STATEUNIVERSITYCOLLEGE AT BUFFALO

Department of Biology

Biology 100Spring 2004

Principles of BiologyDr.Wadsworth

Mid-Term Exam 2a

Enzymes, Photosynthesis, and Cellular Respiration

Cover Sheet

Name: ______

(Print)

Instructions.

1.Print your name in the space designated on this cover sheet.

2.Be sure that your exam has 9 pages including this cover sheet.

3.Read each question carefully and answer in the space provide

4.At the end of the exam there are 6 short answer questions. Answer only 5 of these 6 questions. Answering all six questions may reduce your grade. Under the question you choose not to answer, please write the word "Skip". Failure to write "SKIP" under the one question you choose not to answer will reduce your grade.

Multiple Choice

Choose the best answer for the question or the best ending for each statement. Write the letter (A-E) which corresponds to the best answer on the line before the question. (2 pts each)

_____ 1. Which of the following best illustrates the first law of thermodynamics, the law of conservation of energy?

  1. Anabolic reactions always release free energy.
  2. The chemical energy of ATP can be converted to mechanical energy by our muscles.
  3. The high energy electron carrier NAD receives electrons from glucose and delivers the electrons to oxygen.
  4. Endogonic reactions are spontaneous
  5. Exergonic reactions are spontaneous

_____ 2. A Kilocalorie is a unit of energy. Nutritionists also use this term to describe the energy in food. One nutritional Calorie, like those described on the back of a bag of potato chips, is the equivalent to a kilocalorie. (One nutritional Calorie = 1 kilocalorie.) A single potato chip has 20 nutritional Calories. If the energy in the potato chip were used to heat a liter of water, how much would the temperature of the water rise.

  1. Two tenths of a degree Celsius.
  2. Two degrees Celsius
  3. Twenty degrees Celsius.
  4. Two hundred degrees Celsius.
  5. Two thousand degrees Celsius

_____ 3. Which of the following best describes a spontaneous reaction?

  1. Spontaneous reactions are associated with anabolism
  2. All spontaneous reactions are catalyzed by enzymes
  3. Spontaneous reactions release free energy
  4. Spontaneous reactions do not need enzymes to occur
  5. Spontaneous reactions almost never occur in cells.

_____ 4. The hydrolysis of ATP is one of the main energy releasing reactions in the cell. Specifically to what does "hydrolysis of ATP" refer?

  1. The catabolism of DNA to nucleotides
  2. The catabolism of ATP to ribose, phosphate and its nitrogenous base
  3. The anabolism of ATP to form ribose, phosphate and its nitrogenous base
  4. The breaking of any chemical bond in ATP
  5. The removal of a phosphate from ATP to form ADP

_____ 5. In an oxidation/reduction reaction the molecule that is oxidized:

  1. loses energy
  2. loses electrons
  3. gains energy
  4. forms hydrogen bonds with oxygen
  5. forms covalent bonds with oxygen

_____ 6. Which of the following would be the best definition of an enzyme?

  1. A protein that adds energy to endogonic reactions to make them spontaneous.
  2. A protein that increases the rate of exergonic reactions
  3. A protein that converts endogonic reactions to spontaneous reactions
  4. A protein that adds activation energy to endogonic reactions
  5. A protein that converts products to substrates

_____ 7. The “Lock and Key Model” is used to describe which of the following characteristics of enzymes?

  1. Allosteric changes can inactivate enzymes
  2. Substrate Specificity
  3. Enzymes can couple endogonic and exergonic reactions
  4. Enzymes are required for active transport across membranes
  5. Enzymes are proteins made of strings of amino acids

_____ 8. Which of the following best describes the relationship between the ATP/ADP cycle and metabolism?

  1. Metabolism functions by producing ATP
  2. The ATP/ADP cycle involves oxidation and reduction
  3. ATP creates the energy needed for metabolism
  4. ATP is found in animals and ADP is found in plants
  5. Catabolism produces ATP, Anabolism uses ATP

_____ 9. The enzyme sucrase breaks down table sugar (a disaccharide) to form two monosaccharides molecules. This is an example of a:

  1. Endothermic reaction
  2. Feedback Inhibition
  3. Catabolic reaction
  4. Enzyme regulation
  5. Substrate inhibition

_____ 10. An ordered sequence of chemical reactions with specific enzymes acting at each step is the definition of:

  1. High energy electron carrier
  2. Lock and Key Model
  3. Metabolic Pathway
  4. Activation Energy
  5. Intermediary Compounds

_____11. Which of the following is not associated with the reduction of activation energy by enzymes?

  1. Realigning of electrons in covalent bonds
  2. Removing activation energy with NADH
  3. Stressing of chemical bonds
  4. Orienting of substrates to promote the chemical reaction

_____ 12. Lactobacteria are the bacteria that turn milk into yogurt by converting the sugar in milk into lactic acid. The lactic acid thickens and flavors the milk thus making yogurt. From the perspective of the bacteria, what is the benefit of this fermentation process?

  1. It provides lactic acid which is necessary for reproduction in bacteria
  2. The lactic acid in the milk is the storage form of energy in bacteria
  3. This process gets rid of the sugar which is poisonous to bacteria
  4. It produces NADPH which is essential to light independent reaction in a dark refrigerator.
  5. It allows the bacteria to make ATP from milk sugar in the absence of oxygen.

_____ 13. When the cell has high levels of ATP, the ATP binds to an early enzyme of glycolysis, PFK (phosphofructokinase). The binding of ATP to PFK inactivates the enzyme. This is an example of which of the following?

  1. Oxidation/Reduction
  2. Fermentation
  3. Feedback Inhibition
  4. Spontaneous Reactions
  5. ATP/ADP Cycle

_____ 14. Where does glycolysis occur in a plant cell?

  1. The central vacuole
  2. The chloroplasts
  3. The cytosol
  4. The inner mitochondrial membrane
  5. The matrix

_____ 15. During cellular respiration, glucose is broken down to carbon dioxide and 38 ATP are generated from 38 ADP. What is the benefit of this process to cells.

  1. It provides ATP for cellular work
  2. It breaks down the glucose in food
  3. It gets rid of excess ADP
  4. It produces oxygen which is essential to life
  5. It links glycolysis with oxidative phosphorylation

_____16. During fermentation, electrons are removed from NADH so that glycolysis can continue. Which of the following molecules eventually accepts the electrons from NADH?

  1. Pyruvate
  2. ATP
  3. NAD
  4. Glucose
  5. ADP

_____ 17. During cellular respiration, which of the following processes produce the greatest number of ATP?

  1. oxidative phosphorylation
  2. Krebs Cycle
  3. Calvin Cycle
  4. Light Independnet Reaction
  5. Glycolysis

_____ 18. What is the direct source of energy used by the ATPase for the synthesis of ATP during chemiosmosis in the mitochondria?

  1. High energy electrons of NADPH
  2. High energy electrons of NADH
  3. The movement of protons into the matrix
  4. The breakdown of glucose to form carbon dioxide
  5. The hydrolysis of ATP to form ADP and phosphate

_____ 19. Which of the following are substrates for fermentation?

  1. pyruvate and lactate
  2. lactate and ethanol
  3. lactate and ATP
  4. pyruvate and ATP
  5. pyruvate and NADH

_____ 20. What is the important difference between a chemotroph and a phototroph.

  1. Where they get their carbon to make organic molecules
  2. How they break down glucose to make ATP
  3. Whether they require oxygen or not
  4. Where they get their energy to fix carbon dioxide
  5. What their end product of glucose catabolism is.

_____21. During the light reaction, protons are pump into the thylakoid lumen. What is the eventual fate of these protons?

  1. They move back into the stroma through the ATPase complex
  2. They are excreted by the cell as a waste product
  3. They generate heat by combining with oxygen to form water
  4. They generate ATP by combining with oxygen to form water
  5. They combine with carbon dioxide to make glucose in the calvin cycle

_____ 22. A high school student investigated the growth of bean plants in different colors of light. He found that after a month of growth, plants in blue light grew better than plants in green light. What is the best explanation for this difference?

  1. Blue light has more energy than green light.
  2. Blue light but not green light is absorbed by chlorophyll
  3. Green light can only be used for the light reaction, while blue light can power both the light and the light independent reaction.
  4. Blue light is involved with fluorescence while green light is involved with resonance.
  5. Amateurs shouldn’t grow bean plants

_____ 23. Which of the following is most important for transferring energy from the light reaction of photosynthesis to the light independent reaction of photosynthesis?

  1. NADH
  2. ATP
  3. Glucose
  4. Carbon dioxide
  5. Oxygen

_____ 24. Rubisco functions during photosynthesis by:

  1. Absorbing blue photons
  2. Catalyzing photolysis
  3. Synthesizing glucose
  4. Utilizing ATP and NADPH
  5. Fixing Carbon Dioxide

_____ 25. Electrons move through the electron transport chain during the light reaction of photosynthesis. Which of the following best describes where the electrons finally end-up in the Z-scheme of the light reaction of photosynthesis?

  1. Glucose
  2. Water
  3. Oxygen
  4. ATP
  5. NADP

Short Answer Questions

Answer only five of the following six questions. Under the question you choose not to answer, write the work "SKIP". (10 pts each)

26. Photosynthesis cycles NADP/NADPH. Explain how this cycling of NADP and NADPH function during photosynthesis.

27. In most plants the light independent reaction is active only when the light reaction is active. Explain how the regulation of rubisco contributes the light independent reaction being off in the dark and on in the light.

28. Describe chemiosmosis and explain how it contributes to ATP production during respiration?

29. An aerobic cell can produce 38 ATP from one glucose molecule. List the metabolic processes that produce these ATP and list how many ATP are produced by each process.

30. How do the antenna pigments of the photosystem function to contribute energy to the reaction center?

31. Explain how an inhibitor inactivates an enzyme?