Bio 1 - Unit 5 Test: Cellular Energy

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Bio 1 - Unit 5 Test: Cellular Energy - Quiz

Questions and Answers
  • 1. 

    The three-carbon molecule formed by glycolysis is ___.

    • A.

      Pyruvate

    • B.

      NADH

    • C.

      Citric acid

    • D.

      Carbon dioxide

    Correct Answer
    A. Pyruvate
    Explanation
    Glycolysis is the process that breaks down glucose into pyruvate. Pyruvate is a three-carbon molecule that is formed as a result of glycolysis. It is the end product of this metabolic pathway and serves as a precursor for various other metabolic reactions in the cell. Therefore, the correct answer for the three-carbon molecule formed by glycolysis is pyruvate.

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  • 2. 

    In the diagram to the right, what is structure A?

    • A.

      Folded inner membrane

    • B.

      Mitochondrial matrix

    • C.

      Stroma

    • D.

      Thylakoid membrane

    Correct Answer
    A. Folded inner membrane
    Explanation
    The correct answer is folded inner membrane. This is because the diagram shows a structure that is located inside a larger membrane, suggesting that it is an inner membrane. Additionally, the structure appears to be folded, which is a characteristic of the inner membrane of mitochondria.

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  • 3. 

    In the diagram to the right, what is structure B?

    • A.

      Folded inner membrane

    • B.

      Mitochondrial matrix

    • C.

      Stroma

    • D.

      Thylakoid membrane

    Correct Answer
    B. Mitochondrial matrix
    Explanation
    Structure B in the diagram refers to the mitochondrial matrix. The mitochondrial matrix is the innermost compartment of the mitochondrion, surrounded by the folded inner membrane. It contains a gel-like substance that contains enzymes responsible for various metabolic reactions, including the citric acid cycle. The matrix is where most of the ATP production occurs through oxidative phosphorylation. Therefore, the correct answer is mitochondrial matrix.

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  • 4. 

    Which of the following stages occurs in the mitochondrial matrix?

    • A.

      Krebs cycle

    • B.

      The Calvin cycle

    • C.

      Glycolysis

    • D.

      Oxidative phosphorylation

    Correct Answer
    A. Krebs cycle
    Explanation
    The Krebs cycle, also known as the citric acid cycle, occurs in the mitochondrial matrix. It is a series of chemical reactions that takes place in the presence of oxygen and plays a crucial role in the aerobic respiration process. During the Krebs cycle, acetyl-CoA is broken down, producing carbon dioxide, ATP, NADH, and FADH2, which are important energy carriers. This cycle is an essential step in the overall process of cellular respiration, converting stored energy in glucose into usable ATP molecules.

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  • 5. 

    Which organelle converts molecules from the food you eat into usable energy?

    • A.

      Golgi apparatus

    • B.

      Chloroplast

    • C.

      Mitochondrion

    • D.

      Lysosome

    Correct Answer
    C. Mitochondrion
    Explanation
    The mitochondrion is the correct answer because it is the organelle responsible for converting molecules from the food we eat into usable energy. This organelle is often referred to as the "powerhouse" of the cell, as it produces adenosine triphosphate (ATP), which is the main source of energy for cellular processes. The mitochondrion carries out cellular respiration, a process that breaks down glucose and other molecules to generate ATP.

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  • 6. 

    What is another name for the Krebs cycle?

    • A.

      Citric acid cycle

    • B.

      Calvin cycle

    • C.

      Motor cycle

    • D.

      Cell cycle

    Correct Answer
    A. Citric acid cycle
    Explanation
    The Krebs cycle is also known as the citric acid cycle. It is a series of chemical reactions that occur in the mitochondria of cells, where acetyl-CoA is oxidized and carbon dioxide is released. The cycle produces energy-rich molecules such as ATP and NADH, which are used in cellular respiration. The Calvin cycle, on the other hand, is a series of reactions that occur in the chloroplasts of plants during photosynthesis. The motor cycle and cell cycle are unrelated to cellular metabolism and energy production.

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  • 7. 

    In the electron transport chain, hydrogen ions are pumped across the mitochondrial membrane. What provides the energy to operate the protein pumps?

    • A.

      Electrons

    • B.

      ATP

    • C.

      Oxygen

    • D.

      Carbon dioxide

    Correct Answer
    A. Electrons
    Explanation
    Electrons provide the energy to operate the protein pumps in the electron transport chain. As electrons move through the chain, they transfer energy from one protein complex to another. This energy is used to pump hydrogen ions across the mitochondrial membrane, creating a concentration gradient. The flow of these ions back across the membrane through ATP synthase generates ATP, which is the energy currency of the cell. Therefore, while oxygen is the final electron acceptor in the chain and ATP is produced, it is the movement of electrons that directly powers the protein pumps.

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  • 8. 

    What enzyme is located at the end of the electron transport chain?

    • A.

      ATP synthase

    • B.

      Dehydrogenase

    • C.

      NADPH

    • D.

      Glycolase

    Correct Answer
    A. ATP synthase
    Explanation
    ATP synthase is the correct answer because it is the enzyme located at the end of the electron transport chain. This enzyme is responsible for the synthesis of ATP, the main energy currency of cells. It uses the energy generated from the flow of protons down their electrochemical gradient to convert ADP (adenosine diphosphate) and inorganic phosphate into ATP through a process called oxidative phosphorylation. ATP synthase acts as a molecular motor, rotating and catalyzing the production of ATP molecules.

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  • 9. 

    Which of the following is not a stage of cellular respiration?

    • A.

      Glycolysis

    • B.

      Electron transport chain

    • C.

      Krebs cycle

    • D.

      Calvin cycle

    Correct Answer
    D. Calvin cycle
    Explanation
    The Calvin cycle is not a stage of cellular respiration. It is a part of photosynthesis, which occurs in the chloroplasts of plants. The Calvin cycle is responsible for converting carbon dioxide into glucose using the energy from ATP and NADPH, which are produced during the light-dependent reactions of photosynthesis. In contrast, cellular respiration is the process by which cells break down glucose to produce ATP, and it consists of three stages: glycolysis, the Krebs cycle, and the electron transport chain.

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  • 10. 

    What provides the electron transport chain in cellular respiration with the energy it needs to function?

    • A.

      ATP synthase

    • B.

      Glycolysis

    • C.

      Chlorophyll

    • D.

      Krebs cycle

    Correct Answer
    D. Krebs cycle
    Explanation
    The Krebs cycle, also known as the citric acid cycle, is a series of chemical reactions that occur in the mitochondria of cells. It is an important part of cellular respiration and plays a key role in generating energy. During the Krebs cycle, acetyl-CoA molecules are broken down, releasing energy in the form of ATP. This energy is then used by the electron transport chain to function properly. Therefore, the Krebs cycle provides the electron transport chain with the energy it needs to carry out its function.

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  • 11. 

    The electron transport chain produces water and ATP. Where do the hydrogen atoms come from that are used to form water?

    • A.

      Carbon dioxide

    • B.

      NADH and FADH2

    • C.

      The Calvin Cycle

    • D.

      Oxygen

    Correct Answer
    B. NADH and FADH2
    Explanation
    NADH and FADH2 are molecules that carry high-energy electrons, which are derived from the breakdown of glucose during cellular respiration. These molecules donate their electrons to the electron transport chain, where the electrons are passed along a series of protein complexes. As the electrons move through the chain, they provide the energy needed to pump hydrogen ions (H+) across the inner mitochondrial membrane. This creates an electrochemical gradient, which drives the synthesis of ATP. At the end of the electron transport chain, the electrons combine with oxygen (O2) to form water (H2O). Therefore, the hydrogen atoms used to form water come from NADH and FADH2.

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  • 12. 

    Two products of the Krebs cycle are

    • A.

      Water and carbon dioxide.

    • B.

      ATP and carbon dioxide.

    • C.

      ATP and oxygen.

    • D.

      ADP and water.

    Correct Answer
    B. ATP and carbon dioxide.
    Explanation
    The Krebs cycle, also known as the citric acid cycle, is a series of chemical reactions that occur in the mitochondria of cells. It is an essential part of cellular respiration, which is the process by which cells generate energy. During the Krebs cycle, carbon dioxide is produced as a waste product, which is eventually exhaled by organisms. Additionally, ATP (adenosine triphosphate) is also produced as a result of the Krebs cycle. ATP is the primary energy currency of cells and is used for various cellular processes. Therefore, the correct answer is ATP and carbon dioxide.

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  • 13. 

    The part of cellular respiration in which glucose is broken down is called

    • A.

      Photosynthesis.

    • B.

      Aerobic respiration.

    • C.

      Electron transport.

    • D.

      Glycolysis.

    Correct Answer
    D. Glycolysis.
    Explanation
    Glycolysis is the correct answer because it is the process in cellular respiration where glucose is broken down into two molecules of pyruvate. This process occurs in the cytoplasm of the cell and does not require oxygen. Photosynthesis is the process by which plants convert sunlight into energy and is not related to the breakdown of glucose. Aerobic respiration and electron transport are other stages of cellular respiration, but they do not specifically refer to the breakdown of glucose.

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  • 14. 

    What is the main function of the Krebs cycle?

    • A.

      Breaking down pyruvate molecules to form molecules of NADH and oxygen

    • B.

      Forming citric acid to make NADH, water, and carbon dioxide

    • C.

      Producing molecules that carry high-energy electrons to the electron transport chain

    • D.

      Bonding coenzyme A to pyruvate

    Correct Answer
    C. Producing molecules that carry high-energy electrons to the electron transport chain
    Explanation
    The main function of the Krebs cycle is to produce molecules that carry high-energy electrons to the electron transport chain. The Krebs cycle, also known as the citric acid cycle, is a series of chemical reactions that occur in the mitochondria of cells. During this cycle, acetyl-CoA molecules are oxidized, producing NADH and FADH2, which carry high-energy electrons. These molecules then transfer the electrons to the electron transport chain, where they are used to generate ATP through oxidative phosphorylation.

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  • 15. 

    In the electron transport chain, energy from the Krebs cycle is used to pump hydrogen ions

    • A.

      Across the inner mitochondrial membrane.

    • B.

      Through the ATP synthase enzyme in the mitochondrial matrix.

    • C.

      Along a concentration gradient in the thylakoid.

    • D.

      Along the thylakoid membrane.

    Correct Answer
    A. Across the inner mitochondrial membrane.
    Explanation
    The electron transport chain is a series of protein complexes located in the inner mitochondrial membrane. During the Krebs cycle, high-energy electrons are generated and transferred to the electron transport chain. As these electrons pass through the protein complexes, hydrogen ions (protons) are pumped across the inner mitochondrial membrane, creating a concentration gradient. This gradient is essential for the production of ATP through ATP synthase, which is also located in the inner mitochondrial membrane. Therefore, the correct answer is that energy from the Krebs cycle is used to pump hydrogen ions across the inner mitochondrial membrane.

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  • 16. 

    Which process breaks down sugars to make ATP when oxygen is present?

    • A.

      Anaerobic respiration

    • B.

      Cellular respiration

    • C.

      Glycolysis

    • D.

      Photosynthesis

    Correct Answer
    B. Cellular respiration
    Explanation
    Cellular respiration is the correct answer because it is the process by which cells break down sugars, such as glucose, in the presence of oxygen to produce ATP (adenosine triphosphate), which is the main energy source for cellular activities. This process occurs in the mitochondria of cells and involves several stages, including glycolysis, the Krebs cycle, and the electron transport chain. Anaerobic respiration occurs in the absence of oxygen, glycolysis is the initial step of cellular respiration, and photosynthesis is the process by which plants convert sunlight into energy.

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  • 17. 

    Which of the following types of organisms uses cellular respiration for their cellular energy needs?

    • A.

      Eukaryotes

    • B.

      Plants only

    • C.

      Animals only

    • D.

      Prokaryotes

    Correct Answer
    A. Eukaryotes
    Explanation
    Eukaryotes use cellular respiration for their cellular energy needs. Cellular respiration is the process by which cells break down organic molecules, such as glucose, to produce ATP (adenosine triphosphate), the main energy molecule used by cells. Eukaryotes include organisms such as plants, animals, fungi, and protists, all of which have complex cellular structures and organelles, including mitochondria, where cellular respiration takes place. Prokaryotes, on the other hand, lack mitochondria and perform a different type of respiration called anaerobic respiration or fermentation.

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  • 18. 

    What is the function of oxygen in cellular respiration?

    • A.

      To deliver hydrogen ions to the electron transport chain

    • B.

      To pick up electrons at the end of the electron transport chain

    • C.

      To provide oxygen for the production of carbon dioxide

    • D.

      To give a source of energy to the Krebs cycle

    Correct Answer
    B. To pick up electrons at the end of the electron transport chain
    Explanation
    Oxygen is the final electron acceptor in the electron transport chain of cellular respiration. It picks up electrons from the chain and combines with hydrogen ions to form water. This process allows for the production of ATP, the main energy currency of the cell. Without oxygen, the electron transport chain would not be able to function properly, leading to a decrease in ATP production and ultimately cell death.

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  • 19. 

    Where does glycolysis take place?

    • A.

      Cytoplasm

    • B.

      Mitochondrial matrix

    • C.

      Mitochondrial inner membrane

    • D.

      Chloroplast

    Correct Answer
    A. Cytoplasm
    Explanation
    Glycolysis is the metabolic pathway that breaks down glucose into pyruvate. It is the first step in cellular respiration and occurs in the cytoplasm of the cell. This process does not require oxygen and is therefore considered anaerobic. The cytoplasm is the fluid-filled region of the cell where various cellular processes take place, including the breakdown of glucose during glycolysis. Therefore, the correct answer is cytoplasm.

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  • 20. 

    Which of the following statements best describes cellular respiration?

    • A.

      Sunlight and carbon dioxide are used to make ATP.

    • B.

      ATP and oxygen are used to make sugars and starches.

    • C.

      Carbon-based molecules from food and oxygen are used to make ATP.

    • D.

      ATP and carbon dioxide are used to make ADP and water.

    Correct Answer
    C. Carbon-based molecules from food and oxygen are used to make ATP.
    Explanation
    Cellular respiration is the process by which cells break down carbon-based molecules from food and combine them with oxygen to produce ATP, which is the energy currency of the cell. This process occurs in the mitochondria of cells and is essential for the release of energy needed for various cellular activities. The other options mentioned in the question either do not accurately describe cellular respiration or involve incorrect combinations of molecules.

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  • 21. 

    Which of the following are end products of glycolysis?

    • A.

      Two three-carbon molecules, ATP, and NAD+

    • B.

      Carbon dioxide, water, and ATP

    • C.

      NAD+, oxygen, and two ATP molecules

    • D.

      Pyruvate, NADH, and ATP

    Correct Answer
    D. Pyruvate, NADH, and ATP
    Explanation
    Glycolysis is the process in which glucose is broken down into pyruvate. NADH and ATP are also produced during glycolysis. Therefore, the end products of glycolysis are pyruvate, NADH, and ATP.

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  • 22. 

    In the diagram to the right, the structure labeled E is the ___.

    • A.

      Stroma

    • B.

      Chlorophyll

    • C.

      Granum

    • D.

      Thylakoid membranes

    Correct Answer
    D. Thylakoid membranes
    Explanation
    In the given diagram, the structure labeled E appears to be a series of interconnected membranes. These membranes are arranged in a stack-like structure, suggesting that they are thylakoid membranes. Thylakoid membranes are found within chloroplasts and are responsible for carrying out the light-dependent reactions of photosynthesis. They contain the pigment chlorophyll, which captures light energy and converts it into chemical energy. Therefore, the correct answer is thylakoid membranes.

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  • 23. 

    In the diagram to the right, the structure labeled C is the ___.

    • A.

      Stroma

    • B.

      Chlorophyll

    • C.

      Granum

    • D.

      Thylakoid membranes

    Correct Answer
    A. Stroma
    Explanation
    In the diagram to the right, the structure labeled C is the stroma. The stroma is the fluid-filled space inside the chloroplasts, where various metabolic reactions occur. It surrounds the thylakoid membranes, which are responsible for the light-dependent reactions of photosynthesis. The stroma contains enzymes and other molecules necessary for the synthesis of glucose during the light-independent reactions. Therefore, it is the correct answer in this context.

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  • 24. 

    In the diagram to the right, the structure labeled D is the ___.

    • A.

      Stroma

    • B.

      Chlorophyll

    • C.

      Granum

    • D.

      Thylakoid membranes

    Correct Answer
    C. Granum
    Explanation
    In the given diagram, the structure labeled D appears to be a stack of flattened sacs. This structure is characteristic of a granum, which is a stack of thylakoid membranes found in chloroplasts. The thylakoid membranes contain chlorophyll, which is responsible for capturing light energy during photosynthesis. Therefore, the correct answer is granum.

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  • 25. 

    The light-independent reactions of photosynthesis need

    • A.

      Carbon dioxide.

    • B.

      Oxygen.

    • C.

      Water.

    • D.

      Cellulose.

    Correct Answer
    A. Carbon dioxide.
    Explanation
    The light-independent reactions of photosynthesis, also known as the Calvin cycle, are responsible for converting carbon dioxide into glucose. These reactions occur in the stroma of the chloroplasts and do not require light. Carbon dioxide is used as a source of carbon atoms to build glucose molecules, which are then used for energy storage and growth in plants. Oxygen is produced as a byproduct of the light-dependent reactions, while water is used as an electron donor in the photosynthetic process. Cellulose, on the other hand, is a complex carbohydrate that serves as a structural component in plant cell walls and is not directly involved in the light-independent reactions.

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  • 26. 

    The purpose of the light reactions is to___.

    • A.

      Make ATP and NADPH for use in the Calvin cycle

    • B.

      To make oxygen

    • C.

      To split water

    • D.

      To make glucose

    Correct Answer
    A. Make ATP and NADPH for use in the Calvin cycle
    Explanation
    The purpose of the light reactions is to make ATP and NADPH for use in the Calvin cycle. During the light reactions, light energy is absorbed by chlorophyll and other pigments in the thylakoid membranes of the chloroplasts. This energy is used to generate ATP through photophosphorylation and to produce NADPH through the reduction of NADP+. Both ATP and NADPH are then utilized in the Calvin cycle, where they provide the energy and reducing power needed for the fixation of carbon dioxide and the synthesis of glucose.

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  • 27. 

    What is the ultimate source of energy in almost every food chain?

    • A.

      The sun

    • B.

      Producers

    • C.

      Consumers

    • D.

      Detritivores

    Correct Answer
    A. The sun
    Explanation
    The ultimate source of energy in almost every food chain is the sun. The sun provides light and heat energy, which is captured by producers (such as plants) through photosynthesis. Producers convert this solar energy into chemical energy in the form of glucose. Consumers, including herbivores, carnivores, and omnivores, obtain their energy by consuming these producers or other consumers. Detritivores, which feed on dead and decaying organic matter, also indirectly rely on the sun's energy as it is transferred through the food chain.

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  • 28. 

    What are the products of photosynthesis?

    • A.

      Carbon dioxide and water

    • B.

      Glucose and oxygen

    • C.

      Water and glucose

    • D.

      Carbon dioxide and oxygen

    Correct Answer
    B. Glucose and oxygen
    Explanation
    Photosynthesis is the process by which plants convert carbon dioxide and water into glucose and oxygen using sunlight as an energy source. Glucose is a sugar molecule that serves as the primary source of energy for plants, while oxygen is released as a byproduct. Therefore, the correct answer is glucose and oxygen.

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  • 29. 

    In the light-independent reactions of photosynthesis,

    • A.

      Carbon dioxide enters the Calvin cycle and sugars are made.

    • B.

      Water is broken down and oxygen is released.

    • C.

      NADPH is produced and transferred to photosystem I.

    • D.

      Electrons are energized and used to pump H+ ions.

    Correct Answer
    A. Carbon dioxide enters the Calvin cycle and sugars are made.
    Explanation
    In the light-independent reactions of photosynthesis, carbon dioxide enters the Calvin cycle and sugars are made. This is because during the Calvin cycle, carbon dioxide molecules are combined with molecules of a five-carbon sugar called ribulose bisphosphate (RuBP) to form an unstable six-carbon compound. This compound then breaks down into two molecules of a three-carbon compound called 3-phosphoglycerate (PGA). The PGA molecules are then converted into a three-carbon sugar called glyceraldehyde-3-phosphate (G3P), which can be used to synthesize glucose and other sugars. Therefore, the correct answer is that carbon dioxide enters the Calvin cycle and sugars are made.

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  • 30. 

    What is the relationship between the photosystems and the Calvin cycle?

    • A.

      The photosystems produce ATP synthase for the Calvin cycle.

    • B.

      The photosystems transfer hydrogen ions and carbon dioxide to the Calvin cycle.

    • C.

      The photosystems transfer energy to the Calvin cycle through ATP and NADPH.

    • D.

      The photosystems build sugars with the carbon dioxide produced by the Calvin cycle.

    Correct Answer
    C. The photosystems transfer energy to the Calvin cycle through ATP and NADPH.
    Explanation
    The photosystems transfer energy to the Calvin cycle through ATP and NADPH. This is because during photosynthesis, the photosystems capture light energy and convert it into chemical energy in the form of ATP and NADPH. These energy-rich molecules are then used in the Calvin cycle, which is the process by which plants convert carbon dioxide into sugars. ATP and NADPH provide the necessary energy for the Calvin cycle to occur and facilitate the synthesis of sugars.

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  • 31. 

    Which of the following statements best describes the process of photosynthesis?

    • A.

      Plants use oxygen to make simple sugars.

    • B.

      Chlorophyll builds sugars in the thylakoid membrane.

    • C.

      Light breaks down water molecules and releases carbon dioxide.

    • D.

      Chloroplasts absorb sunlight and store chemical energy.

    Correct Answer
    D. Chloroplasts absorb sunlight and store chemical energy.
    Explanation
    Chloroplasts are the organelles in plant cells responsible for photosynthesis. During photosynthesis, chloroplasts absorb sunlight and convert it into chemical energy in the form of glucose or other sugars. This process occurs in the chloroplast's thylakoid membrane, where chlorophyll molecules capture the energy from sunlight and use it to power the synthesis of sugars. Therefore, the statement "Chloroplasts absorb sunlight and store chemical energy" best describes the process of photosynthesis.

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  • 32. 

    What is the term for an organism that makes its own source of chemical energy?

    • A.

      Decomposer

    • B.

      Producer

    • C.

      Chloroplast

    • D.

      Protist

    Correct Answer
    B. Producer
    Explanation
    A producer is an organism that is able to synthesize its own source of chemical energy through the process of photosynthesis or chemosynthesis. These organisms, such as plants and some bacteria, are capable of converting sunlight or inorganic compounds into usable energy in the form of glucose. This ability to produce their own energy sets them apart from other organisms that rely on consuming other organisms or organic matter for energy.

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  • 33. 

    The main light-absorbing molecules found in plant leaves are called

    • A.

      Chloroplasts

    • B.

      Thylakoids

    • C.

      Chlorophyll

    • D.

      Grana

    Correct Answer
    C. Chlorophyll
    Explanation
    Chlorophyll is the correct answer because it is the main light-absorbing pigment found in plant leaves. It is responsible for capturing sunlight and converting it into chemical energy through the process of photosynthesis. Chlorophyll molecules are located within the chloroplasts, which are the organelles where photosynthesis takes place. Thylakoids are membrane structures within the chloroplasts where the chlorophyll molecules are embedded. Grana are stacks of thylakoids. While all of these terms are related to the process of photosynthesis, chlorophyll specifically refers to the light-absorbing molecules.

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  • 34. 

    The function of the light-dependent reactions is to

    • A.

      Build sugars.

    • B.

      Capture and transfer energy.

    • C.

      Release carbon dioxide.

    • D.

      Form water molecules.

    Correct Answer
    B. Capture and transfer energy.
    Explanation
    The light-dependent reactions in photosynthesis occur in the thylakoid membrane of chloroplasts and involve the absorption of light energy by chlorophyll. This energy is then used to convert water into oxygen and high-energy molecules such as ATP and NADPH. These molecules are essential for the subsequent light-independent reactions, where they provide the energy and reducing power needed to build sugars. Therefore, the primary function of the light-dependent reactions is to capture and transfer energy, making the given answer correct.

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  • 35. 

    Where do the hydrogen ions for the photosystems of the light-dependent reactions come from?

    • A.

      Sugars

    • B.

      Sunlight

    • C.

      Acids

    • D.

      Water

    Correct Answer
    D. Water
    Explanation
    The hydrogen ions for the photosystems of the light-dependent reactions come from water. During photosynthesis, water molecules are split in a process called photolysis, releasing oxygen, electrons, and hydrogen ions. The electrons are used in the photosystems to generate energy, while the hydrogen ions contribute to the formation of a proton gradient that drives ATP synthesis. This process is essential for the production of energy-rich molecules, such as glucose, in plants.

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  • 36. 

    Which phrase best describes the electron transport chain in photosynthesis?

    • A.

      A chain of photosynthetic proteins located in the stroma

    • B.

      A collection of enzymes used to make ADP

    • C.

      A series of proteins located in the thylakoid membrane

    • D.

      A group of enzymes that carries energy to the Calvin cycle

    Correct Answer
    C. A series of proteins located in the thylakoid membrane
    Explanation
    The electron transport chain in photosynthesis is a series of proteins located in the thylakoid membrane. This chain is responsible for transferring electrons and generating a proton gradient, which is used to produce ATP during the light-dependent reactions of photosynthesis. The thylakoid membrane is where the pigments and protein complexes involved in photosynthesis are located, making it the ideal site for the electron transport chain to occur.

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  • 37. 

    The process by which plants use sunlight to make glucose is called ___.

    • A.

      Photosynthesis

    • B.

      Cellular respiration

    • C.

      The cell cycle

    • D.

      Mitosis

    Correct Answer
    A. Photosynthesis
    Explanation
    Photosynthesis is the correct answer because it is the process by which plants convert sunlight, water, and carbon dioxide into glucose and oxygen. During photosynthesis, plants use chlorophyll in their cells to capture sunlight energy and convert it into chemical energy in the form of glucose. This process is essential for plants to produce food and release oxygen into the atmosphere. Cellular respiration, the cell cycle, and mitosis are unrelated processes that do not involve the conversion of sunlight into glucose.

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  • 38. 

    Which of the following takes place in the light-dependent reactions of photosynthesis?

    • A.

      Sugars are made.

    • B.

      Energy is captured.

    • C.

      Chlorophyll is pumped.

    • D.

      Carbon dioxide is formed.

    Correct Answer
    B. Energy is captured.
    Explanation
    In the light-dependent reactions of photosynthesis, energy is captured from sunlight by chlorophyll molecules in the chloroplasts of plant cells. This captured energy is then used to convert water molecules into oxygen and high-energy molecules called ATP and NADPH. These energy-rich molecules are essential for the subsequent dark reactions of photosynthesis, where sugars are made using carbon dioxide. Therefore, the correct answer is "Energy is captured."

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  • 39. 

    Which process breaks down sugars to make ATP when oxygen is NOT present?

    • A.

      Anaerobic respiration (a.k.a. Fermentation)

    • B.

      Cellular respiration

    • C.

      Glycolysis

    • D.

      Photosynthesis

    Correct Answer
    A. Anaerobic respiration (a.k.a. Fermentation)
    Explanation
    Anaerobic respiration, also known as fermentation, is the process that breaks down sugars to produce ATP when oxygen is not present. This process occurs in the absence of oxygen and is a less efficient way to produce ATP compared to cellular respiration. In anaerobic respiration, glucose is broken down through glycolysis, which produces a small amount of ATP and waste products such as lactic acid or ethanol. This process is commonly observed in microorganisms, muscle cells during intense exercise, and certain types of bacteria and yeast.

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  • 40. 

    Which of the following statements is true for all cells?

    • A.

      They use solar energy.

    • B.

      They use photosynthesis.

    • C.

      They use chemical energy.

    • D.

      They use chemosynthesis.

    Correct Answer
    C. They use chemical energy.
    Explanation
    All cells use chemical energy because it is required for their basic functions such as metabolism, growth, and reproduction. Chemical energy is obtained through the breakdown of molecules such as glucose during cellular respiration. This process releases energy in the form of ATP, which is used by cells to carry out various biochemical reactions. While some cells, like plant cells, can also use solar energy through photosynthesis, not all cells have access to sunlight. Therefore, the statement that all cells use chemical energy is true for all types of cells.

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  • 41. 

    Which phrase best describes the function of the ATP molecule?

    • A.

      Absorbs energy

    • B.

      Converts energy

    • C.

      Stores and transfers energy

    • D.

      Destroys

    Correct Answer
    C. Stores and transfers energy
    Explanation
    The ATP molecule is known as the "energy currency" of the cell because it stores and transfers energy. ATP is synthesized during cellular respiration and acts as a source of energy for various cellular processes. When ATP is hydrolyzed, it releases energy that can be used by the cell to perform work. Additionally, ATP can transfer its phosphate groups to other molecules, thereby transferring energy to those molecules. Therefore, the phrase "stores and transfers energy" accurately describes the function of the ATP molecule.

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  • 42. 

    Where does the chemical energy to produce ATP come from?

    • A.

      The conversion of ATP to ADP.

    • B.

      The use of chemicals from the environment to build sugars.

    • C.

      The addition of a phosphate group to ATP.

    • D.

      The breakdown of carbon-based molecules into smaller molecules.

    Correct Answer
    D. The breakdown of carbon-based molecules into smaller molecules.
    Explanation
    The correct answer is the breakdown of carbon-based molecules into smaller molecules. ATP is produced through cellular respiration, where carbon-based molecules such as glucose are broken down into smaller molecules. This process releases energy, which is used to convert ADP (adenosine diphosphate) into ATP (adenosine triphosphate). Therefore, the chemical energy to produce ATP comes from the breakdown of carbon-based molecules.

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  • 43. 

    Energy is released from ATP molecules for cellular processes when it ...

    • A.

      Has a phosphate group removed.

    • B.

      Stores an extra phosphate group.

    • C.

      Converts a phosphate group to ADP.

    • D.

      Produces a sugar molecule.

    Correct Answer
    A. Has a phosphate group removed.
    Explanation
    ATP (adenosine triphosphate) is the main energy molecule in cells. It stores energy in its phosphate bonds. When a phosphate group is removed from ATP, it becomes ADP (adenosine diphosphate), releasing energy that can be used for various cellular processes. Therefore, the correct answer is "has a phosphate group removed."

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  • 44. 

    Which of the following is the source of energy used in chemosynthesis?

    • A.

      Sunlight

    • B.

      Heat from hydrothermal vents

    • C.

      Chemical compounds

    • D.

      Amino acids

    Correct Answer
    C. Chemical compounds
    Explanation
    Chemosynthesis is a process in which organisms use chemical compounds as a source of energy to produce food. Unlike photosynthesis, which uses sunlight as an energy source, chemosynthesis occurs in environments where sunlight is not available, such as deep-sea hydrothermal vents or underground caves. In these environments, bacteria and other microorganisms convert chemical compounds, such as hydrogen sulfide or methane, into usable energy through chemosynthesis. Therefore, chemical compounds are the source of energy used in chemosynthesis.

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  • 45. 

    A molecule of ATP is made of ...

    • A.

      Adenosine, ribose, and three phosphate groups.

    • B.

      Adenine, ribose, and two phosphate groups.

    • C.

      Adenosine, deoxyribose, and three phosphate groups.

    • D.

      Adenosine, ribose, and two phosphate groups.

    Correct Answer
    A. Adenosine, ribose, and three phosphate groups.
    Explanation
    A molecule of ATP is made of adenosine, ribose, and three phosphate groups. Adenosine is a nucleoside that consists of adenine and ribose. Ribose is a sugar molecule that is part of the nucleotide structure. ATP (adenosine triphosphate) is the primary energy currency of cells and is involved in various cellular processes. It contains three phosphate groups, which are responsible for storing and releasing energy during cellular reactions.

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  • 46. 

    How is ATP transformed into ADP?

    • A.

      A phosphate group is added

    • B.

      A phosphate group is removed

    • C.

      Sugar is broken down into pyruvate

    • D.

      Sunlight is absorbed

    Correct Answer
    B. A phosphate group is removed
    Explanation
    ATP (adenosine triphosphate) is a molecule that stores and provides energy for cellular processes. When ATP is transformed into ADP (adenosine diphosphate), a phosphate group is removed from ATP, resulting in the release of energy. This process is known as hydrolysis, where a water molecule is used to break the bond between the phosphate groups. The removal of a phosphate group converts ATP into ADP, making the energy stored in ATP available for various cellular activities.

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  • 47. 

    What is the part labeled A in this diagram?

    • A.

      Adenosine

    • B.

      Ribose

    • C.

      Phosphate

    • D.

      ATP

    Correct Answer
    A. Adenosine
    Explanation
    The part labeled A in the diagram is adenosine. Adenosine is a nucleoside composed of adenine and ribose. It is an important component of nucleic acids like DNA and RNA, as well as energy-carrying molecules like ATP.

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  • 48. 

    What is the part labeled C in this diagram?

    • A.

      Adenosine

    • B.

      Ribose

    • C.

      Phosphate

    • D.

      ATP

    Correct Answer
    C. Phosphate
    Explanation
    The part labeled C in this diagram is phosphate. Phosphate is an essential component of adenosine triphosphate (ATP), which is a molecule that stores and transfers energy in cells. It consists of a phosphate group, a ribose sugar, and an adenine base. In this diagram, phosphate is shown as a separate part, indicating its importance in ATP.

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  • 49. 

    What is the part labeled B in this diagram?

    • A.

      Adenosine

    • B.

      Ribose

    • C.

      Phosphate

    • D.

      ATP

    Correct Answer
    B. Ribose
    Explanation
    The part labeled B in the diagram is ribose. Ribose is a type of sugar that is a component of RNA (ribonucleic acid) molecules. It is a 5-carbon sugar that plays a crucial role in the structure and function of RNA.

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  • 50. 

    What molecule is pictured in this diagram?

    • A.

      Adenosine

    • B.

      Ribose

    • C.

      Phosphate

    • D.

      ATP

    Correct Answer
    D. ATP
    Explanation
    The molecule pictured in the diagram is ATP (adenosine triphosphate). ATP is a nucleotide that is commonly referred to as the "energy currency" of the cell. It is composed of three phosphate groups, a ribose sugar, and an adenine base. ATP is responsible for storing and transferring energy within cells, making it essential for various cellular processes such as muscle contraction, DNA synthesis, and active transport.

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