Unit 9Cellular Respirationp. 119
Cellular RespirationUses the potential energy stored in the bonds of fuel molecules to produce ATPATP then used for cellular workFuel molecule- glucoseGlucose is broken down into water, carbon dioxide and energy (ATP)
C6H12O6 + 6O2 -- 6CO2 + 6H2O + Energy Label the names of the molecules.Label the reactants and the products in your lab manual.Which of the reactants and/or products will we measure today?
C6H12O6 + 6 O2 -- 6CO2 + 6H2O + Energy (ATP)
We can measure the rate of the reaction by measuring the
1. Oxygen consumptionQuantitative assay (test)reactant2. Carbon dioxide productionQualitative assayproduct
Third experiment- Alcoholic Fermentation
Form of anaerobic respirationYeast cells break down glucose to produce ATP in the absence of oxygenProcess used- glycolysisEnd product of glycolysis (pyruvate) is then reduced to either lactic acid or ethanol.Much of the bond energy is still contained in these waste products.We will study alcoholic fermentation Ethanol and carbon dioxide producedMeasure amount of carbon dioxide produced.
Exercise 9.1Oxygen consumption as a measure of metabolic rateMeasure the rate of respiration (oxygen consumption) of a mouse.Respiration chamberObserve the movement of a soap bubble in a tube as the mouse uses oxygen in the chamber
1. Place 25 g of KOH in bottom of chamber to absorb exhaled carbon dioxide. (Dont allow KOH to touch skin.)2. Instructor will weigh animal and place in chamber.3. Wet the inside of tube with water and place stopper in chamber. Seal the end of a tube with a drop of soap solution. You may have to work with this.4. Use a stopwatch to record the time it takes for the bubble to move a set distance along the tube. Record 5 time intervals.
Calculate metabolic rate for mouseRecord data in table 9.1
Final calculation is ml/O2/g/hFind an average for your five trials Compare to other groupsAlso, compare your metabolic rate to the rates for oxygen consumption in other animals (Table 9.2)Prepare the graph on the handout and include your mouse data. I will check graph before you leave.
Ex. 9.2Carbon dioxide production in plantsMeasuring reactants or products (of aerobic respiration)?Compare the production of carbon dioxide in peas- germinated germinated-boiled.
Set up flasks as described in manualBoil one set of peas, the other will not be boiled.Incubate for 1 hour. (make sure stopper is on tight)After 1 hour, place the tube in a tube of phenol red.Remove stopper from thistle tube and pour 100 ml of tap water in. (Flush collected gas into tube of phenol red.)Observe any color changes in the phenol red pH indicator.
Analysis of Ex 9.2Was this a quantitative or qualitative assay?In which set-up was carbon dioxide produced?
Structure of mitochondriaThe Krebs Cycle (citric acid cycle) and the electron transport chain take place in the mitochondria. View Figure 9.3 and the model of the mitochondrion in the lab.Identify these structures:Inner membraneOuter membraneCristaLocation of ATP synthase molecules MatrixKnow the structures in the sketch on p125 AND on the model set up in the lab.
Exercise 9.3 Fermentation in yeastFermentation is an anaerobic processOnly yields 2 ATP per glucose while aerobic respiration yields 36.In alcoholic respiration, the cells use glycolysis to produce ATP.The pyruvate molecules from glycolysis are reduced to ethanol.
1. Prepare 3 beakers with 0.5 grams of yeast and the appropriate glucose solution2. Let stand for 5 minutes.3. Transfer to a fermentation tube. Tilt tube to remove all the air from the neck.4. Incubate at 37 C. Measure CO2 production at 10 minute intervals.