Unit 2B Review 2024 Biochemistry Answer Key PDF

Name ___________________________________ Block_______ Review for Chapter 2: Biochemistry Answer Key 1. Interpret the general chemical equation, A + B 🡪 AB, in words. The reactants A and B react and combine to form the product AB 2. Using th...

Name ___________________________________ Block_______ Review for Chapter 2: Biochemistry Answer Key 1. Interpret the general chemical equation, A + B 🡪 AB, in words. The reactants A and B react and combine to form the product AB 2. Using the equation above, which are the reactants and which are the products? Reactants = A and B, products = AB 3. Given the molecular formula for chocolate (theobromine) C7H8N4O2, which atoms and how many of each are present in the molecule? 7 Carbons, 8 Hydrogens, 4 Nitrogens, 2 Oxygens 4. On the graph, what is represented by the letters? A- reactants B- products C- activation energy 5. What is activation energy, and how do enzymes affect it? Energy needed to get the reaction started. Enzymes lower the activation energy. Progress of Reaction 6. Identify each of the graphs to the right as exergonic or endergonic. EXPLAIN how you know. Graph I – endergonic (energy went in- products have more energy than reactants) Graph II - exergonic (energy went out- products have less energy than reactants) 7. On graph II, what is the difference between reactions B and C and what is responsible for this difference? Enzyme- C has an enzyme which has lowered the activation energy 8. What is an enzyme? An Enzyme is a protein that speeds up chemical reactions by lowering the activation energy needed 9. On the figure label the following: substrate, product, enzyme, and active site. 10. Explain what is happening in the figure above. Include 3 steps. a- Substrate fits into active site of enzyme b- Reaction occurs c- Products are released, the enzyme is unchanged and can be used again. 11. Refer to the figure above. What happens to the enzyme after the reaction is complete? Nothing happens, enzyme is unchanged and can be used again.  12. What is the function of an enzyme? What conditions can affect how well an enzyme functions? Speed up chemical reactions by lowering the activation energy of the reaction. pH and temperature affect how well an enzyme can work. 13. Why are enzymes often explained using an analogy of a lock-and-key? (Give 4 reasons why this analogy works). a. reusable b. work with a specific substrate with complex shape c. cause change d. if shape is changed, does not work 14. When working in the laboratory, you discover that the solutions you are working with are tomato juice with a pH of 4 and soap with a pH of 10. By comparing the pH of these substances with that of pure water, would you find that these substances are acidic or basic? Explain. Tomato is acid, below 7. Soap is basic, above 7 15. According to the graph to the right, which enzyme would you expect to find in a bacterium growing in a hot spring? And WHY? Y- optimal temperatures are very warm (90*C) 16. According to the figure, which enzyme has an optimal temperature of 40oC? EXPLAIN. X- highest activity for the enzyme is at 40*C 17. In the figure, why does enzyme X not function at 70ºC? Enzyme denatures- lost shape and no longer can function. 18. What happens to the activity of an enzyme if its pH or temperature is changed from “optimal conditions”? And WHY? Activity is lowered, as move away from the optimal condition, enzyme denatures. As the shape changes the enzyme becomes less effective. 19. Identify a possible independent variable(s) (x-axis) that could be paired with each graph below. Explain how the chosen variable affects the rate of reaction. Temp or pH - there is an optimal Time, Enzyme or Substrate Concentration Increases to a maximum 20. How does a change from ATP to ADP provide an organism with energy? Energy is released when bonds are broken. 21. On the ATP diagram to the right, circle the bond that contains the most energy (Hint: It is broken to release energy when ATP is used!)  22. Compare and Contrast Photosynthesis and Cellular Respiration in the table below: Photosynthesis Cellular Respiration Make food for plants- store sun’s energy Release energy from food Function/Purpose Chloroplast Mitochondria Location/Organelle H2O & CO2 & light C6H12O6 & O2 Reactants C6H12O6 & O2 H2O & CO2 & ATP (energy) Products H2O + CO2 + ---light🡪 C6H12O6 + O2 C6H12O6 + O2 🡪 H2O + CO2 + ATP Equation Autotrophs ALL LIVING THINGS! Organisms 1. Light Dependent Reactions 1. Glycolysis Stages/Parts of the 2. Calvin Cycle (Light Independent Reaction) 2. Krebs Cycle Reactions 3. Electron Transport Chain (ETC) 23. Label the diagram below and explain what is happening. 1-light dependent reactions, 2-thylakoid, 3-calvin cycle, 4-stroma, 5-light, 6-water, 7-oxygen, 8-NADPH, 9-ATP, 10- carbon dioxide, 11-glucose/sugar, 12-NADP+, 13-ADP+P 24. Briefly explain the purpose of stages (1) and (3) 1= Light Dependent Reactions- purpose is to capture light energy as molecules (NADPH & ATP) 3= Calvin Cycle - purpose is to make sugars using energy from Light Reactions, the H from the water and CO2 25. What organelle is this process occurring in? chloroplast 26. Label the diagram below. 27. Briefly explain the purpose of stages 1, 2, and 3. How many ATPs are made during each process? 1= glycolysis - starts to break down glucose, releases 2 ATP (and NADH) 2= Krebs Cycle, finishes breaking down glucose into CO2, releases 2 ATP (and NADH) 3= Electron Transport Chain, converts NADH into ATPs, make ~32 ATP 28. In which organelle are the above processes happening? mitochondria 29. Why do autotrophs carry out both photosynthesis and cellular respiration? Needs to do PS to make food (store sun’s energy as sugars). Need to do CR to break down food into usable energy. 30.