1 Cellular Energy 1. Photosynthesis is carried out by which of the following? A. plants, but not animals B. animals, but not plants C. bacteria, but neither animals nor plants D. all living organisms 2. Examine the picture of the chloroplast below. Chloroplasts contain flattened disks known as thylakoids that are stacked into grana. In the thylakoids are proteins that A. help capture oxygen from the atmosphere during the process of cellular respiration. B. help capture light from the Sun during the process of cellular respiration. C. help capture oxygen from the atomosphere during the process of photosythesis. D. help capture light from the Sun during the process of photosynthesis.
2 3. During the process of photosynthesis, plants use energy from the Sun to convert carbon dioxide and water into glucose and oxygen. These products are, in turn, used by the plant or animals that eat the plant during cellular respiration to produce ATP. ATP molecules store cellular energy. When phosphate groups are removed and molecules of ADP are formed, energy is released. This energy can be used to perform A. osmosis. B. electron transport. C. diffusion. D. cellular work. 4. Technology Enhanced Questions are not available in Word format. 5. Cells obtain energy by either capturing light energy through photosynthesis or by breaking down carbohydrates through cellular respiration. In both photosynthesis and cellular respiration, the energy is ultimately derived from the Sun in a one-way process. A. highly efficient process which involves no loss of heat to the environment. B. reversible process. C. pathway that involves taking in heat from the environment at each step. D. 6. During photosynthesis, plant cells take in water (H 2 O) and carbon dioxide (CO 2 ) and release oxygen (O 2 ). How is this different from what takes place during aerobic respiration? A. During aerobic respiration, the mitochondria form CO 2 during the process of fermentation. B. During aerobic respiration, cells take in O 2 and release CO 2, H 2 O, and ATP. C. During aerobic respiration, cells use ATP to convert insulin into glucose and CO 2. D. During aerobic respiration, O 2 is inhaled and CO 2 and H 2 O are exhaled. 7. Organisms undergo many different processes in order to be able to store energy and utilize that energy. Through which of the following processes is energy released in the form of ATP? A. photosynthesis B. phototropism C. cellular respiration
3 D. respiration 8. During photosynthesis, plants capture light energy from the Sun to break weak bonds in reactants, such as carbon dioxide and water, and form carbon-containing molecules, such as glucose. The carbon-containing molecules can then be used A. to synthesize essential amino acids. B. to produce inorganic compounds, such as sulfuric acid. C. to assemble larger molecules, such as DNA, proteins, and fats. D. all of these 9. In order to function properly, cells must perform many reactions. Metabolism is the sum of all the chemical reactions in an organism. During metabolism, ATP A. I, II, and III B. I and II only C. III only D. I and III only I. is broken down to fuel chemical reactions. II. is created by chemical reactions. III. is shuttled from one cell to another. 10. Technology Enhanced Questions are not available in Word format.
4 11. Through the process of hydrolysis, cells remove phosphate groups from molecules of ATP to form molecules of ADP. This hydrolytic reaction results in A. the breaking of low-energy bonds to produce free energy. B. the breaking of high-energy bonds to produce free energy. C. the formation of low-energy bonds to store free energy. D. the formation of high-energy bonds to store free energy. 12. A plant cell is shown below. Cellular respiration occurs in the. A. vacuole B. chloroplast C. mitochondrion D. cell wall 13. Which of a cell's organelles releases energy stored in food? A. lysosomes B. mitochondria C. endoplasmic reticulum D. chloroplasts 14. Technology Enhanced Questions are not available in Word format. 15. During photosynthesis, radiant energy from the Sun is transferred to plants and other photosynthetic organisms. The chloroplasts in the cells of these organisms then transform the radiant energy into chemical potential energy stored in the bonds of
5 protein molecules. A. water molecules which then evaporate through openings called stomata. B. carbon dioxide. C. highly condensed carbon compounds, such as carbohydrates. D. 16. How do cells get energy to perform their necessary functions? A. Cells get energy by taking in nutrients from food. B. Cells get energy by moving water from one organelle to another. C. Cells get energy by dissolving waste products of the body. D. Cells get energy only by taking in oxygen from the atmosphere.
6 17. In the respiration-photosynthesis cycle shown above, what are the products of photosynthesis that belong in box 1? A. glucose and oxygen B. protein and nucleic acids C. carbon dioxide and water D. ATP and methane 18. During cellular respiration, energy is stored in the form of. A. water B. oxygen C. ATP D. food 19. Which of the following are reactants in the process of cellular respiration? A. carbon dioxide and oxygen B. glucose and oxygen C. glucose and water D. carbon dioxide and water 20. Which type of macromolecule contains high-energy bonds and is used for long-term energy storage? A. sugars B. lipids C. enzymes D. proteins
7 21. What is the function of stomata in plants? A. to allow gas exchange between the environment and the inside of leaves B. to absorb light energy from the Sun C. to transport materials from the leaves to the soil D. to transport materials from the soil to the leaves 22. In which organelle does photosynthesis take place? A. chloroplast B. mitochondrion C. nucleus D. endoplasmic reticulum 23. During cellular respiration, the bonds of food molecules are broken, so energy can be released to fuel other cellular processes. In order for this to occur, which of the following statements must be true? A. B. New compounds with lower-energy bonds must be formed when the high-energy bonds in food molecules are broken. New compounds with higher-energy bonds must be formed when the low-energy bonds in food molecules are broken. The new compounds formed must be more complex than the food molecules that were broken down. C. D. The energy in the new compounds that are formed must be equal to the energy in the bonds of the food molecules. 24. The above illustration shows the molecule used by some cells to temporarily store energy. The molecule is used in almost all energy-requiring reactions in cells. This molecule could be considered the "gas" that powers a cell's "engine." What is the name of this molecule? A. adenosine triphosphate B. ethyl alcohol
8 C. adenosine diphosphate D. glucose 25. A chloroplast is a type of plastid that is involved in the transformation of energy within a cell because this is the organelle in which A. cellular respiration occurs. B. genetic material is stored. C. starches are stored. D. photosynthesis occurs. 26. Which of the following organelles convert solar energy into glucose and oxygen? A. mitochondria B. endoplasmic reticuli C. vacuoles D. chloroplasts
9 27. Technology Enhanced Questions are not available in Word format. 28. Which organelle in the plant cell shown above makes glucose from sunlight? A. chloroplast B. mitochondrion C. vacuole D. cell wall 29. Adenosine triphosphate, or ATP, is primarily used as in living organisms. A. a reproductive enzyme B. a source of energy C. a muscle relaxing hormone D. a blood coagulant
10 30. Which of the following is true about plants and cellular energy? A. B. C. D. Plants use light energy to produce food molecules during photosynthesis, and obtain cellular energy from the bonds of these food molecules during cellular respiration. Plants use light energy to produce food molecules during cellular respiration, and obtain cellular energy from the bonds of these food molecules during photosynthesis. Plants can both use light energy to produce food molecules and obtain cellular energy from the bonds of these food molecules during photosynthesis. Plants can both use light energy to produce food molecules and obtain cellular energy from the bonds of these food molecules during cellular respiration. Answers 1. A 2. D 3. D A 6. B 7. C 8. C 9. B B 12. C 13. B D 16. A 17. A 18. C 19. B 20. B 21. A 22. A 23. A 24. A 25. D 26. D A 29. B 30. A Explanations 1. Photoautotrophs are organisms that can perform photosynthesis, a pathway that converts the energy from sunlight into the chemical energy of organic molecules. These molecules can then store the collected energy for later use when needed. Land plants, algae, and some kinds of bacteria are photoautotrophs, but animals cannot use light energy. They require an input of energy that is already in an organic molecule form (i.e. food).
11 2. Chloroplasts are mainly found in plants. In the chloroplasts are stacks of flattened disks that contain proteins that help capture light from the Sun during the process of photosynthesis. 3. When a phosphate group is removed from a molecule of ATP, a molecule of ADP is formed. Energy is released, so it can be used to perform cellular work, such as obtaining, transforming, or transporting materials and eliminating wastes There is a one-way flow of energy from the Sun to all of the organisms in an ecosystem. Energy flows first into the lowest trophic level of an ecosystem via photosynthesis. Carbohydrate products from photosynthesis are then broken down to liberate energy through cellular respiration. Heat is lost to the environment at each step during energy transfer through the ecosystem. 6. During aerobic respiration, glucose is broken down in a cell's mitochondria. The products that result from the breakdown of glucose include carbon dioxide, water, and energy. C 6 H 12 O 6 (glucose) + 6 O 2 (oxygen) 6 CO 2 (carbon dioxide) + 6 H 2 O (water) + ATP (energy) Therefore, aerobic respiration is different from photosynthesis because during aerobic respiration, cells take in O 2 and release CO 2, H 2 O, and ATP. 7. Energy in the form of ATP is then released during cellular respiration. The process of cellular respiration can be generally expressed by: glucose + oxygen carbon dioxide + water + ATP The cycling of energy and mass through the processes of photosynthesis and respiration show how the mass and energy of the reactants in a biochemical process can be transferred into the products. However, according to the laws of conservation of mass and energy, the total amount both remains the same. 8. The cellular processes of photosynthesis and respiration involve the transformation of matter and energy. Carbon-containing molecules, such as glucose, that are formed as a product of photosynthesis can be used to assemble larger molecules, such as DNA, proteins, and fats. Furthermore, energy that is released when these molecules react with oxygen during cellular respiration can be used to fuel other life processes. 9. During metabolism, ATP is broken down to fuel chemical reactions, or it can be created by chemical reactions. Metabolism is often divided into two main categories - catabolism and anabolism. Catabolism is the set of chemical reactions that breaks large molecules into smaller units. During catabolic processes, ATP (energy) is created and released. Anabolism is the set of chemical reactions that builds large molecules from smaller units. During anabolic processes, ATP (energy) is broken down and used for fuel. ATP usually remains in the cell that creates it, so it is not shuttled from cell to cell Adenosine triphosphate, or ATP, is a macromolecule used by the body for energy storage. ATP contains adenine, ribose, and three phosphate groups. Each of the phosphate bonds stores a large quantity of energy
12 which is released for use when the bond is broken. When this reaction occurs in reverse, cells perform dehydration reactions to add phosphate groups to ADP and store energy for later use. 12. Only plants and other photosynthetic organisms, such as phytoplankton, can make sugar molecules using energy from the Sun. However, plant cells and animals cells use the energy stored in the bonds of the sugar molecules to fuel cellular processes. The process in which energy is released from glucose molecules and used to do cellular work is called cellular respiration. In either plant or animal cells, cellular respiration takes place primarily in the mitochondria. 13. Mitochondria are often referred to as the main power source of a cell. That is because of mitochondria's ability to break down glucose and other food molecules to produce energy. The energy released by mitochondria is stored in an ATP molecule. Without mitochondria, cells would not be able to generate energy to perform cellular work, and cellular death would be the result Chloroplasts in photosynthetic organisms convert radiant energy from the Sun into condensed carbon compounds such as carbohydrates. The plants then either convert these carbohydrates into structural or storage materials, or use them to generate ATP for cellular processes. 16. Cells get energy to perform their necessary functions by taking in nutrients from food. During the digestive process, nutrients from food are broken down and used to synthesize sugar, or glucose, molecules. When the glucose is broken down, a lot of energy is created. This energy is then used for various cell functions. 17. The processes of photosynthesis and cellular respiration are interdependent. The products of one process act as the starting materials, or reactants, of the other process. Photosynthesis produces glucose and oxygen. These products are used as reactants in the process of aerobic respiration. Aerobic respiration produces carbon dioxide and water. These products are used as reactants in the process of photosynthesis. 18. During aerobic respiration, cells use oxygen to release the energy stored in glucose. This energy is temporarily stored in the form of ATP (adenosine triphosphate), and water and carbon dioxide are released as wastes. 19. The process of cellular respiration can be generally expressed by: glucose + oxygen carbon dioxide + water + ATP So, the reactants in cellular respiration are glucose and oxygen. 20. Lipids are macromolecules used by the body for long-term energy storage. Lipids, like sugars, are composed primarily of carbon, hydrogen, and oxygen. They contain high-energy bonds that can be broken by cells to release energy to do cell work. Sugars contain high-energy bonds, but are used by the body for short-term energy storage.
13 21. On the underside of leaves, pairs of guard cells create microscopic pores called stomata. These allow for the exchange of gases between the environment and the interior cells. This gas exchange is vital to plant cell photosynthesis, which requires carbon dioxide gas as a reactant. In addition, excess oxygen created as a product is removed through stomata. 22. Photosynthetic pigments, which absorb and convert light energy into chemical energy, are embedded in the membranous structure of chloroplasts in plant cells. These pigments give chloroplasts, and plants, their characteristic green color because they absorb all colors of the visible spectrum except green. Once light energy is converted into a chemical form, enzymes present inside chloroplasts can use this energy to synthesize fuel storage molecules like glucose and starch. 23. The cellular processes of photosynthesis and respiration involve the transformation of matter and energy. According to the law of conservation of energy, energy can neither be created nor destroyed. So, in order to obtain excess energy to fuel cellular processes, the bonds formed in the new compounds must have less energy than the bonds in the original food molecules. 24. When adenosine binds with two phosphate molecules, it is known as adenosine diphosphate (di meaning 2). With three phosphate molecules, it is adenosine triphosphate (tri meaning 3). Cells use ATP (Adenosine TriPhosphate) to temporarily store energy. When the cell is in need of energy, a reaction occurs in which the ATP becomes ADP (Adenosine DiPhosphate) and energy is released. 25. Plastids are membrane-bound organelles that can be found in plant and algae cells. In plants, these organelles can differentiate into various forms to play different roles within the cell. A chloroplast is a type of plastid that is involved in the transformation of energy within a cell because this is the organelle in which photosynthesis occurs. Other plastids perform different functions. For example, amyloplasts are used to store starch; chromoplasts are used for pigment synthesis and storage; and elaioplasts store fats within the cell. 26. In chloroplasts, organelles only found in autotrophs, such as plants, algae, and cyanobacteria, carbon dioxide and water are transformed into glucose and oxygen when solar energy excites electrons in chlorophyll Chloroplasts are organelles used by plant cells to make a sugar called glucose from sunlight. Energy stored in the chemical bonds of the sugar molecules can be used, either by the plants or by the animals that eat them, to fuel body processes. Because plants make their own food, they make up the first (and most important) trophic level in the energy pyramids of terrestrial ecosystems. Some microorganisms, called phytoplankton, also have chloroplasts. These organisms form the first trophic level in marine ecosystems. 29. ATP is a high-energy molecule composed of a purine base (adenine), a five-carbon sugar (ribose), and three phosphate groups. It is primarily used as a source of energy in living organisms. ATP supplies energy to every endergonic reaction that occurs in the body. For example, the energy from ATP can be used by the organism to obtain, transform, and transport materials, and to eliminate wastes. 30. Photosynthesis is the process by which organisms, such as green plants, use light energy to produce food. Cellular respiration is the process by which living things, including both plants and animals, obtain energy from the bonds of food molecules. Therefore, plants use light energy to produce food molecules during photosynthesis, and obtain cellular energy from the bonds of these food molecules during cellular respiration.