after glycolysis creates different kinds of fermentation Breaking down pyruvate after glycolysis creates different kinds of fermentation

Fermentation Alcoholic  pyruvate is converted into ethanal and then ethanol (alcohol and fuel) Alcoholic  pyruvate is converted into ethanal and then ethanol (alcohol and fuel) – CH 3 CHO +2H +  C 2 H 5 OH Also releases CO 2 ; used to make bread/cakes raise Also releases CO 2 ; used to make bread/cakes raise Lactic Acid  pyruvate is converted into lactate by lactate dehydrogenase Lactic Acid  pyruvate is converted into lactate by lactate dehydrogenase Energy supply in muscles when oxygen runs low Energy supply in muscles when oxygen runs low Why is it dangerous to us? Why is it dangerous to us? – Builds up in cells and lowers pH (acidic) – Causes muscle crams and soreness after working out – Must be removed from the cells and broken down in the liver; 20% changed to CO 2 and H 2 O – Oxygen debt  O 2 needed to remove lactate

How Efficient Are Our Energy Sources? Respiratory Quotient  value based on the ratio of CO 2 made to O 2 used during respiration Respiratory Quotient  value based on the ratio of CO 2 made to O 2 used during respiration – Value also terms if anaerobic or aerobic respiration is occurring RQ = #mol CO 2 / # mol of O 2 RQ = #mol CO 2 / # mol of O 2 Glucose  6/6 = 1.0 Glucose  6/6 = 1.0 Olive Oil  36/51= 0.7 Olive Oil  36/51= 0.7 Protein  0.9 Protein  0.9 Fermentation: Fermentation: – Alcohol  <2 – Lactate  No value (no CO 2 made) RQ > 1; anaerobic respiration RQ > 1; anaerobic respiration 2 C 18 H 34 O O 2  36 CO H 2 O + Energy C 6 H 12 O 6  2 C 2 H 5 OH + 2 CO 2 + Energy C 6 H 12 O 6  2 C 3 H 6 O 3 +Energy

Measuring RQ Respirometer  sensitive device to measure O 2 consumption by an organism Respirometer  sensitive device to measure O 2 consumption by an organism What variables must we account for? What variables must we account for? – Temperature – Pressure – Activity level – CO 2 produced CO 2 is removed from the air by an absorbent chemical; KOH (aq) CO 2 is removed from the air by an absorbent chemical; KOH (aq) Drop in O 2 volume displayed with manometer fluid Drop in O 2 volume displayed with manometer fluid How can we measure CO2 production? How can we measure CO2 production?

Measuring RQ Remove CO 2 absorbing chemical to measure CO 2 Remove CO 2 absorbing chemical to measure CO 2 RQ = 1; the manometer wont move RQ = 1; the manometer wont move What is the energy source? What is the energy source? – Carbohydrates What does it mean if we see an increase in volume? What does it mean if we see an increase in volume? – More CO 2 produced – Moving into anaerobic respiration (RQ>1) What does it mean if we see a drop in volume? What does it mean if we see a drop in volume? – Less CO 2 produced – Moving to lipid/protein use (RQ<1)

Practice Problems A compound is burned inside a 1000ml bell jar and the air was analyzed before and after. After the reaction the data showed the amount of O 2 dropped 2.7% while the amount of CO 2 measured 4ml. What type of organic fuel is this compound? 1) A compound is burned inside a 1000ml bell jar and the air was analyzed before and after. After the reaction the data showed the amount of O 2 dropped 2.7% while the amount of CO 2 measured 4ml. What type of organic fuel is this compound? What would be the average RQ for an organism that divides it diet evenly between carbohydrates and fats? 2) What would be the average RQ for an organism that divides it diet evenly between carbohydrates and fats? Air is 21% O 2 Air is 21% O 2 21% in 1000ml of air  210ml 21% in 1000ml of air  210ml 2.7% of 210ml  5.67ml 2.7% of 210ml  5.67ml 4 ml/ 5.6 ml = 0.71  fatty acid 4 ml/ 5.6 ml = 0.71  fatty acid RQ of carbohydrates= 1.0 ; RQ of lipids  0.7 (1.0 x 0.5) + (0.7 x 0.5) = 0.85 (1.0 x 0.5) + (0.7 x 0.5) = 0.85

Homework Respiration review sheet Questions 15.8 and 15.9 in textbook Read pages Quizlet vocab Study for quiz on Ch. 16 next week