Name: Date: Per: Enzymes Review & Using text to understand ATP & Cellular Respiration Read this: Digestive enzymes are protein-based biological catalysts that play important roles in our lives. They help remove stains from our shirts, turn milk into cheese, and are responsible for turning our dinner into use- able fuel for our bodies. Enzymes however do not work well universally. Some are meant to work at high temperatures, others at low temperatures. They may work best in acidic conditions or neutral conditions. In this activity we will look at the optimal conditions for two different enzymes. The digestive enzyme lipase is made in the pancreas and breaks down lipids in the small intestine, while pepsin breaks down proteins in the stomach. 1. Name the two enzymes illustrated in Model 1. From the Read this above, in which organ is each enzyme active in? What is the ph that they are most active? a. Enzyme organ ph b. 2. Using your knowledge of protein structure, explain in detail the effect of exposing an enzyme to a ph outside of its optimal range. 3. At what ph values is lipase likely to be denatured? 4. At what ph values is pepsin likely to be denatured? Model 2 Amylase Rate of Reaction Amylase is an enzyme that catalyzes the digestion of carbohydrates. The graphs in Model 2 pro- vide data on several factors that affect the function of amylase in the body. 5. What is the independent variable for each graph? A. B. C. 6. What is the optimum temperature for amylase? 7. A young child runs a fever of 40 C for 24 hours. Explain what effect this may have on his digestion. 8. Looking at graph B, describe the relationship between enzyme concentration and reaction rate. 9. Looking at graph C, what is the relationship between substrate concentration and the reaction rate? Why does the rate of reaction flatten out.
ATP The Free Energy Carrier How does the ATP molecule capture, store, and release energy? A sporting goods store might accept a $100 bill for the purchase of a bicycle, but the corner store will not take a $100 bill when you buy a package of gum. That is why people often carry smaller denominations in their wallets it makes everyday transactions easier. The same concept is true for the energy transactions in cells. Cells need energy (their currency ) to take care of everyday functions, and they need it in many denominations. As humans we eat food for energy, but food molecules provide too much energy for our cells to use all at once. For quick cellular transactions, your cells store energy in the small molecule of ATP. This is analogous to a $1 bill for your cells daily activities. Model 1 Adenosine Triphosphate (ATP) 1. The diagram of ATP in Model 1 has three parts. Use your knowledge of biomolecules or page 110 of the book to label the molecule with adenine, ribose sugar and a phosphate groups. 2. What is meant by the tri- in the name adenosine triphosphate? 3. On page 110, under How ATP stores energy, read and explain why ATP is referred to at a coiled spring? 4. What happens to ATP when it is hydrolyzed? 5. Model 2 illustrates a chemical reaction. Write the reaction as an equation, using the name or abbreviation of each of the two reactants and each of the three products.(pg 111 has example) + 6. What happens to the atoms from the water molecule during the hydrolysis of ATP? 7. Refer to figure 6.7 on page 111, which parts of reaction are exergonic, which parts are endergonic? 8. The reverse of this reaction is called phosphorylation. Why this name is appropriate for the reaction above? Video Questions: 1. What is the fuel we need for all our cells? 2. Label the major parts of the Mitochondria that the video points out as important. 3. Number the 3 stages of Cellular Respiration 4. Number how many ATPs result from each. 5. Which stage does CO 2 come from? 6. Which stage does O 2 go in? Anaerobic Respiration 7. During Lactic Acid Fermentation, how many ATP's can be made per glucose? 8. What is Alcohol made of? BIOFLIX 9. What does NAD (orange)pick up from the Carbon Molecule? 10. What are the blue balls? 11. What do they power the formation of as they move through the turbine?
ATP & CELLULAR RESPIRATION (Use the textbook and this worksheet to compl)ete the answers to the questions) Read This! It is estimated that more than 2 1026 molecules of ATP are hydrolyzed in the human body daily. If each molecule was used only once you would need approximately 160 kg (350 lbs) of ATP daily. The repeated use of ATP molecules through the ATP cycle saves the body a huge amount of resources and energy. ATP is synthesized in two ways: Substrate-level phosphorylation Energy released during a reaction, such as the breakdown of sugar molecules, is used directly to synthesize ATP. A small amount of energy is generated through this process. Electron transfer (oxidative phosphorylation) Energy from the movement of electrons from one molecule to another, via electron carriers, is used to synthesize ATP. Most cellular ATP is synthesized by electron transfer in the mitochondria. You will read about both ways in the cellular respiration chapter Glycolysis and the Krebs Cycle What reactions occur in the cell to turn glucose into carbon dioxide? Glucose is a high potential energy molecule. Carbon dioxide on the other hand is a very stable, low potential energy molecule. When a glucose molecule is converted to carbon dioxide and water during cellular respiration, energy is released and stored in high potential energy ATP molecules. The phases of cellular respiration that oxidize the glucose molecule to carbon dioxide are glycolysis, the pyruvate oxidation and the Krebs cycle. 1. What molecule from food is the primary reactant for glycolysis? (See book pg. 125-126 Fig 7.6-7.7) 2. How many carbon atoms are in that reactant molecule? (see pg. 38, Fig 3.6) 3. The carbon atoms from glucose end up in pyruvate molecules as a product of glycolysis. How many carbon atoms are in a pyruvate molecule? 4. How many pyruvate molecules are made from each glucose molecule? 5. What input of energy is required in glycolysis? 6. Referring to PGAL (also called G3P) in Fig 7.7 in book), propose an explanation for why the author of this activity put PGAL at the highest point in the Model 1 diagram. 7. What is the net production of ATP by glycolysis? 8. What is the 'electron shuttle in fig 7.3 pg 121 that acts as an electron acceptor in glycolysis? How does it work? 9. Looking at Model 1, what is the source of the four phosphates (Pi) that are added to the ADP molecules to make the four ATP molecules? Model 2- Pyruvate Oxidation According to Model 2 & Ch 7.4 pg. 128 10. Where in a cell does pyruvate oxidation take place? 11. During the pyruvate oxidation, the pyruvic acid molecule is decarboxylated. What molecule is removed during this process? 12. When coenzyme A bonds to the decarboxylated pyruvic acid what molecule is produced? 13. Has any ATP been used or produced during pyruvate oxidation? 14. How many acetyl-coa, carbon dioxide, and NADH molecules are produced in pyruvate oxidation for each glucose molecule that undergoes cellular respiration?
(See book pg. 128-130 Fig 7.11-7.12) 15. Where in the cell does the Krebs cycle take place? 16. What molecule is introduced to the Krebs cycle from pyruvate oxidation? 17. Is oxygen needed as a reactant in the Krebs cycle (is it in the diagram? 18. How many carbon atoms are in oxaloacetate? 19. How many carbon atoms are in citrate? 20. Where did the extra carbon atoms come from to convert oxaloacetate into citrate? 21. How many carbon atoms are in α-ketoglutarate? 22. Where did the missing carbon atom go during the conversion of citrate to α-ketoglutarate? 23. How many carbon atoms are in succinate? 24. Where did the missing carbon atom go during the conversion of α-ketoglutarate to succinate? 25. How many turns of the Krebs cycle occur for every glucose molecule (C6H12O6) that undergoes cellular respiration? 26. How many of each of the molecules below are produced in the Krebs cycle of every glucose mol- ecule that undergoes cellular respiration? CO2 ATP NADH FADH2 When the body runs out of readily available carbohydrate (glucose) molecules, it will turn to stored glycogen, then fats, and finally proteins as an energy source. The pathways to the right illustrate how these molecules are prepared to enter the cellular respiration pathway. 27. For each of the products above (excluding urea) identify the phase of cellular respiration where the molecules would enter the cellular respiration process. a. PGAL b. acetyl-coa c. pyruvate 28. Glucose has six carbons. A fat molecule could have ten times that many carbons. Predict how the number of ATP molecules produced would differ between a glucose molecule and a fat molecule.
The Electron Transport Chain & Chemiosmosis(Oxidative Phosphorylation) How are the electrons in NADH and FADH2 used to make ATP during cellular respiration? The final phase of cellular respiration is oxidative phosphorylation. Both the electron transport chain and chemiosmosis make up oxidative phosphorylation. During this phase of cellular respiration, all of the NADH and FADH2 that were produced in other phases of cellular respiration (glycolysis, pyruvate oxidation, and Krebs cycle) are used to make ATP. The process occurs in the protein complexes embedded in the inner mitochondrial membrane. (See book pg. 132-133 Fig 7.13-7.14) 29.Name the region in Model 1 where the highest concentration of hydrogen ion (H+) is located. (fig 7.13) 30. How do the hydrogen ions reach this area? 31. High potential energy electrons provide the energy necessary to pump hydrogen ions across the inner mitochondrial membrane. a. What molecules carry these high potential energy electrons? b. Where (what previous reactions) did these electron acceptor molecules come from? d. Is the release of an electron from one of these electron acceptor molecules oxidation or reduction? c. As the electrons are released from the electron acceptor molecules, what do they convert back to? 32. Because of its role in aerobic respiration, oxygen is essential for most living things on Earth. What is the role of molecular oxygen (O2) in the electron transport chain? (arrow pointing to it) 33. What compound is formed as a final product of the electron transport chain? (it has dashed circle around it) 34. Is any ATP produced or used in Model 1 of the electron transport chain? 35. Describe the movement of hydrogen ions through the membrane illustrated in Model 2 (fig 7.15). (See book pg.133 Fig 7.15) 36. What is the name of the embedded protein that provides a channel for the hydrogen ions to pass through the membrane? 37. The flow of hydrogen ions through the protein channel provides free energy to do work. What process (circled) in Model 2 requires energy? READ THIS! Research has shown that a protein rotor down the middle of the ATP synthase complex turns as hydrogen ions flow through. This rotates other proteins, which then squeeze the ADP and inorganic phosphate groups together to form ATP. 38. (see pg. 134 Fig 7.16) Considering all the stages of cellular respiration (glycolysis, pyruvate oxidation, Krebs cycle, and oxidative phosphorylation) how many ATP molecules are produced from one glucose molecule, assuming ideal circumstances?