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Unformatted text preview: Lab 5: Photosynthesis and Respiration Lab 5: Photosynthesis and Respiration Presentations Lecture Scenario Investigation descriptions Lab 5 Exam 1 Exam 1 Most of the questions were taken directly from the lab response sheets Answers to response sheets are posted every Friday Make sure you study before the exams If you received a low score, don’t panic, the lowest exam score is dropped! The average was 19.4 which is fairly consistent with the other sections Exam 2 is NEXT WEEK!!!! Exam 2 is NEXT WEEK!!!! Will be on labs 4 and 5. STUDY!!!!!! Photosynthesis & Respiration Respiration Photosynthesis Photosynthesis Most important biological energy reaction Plants, algae and some bacteria Defined as: Conversion of light energy into Defined chemical energy in the form of Glucose chemical Takes place in the chloroplasts with chlorophyll Photosynthesis takes carbon dioxide, water, and sunlight and creates glucose and oxygen 6H2O + 6CO2 6O2 light C6H12O6 +
Glucose Cellular Respiration Cellular Respiration
Glucose Pyruvate (pyruvic acid) GLYCOLYSIS
After glycolysis, there are two forms of respiration that can occur Aerobic Respiration (w/ oxygen) 36 ATP molecules!! Anaerobic Respiration (w/o oxygen) Fermentation incomplete breakdown of glucose only 2 ATP molecules per glucose Respiration Respiration
C6H12O6 + 6O2 ATP 6H2O + 6CO2 + 36 Respiration (cont.) Respiration Aerobic (O2 present)- glucose is broken down completely in the Krebs Cycle completely
Released energy from the Krebs Cycle is Released transferred (via NADH2 molecules) to the electron transferred transport system (ETS) transport ETS uses O as a final electron acceptor, producing 2 H2O (no harmful byproducts) and 36 ATP (more (no efficient, more energy) from 1 glucose molecule efficient, This takes place in the mitochondria (power house) Cellular Respiration Cellular Respiration AEROBIC – Krebs Cycle and ETC Start here 2 ATP 2 ATP 32 ATP
http://fig.cox.miami.edu/ Faculty/Dana/krebs.jpg Respiration (cont.) Respiration Anaerobic (no O2) - glucose is broken down via glucose glycolysis (in cytoplasm) into 2 pyruvate molecules and 2 ATP and Harmful byproducts: In animals pyruvate is converted into lactic acid (sore In muscles) muscles) In some microorganisms pyruvate is converted into alcohol In via fermentation via Both represent incomplete (inefficient) breakdown of Both glucose and produce only 2 ATP (energy) per glucose molecule molecule Cellular Respiration Cellular Respiration ANAEROBIC Fermentation
Start here Glucose Only 2 ATP! Pyruvate In animals and bacteria: Lactic Acid Not efficient enough for US! Without aerobic respiration, our metabolism would shut down Pyruvate In Yeast cells: Alcohol What you need to know What you need to know Glucose Anaerobic w/o oxygen Yeast: 2 Alcohol Animals and bacteria: 2 Lactic Acid fermentation Net: 2 ATP glycolysis 2 Pyruvate Aerobic w/ oxygen Krebs Cycle and Electron transport chain in the Mitochondria cellular respiration Net: 36 ATP Fun Facts about Yeast Fun Facts about Yeast Are in the Fungi kingdom Use glucose for energy Can create energy through cellular respiration (aerobic) or through anaerobic respiration (produces alcohol and CO2) In today’s investigations, we will be looking at yeast’s potential to do both of these and which substances are best for respiration Scenario: Global Warming Scenario: Top Graph - rise in CO2 levels at the south pole (Antartica) (Antartica) Bottom Graph - rise in Bottom CO2 levels at Mauna CO Loa, Hawai’i Loa, What gas is the most common green house What gas? gas? H2O & CO2. Water Vapor from evaporation & CO2 2. Water from emissions esp gasoline, factories from Is the deforestation of the rainforest Is contributing to the process of global warming? contributing YES! Destruction of the main sink for CO2 and burning of wood releases more CO2 burning Drive less, reduce electricity, etc What can you do to alleviate the problem? Carbon dioxide’s role in Photosynthesis Investigation 1 Investigation 1 Elodea in water enriched with CO2 What will happen to the carbon dioxide in the water? How can we tell what is going on? Carbon dioxide in the water forms carbonic acid slightly acidic Why is soda acidic? CARBONATION! We use phenol red as an INDICATOR (yellow = lower pH, red = neutral) Elodea in water enriched with CO2 Tube 1 – Pink – Positive control Tube 2 – Elodea – Experimental
Salmon/yellow to pink as CO2 is used up Carbon dioxide’s role in Photosynthesis Investigation 1 Investigation 1 Tube 3 – Salmon/yellow – Negative control Does Elodea Consume CO2? Does Elodea Consume CO
No CO2 1 3 CO2 2 Controls Exp + - Investigation 2 Investigation 2 Label tubes 13 with height measurements Tube 1 – yeast to 1st mark and water to top mark Tube 2 – yeast to 1st mark, water to middle mark and glucose to top mark Tube 3 – yeast to 1st mark and I will add the Sodium Azide to middle mark. Glucose to the top mark. Add 10 drops of phenol red immediately to all three tubes. Incubate check on color every 5 min. Record height of airspace in respirometers so you can see the amount of CO2 produced. Record changes in distance and color over 20 minutes Investigation 2: Fermentation vs aerobic respiration Investigation
Tube 1 5 mls 5 mls 5 mls water water Yeast sol Tube 2 glucose water Yeast sol Tube 3 glucose Sodium azide Yeast sol •Phenol red detects ? •Add 10 drops of phenol red to all 3 tubes 3 test tubes:
Yeast + Water Fermentation vs. Aerobic Respiration
1 Yeast + Water + Glucose 2 Yeast + Sodium azide + Glucose Anaerobic 3 Investigation 2 Investigation 2 Control Aerobic CAUTION! CAUTION! 3 test tubes:
Yeast + Water Fermentation vs. Aerobic Respiration
1 Yeast + Water + Glucose 2 Yeast + Sodium azide + Glucose Anaerobic less CO2 produced 3 Investigation 2 Investigation 2 Control - no/little CO2 produced Aerobic - CO2 produced Investigation 3 Investigation 3 Fill out using Table 5.3. Tube1 water and Glucose Tube 2 water and glycerol Tube 3 water and protein Add 5 ml of each plus 5 ml of yeast solution to tube then place in incubator check on the height of gas bubble every 15 minutes. Which substance(s) will supply yeast with fuel for cellular respiration?
• • • Respiratory Fuels Investigation 3 Investigation 3 Protein Glucose Glycerol (backbone of lipids) Measure respired CO2 Which tube will have the largest change in gas column? Table: 5-3 Co2 Accumulation and Color Tube Tube 1 2 3 Solution 1 Water Water Water Solution 2 Glucose Glycerol Protein 0 30 45 60 75 Computer exploration of Photosynthesis Investigation 4 Investigation 4 Click the icon on the desktop with the leaves… Follow instructions Adjust each variable to get the lowest value that maximized photosynthetic rate! Investigation Order Per Group Investigation Order Per Group
Label all respirometers and fermentation tubes with solution and group # Group 1: 2, 3, 4 Group 2: 3, 2, 4 Group 3: 4, 3, 2 Group 4: 3, 4, 2 ...
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