Biology 101-09 Practice Questions

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Biology 101-09 Practice Questions - Quiz

Purdue University Calumet Biology 101-09 Practice Final Exam Questions


Questions and Answers
  • 1. 

    A major function of the mitochondrial inner membrane is the conversion of energy from electrons to the stored energy of the phosphate bond in ATP. To accomplish this function, this membrane must have all of the following features except

    • A.

      Proteins to accept electrons from NADH

    • B.

      The electron transport chain of proteins.

    • C.

      High permeability to protons

    • D.

      Proton pumps embedded in the membrane

    • E.

      Integral, transverse ATP synthase

    Correct Answer
    C. High permeability to protons
    Explanation
    The mitochondrial inner membrane has proteins to accept electrons from NADH, the electron transport chain of proteins, proton pumps embedded in the membrane, and integral, transverse ATP synthase. However, it does not have high permeability to protons. Proton permeability would disrupt the electrochemical gradient necessary for ATP synthesis.

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  • 2. 

    In mitochondria, chemiosmosis translocates protons from the matrix into the intermembrane space, whereas in chloroplasts, chemiosmosis translocates protons from

    • A.

      The stroma into the thylakoid compartment

    • B.

      The light reactions to the Calvin cycle

    • C.

      The matrix to the stroma

    • D.

      The stroma to the chlorophyll

    • E.

      The intermembrane space to the matrix

    Correct Answer
    A. The stroma into the thylakoid compartment
    Explanation
    In chloroplasts, chemiosmosis translocates protons from the stroma into the thylakoid compartment. This process is essential for the production of ATP during photosynthesis. The movement of protons across the thylakoid membrane creates an electrochemical gradient, which is then used by ATP synthase to generate ATP. This process is similar to the chemiosmosis that occurs in mitochondria, where protons are translocated from the matrix into the intermembrane space to generate ATP during cellular respiration.

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  • 3. 

    The first law of thermodynamics states that energy can be neither created nor destroyed. For living organisms, which of the following is an important consequence of the first law?

    • A.

      The energy content of an organism is constant

    • B.

      Organisms are unable to transform energy

    • C.

      Life does not obey the first law of thermodynamics

    • D.

      The entropy of an organism decreases with time as the organism grows in complexity

    • E.

      The organism ultimately must obtain all of the necessary energy for life from its environment

    Correct Answer
    E. The organism ultimately must obtain all of the necessary energy for life from its environment
    Explanation
    The first law of thermodynamics states that energy can be neither created nor destroyed. This means that the total energy within a closed system, such as an organism, remains constant. However, living organisms require energy to carry out their biological processes. Therefore, the organism must obtain all the necessary energy for life from its environment, as it cannot create energy internally. This is an important consequence of the first law of thermodynamics for living organisms.

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  • 4. 

    Consider the following: Succinic acid dehydrogenase catalyzes the reaction of succinic acid to fumaric acid. The reaction is inhibited by malonic acid, which resembles succinic acid by cannot be catalyzed by succinic dehydrogenase. Increasing the ratio of succinic acid to malonic acid reduces the inhibitory effect of malonic acid. Which of the following is correct?

    • A.

      Succinic acid dehydrogenase is the enzyme, and fumaric acid is the substrate

    • B.

      Fumaric acid is the product and malonic acid is a non competitive inhibitor

    • C.

      Succinic acid dehydrogenase is the enzyme, and malonic acid is the substrate

    • D.

      Malonic acid is the product, and fumaric acid is a competitive inhibitor

    • E.

      Succinic acid is the substrate, and fumaric acid is the product

    Correct Answer
    E. Succinic acid is the substrate, and fumaric acid is the product
    Explanation
    The given information states that succinic acid dehydrogenase catalyzes the reaction of succinic acid to fumaric acid. This indicates that succinic acid is the substrate, and fumaric acid is the product of the reaction.

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  • 5. 

    The next questions are based on the following information. A series of enzymes catalyze the reaction X→Y→Z→A. Product A binds to the enzyme that converts X to Y at a position remote from its active site. This binding decreases the activity of the enzyme.Substance A functions as

    • A.

      A coenzyme

    • B.

      An intermediate

    • C.

      A competitive inhibitor

    • D.

      The substrate

    • E.

      An allosteric inhibitor

    Correct Answer
    E. An allosteric inhibitor
    Explanation
    In this scenario, product A binds to the enzyme at a position away from its active site. This type of binding is characteristic of an allosteric inhibitor. An allosteric inhibitor is a molecule that binds to an enzyme at a location other than the active site, causing a conformational change in the enzyme's structure. This change reduces the enzyme's activity, inhibiting its function. Therefore, substance A in this case is functioning as an allosteric inhibitor.

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  • 6. 

    Some photosynthetic organisms contain chloroplasts that lack photosystem II, yet are able to survive. The best way to detect the lack of photosystem II in these organisms would be

    • A.

      To test for CO2 fixation in the dark

    • B.

      To determine if they have thylakoids in the chloroplasts

    • C.

      To test for production of either sucrose or starch

    • D.

      To test for liberation of O2 in the light

    • E.

      To do experiments to generate an action spectrum

    Correct Answer
    D. To test for liberation of O2 in the light
    Explanation
    The best way to detect the lack of photosystem II in these organisms would be to test for liberation of O2 in the light. Photosystem II is responsible for the initial step of photosynthesis, which involves the splitting of water molecules and the release of oxygen. If an organism lacks photosystem II, it will not be able to produce oxygen in the light. Therefore, testing for the liberation of O2 in the light can indicate whether or not photosystem II is present in the chloroplasts of these organisms.

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  • 7. 

    Use the following information to answer the question below. Thomas Engelmann illuminated a filament of algae with light that passed through a prism, thus exposing different segments to algae to different wavelengths of light. He added aerobic bacteria and then noted in which areas the bacteria congregated. He noted that the largest groups were found in the areas illuminated by the red and blue light.An outcome of this experiment was to help determine

    • A.

      The relationship between heterotrophic and autotrophic organisms

    • B.

      The relationship between wavelengths of light and the rate of aerobic respiration

    • C.

      The relationship between the concentration of carbon dioxide and the rate of photosynthesis

    • D.

      The relationship between wavelengths of light and the oxygen released during photosynthesis

    • E.

      The relationship between wavelengths of light and the amount of heat released

    Correct Answer
    D. The relationship between wavelengths of light and the oxygen released during photosynthesis
    Explanation
    The experiment conducted by Thomas Engelmann involved illuminating different segments of algae with different wavelengths of light. He observed that the largest groups of aerobic bacteria congregated in the areas illuminated by red and blue light. This suggests that these wavelengths of light are most effective in stimulating photosynthesis, as the bacteria were attracted to the areas where oxygen was being released. Therefore, the experiment helped determine the relationship between wavelengths of light and the oxygen released during photosynthesis.

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  • 8. 

    Correct statements regarding ATP includeI. ATP serves as a main energy shuttle inside cells.II. ATP drives endergonic reaction in the cell by the enzymatic transfer of the phosphate group to specific reactants.III. The regeneration of ATP from ADP and phosphate is an endergonic reaction

    • A.

      I only

    • B.

      II only

    • C.

      III only

    • D.

      I and III only

    • E.

      I, II, and III

    Correct Answer
    E. I, II, and III
    Explanation
    ATP serves as a main energy shuttle inside cells, meaning it is responsible for transferring energy within the cell. It also drives endergonic reactions by transferring a phosphate group to specific reactants through enzymatic reactions. The regeneration of ATP from ADP and phosphate is an endergonic reaction, meaning it requires energy input. Therefore, all three statements are correct.

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  • 9. 

    Because bundle-sheath cells are relatively protected from atmospheric oxygen, the level of __________ is held to a minimum in C4 plants.

    • A.

      Photosynthesis

    • B.

      Photorespiration

    • C.

      Glycolysis

    • D.

      Decarboxylation of malic acid

    • E.

      Oxidative phosphorylation

    Correct Answer
    B. Photorespiration
    Explanation
    In C4 plants, bundle-sheath cells are located deep within the leaf and are surrounded by mesophyll cells. This arrangement helps to minimize the exposure of bundle-sheath cells to atmospheric oxygen. Photorespiration is a process that occurs in the presence of oxygen and can be detrimental to photosynthesis. Therefore, in C4 plants, the level of photorespiration is held to a minimum in order to optimize the efficiency of photosynthesis.

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  • 10. 

    The question below is based on the stages of glucose oxidation listed below.A. stage I: glycolysisB. stage II: oxidation of pyruvate to acetyl CoAC. stage III: Krebs cycleD. stage IV: oxidative phosphorylation (chemiosmosis)Carbon dioxide is release during which stage(s)?

    • A.

      Stage III only

    • B.

      Stages III and IV

    • C.

      Stages I, II, and III

    • D.

      Stages II and III

    • E.

      Stages II, III, and IV

    Correct Answer
    D. Stages II and III
    Explanation
    During stage II, pyruvate is oxidized to acetyl CoA, and during stage III (Krebs cycle), acetyl CoA is further oxidized, resulting in the release of carbon dioxide. Therefore, carbon dioxide is released during stages II and III of glucose oxidation.

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  • 11. 

    Carbon dioxide (CO2) is released during which of the following stages of cellular respiration?

    • A.

      Fermentation and glycolysis

    • B.

      Glycolysis and the oxidation of pyrubate to acetyl CoA

    • C.

      The citric acid cycle and oxidative phosphorylation

    • D.

      Oxidation of pyruvate to acetyl CoA and the citric acid cycle

    • E.

      Oxidative phosphorylation and fermentation

    Correct Answer
    D. Oxidation of pyruvate to acetyl CoA and the citric acid cycle
    Explanation
    During cellular respiration, carbon dioxide (CO2) is released during the oxidation of pyruvate to acetyl CoA and the citric acid cycle. In the first step, pyruvate is converted into acetyl CoA, releasing one molecule of CO2. Then, during the citric acid cycle, acetyl CoA is further broken down, resulting in the release of two more molecules of CO2. Therefore, the correct answer is "oxidation of pyruvate to acetyl CoA and the citric acid cycle."

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  • 12. 

    Which of the following statements regarding events in the functioning of photosystem II is false?

    • A.

      The electron vacancies in P680 are filled by electrons derived from water

    • B.

      The excitation is pased along to a molecule of P680 chlorophyll in the photosynthetic unit

    • C.

      The P680 chlorophyll donates a pair of protons to NADPH, which is thus converted to NADP+

    • D.

      Light energy excites electrons in an antenna pigment in a photosynthetic unit

    • E.

      The splitting of water yields molecular oxygen as a by-product

    Correct Answer
    C. The P680 chlorophyll donates a pair of protons to NADPH, which is thus converted to NADP+
    Explanation
    The P680 chlorophyll donates a pair of protons to NADPH, which is thus converted to NADP+. This statement is false because it is the P680 chlorophyll that donates a pair of electrons, not protons, to NADP+ in order to convert it to NADPH. Protons are involved in the process of chemiosmosis, where they are pumped across the thylakoid membrane to create a proton gradient that drives ATP synthesis.

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  • 13. 

    CAM plants can keep stomates closed in daytime, thus reducing loss of water. They can do this because they

    • A.

      Use the enzyme phosphofructokinase, which outcompetes rubisco for CO2

    • B.

      Fix CO2 into organic acids during the night

    • C.

      Fix CO2 into sugars in the bundle-sheath cells

    • D.

      Use photosystems I and II at night

    • E.

      Fix CO2 into pyruvic acid in the mesophyll cells

    Correct Answer
    B. Fix CO2 into organic acids during the night
    Explanation
    CAM plants have a unique adaptation where they fix CO2 into organic acids during the night. This allows them to keep their stomates closed during the day, reducing water loss through transpiration. By fixing CO2 into organic acids at night, CAM plants are able to store carbon dioxide and perform photosynthesis during the day using the stored acids. This strategy helps them survive in arid environments with limited water availability.

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  • 14. 

    A young relative of yours has never had much energy. He goes to a doctor for help and is sent to the hospital for some tests. There they discover his mitochondria can use only fatty acids and amino acids for respiration, and his cells produce more lactate than normal. Of the following, which is the best explanation of his condition>

    • A.

      His cells contain something that inhibits oxygen use in his mitochondria

    • B.

      His cells cannot move NADH from glycolysis into the mitochondria

    • C.

      His cells have a defective electron transport chain, so glucose goes to lactate instead of to acetyl CoA

    • D.

      His cells lack the enzyme in glycolysis that forms pyruvate

    • E.

      His mitochondria lack the transport protein that moves pyruvate across the outer mitochondrial membrane

    Correct Answer
    E. His mitochondria lack the transport protein that moves pyruvate across the outer mitochondrial membrane
    Explanation
    The given scenario indicates that the individual's cells produce more lactate than normal, which suggests that glucose is being converted to lactate instead of being metabolized through the mitochondria. This indicates a defect in the process of converting glucose to acetyl CoA, which occurs in the mitochondria. The correct answer states that his mitochondria lack the transport protein that moves pyruvate across the outer mitochondrial membrane. This deficiency would prevent pyruvate, the end product of glycolysis, from entering the mitochondria and undergoing further metabolism. As a result, glucose is converted to lactate instead of acetyl CoA, leading to the observed symptoms of low energy.

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  • 15. 

    The electron transport chain energy is used to pump H+ ions into which location?

    • A.

      Cytosol

    • B.

      Mitochondrial outer membrane

    • C.

      Mitochondrial inner membrane

    • D.

      Mitochondrial intermembrance space

    • E.

      Mitochondrial matrix

    Correct Answer
    D. Mitochondrial intermembrance space
    Explanation
    The electron transport chain is a series of protein complexes located in the inner mitochondrial membrane. As electrons are passed along the chain, energy is released and used to pump hydrogen ions (H+) from the mitochondrial matrix to the intermembrane space. This creates a concentration gradient of H+ ions, which is used to generate ATP through ATP synthase. Therefore, the correct answer is the mitochondrial intermembrane space.

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  • 16. 

    Chemical equilibrium is relatively rare in living cells. Which of the following could be an example of a reaction at chemical equilibrium in a cell?

    • A.

      A chemical reaction in which both the reactants and products are only used in a metabolic pathway that is completely inactive

    • B.

      An endergonic reaction in a active metabolic pathway where the energy for that reaction is supplied only by heat from the environment

    • C.

      A chemical reaction in which the entropy change in the reaction is just balanced by an opposite entropy change in the cell's surroundings

    • D.

      A reaction in which the free energy at equilibrium is higher than the energy content at any point away from equilibrium

    • E.

      There is no possibility of having chemical equilibrium in any living cell

    Correct Answer
    A. A chemical reaction in which both the reactants and products are only used in a metabolic pathway that is completely inactive
    Explanation
    This answer suggests that in a cell, there is a chemical reaction where both the reactants and products are present, but they are not actively participating in any metabolic pathway. This means that the reaction is not progressing in either the forward or reverse direction, resulting in a state of chemical equilibrium. The reactants and products are essentially in a balanced state, with no net change occurring.

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  • 17. 

    All of the following statements are true except:

    • A.

      Thylakoid membranes contain the photosynthetic pigments

    • B.

      The O2 released during photosynthesis comes from water

    • C.

      Glyceraldehyde phosphate is produced only in the light reactions of photosynthesis

    • D.

      When chlorophyll is reduced, it gains electrons

    • E.

      The light reactions of photosynthesis provide the energy for the Calvin cycle

    Correct Answer
    C. Glyceraldehyde phosphate is produced only in the light reactions of photosynthesis
    Explanation
    The statement "glyceraldehyde phosphate is produced only in the light reactions of photosynthesis" is incorrect. Glyceraldehyde phosphate is actually produced in the dark reactions of photosynthesis, also known as the Calvin cycle. In the Calvin cycle, carbon dioxide is fixed and converted into glyceraldehyde phosphate using the ATP and NADPH produced in the light reactions. Therefore, this statement is not true.

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  • 18. 

    Assume a thylakoid is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma. This damage will have the most direct effect on which of the following processes?

    • A.

      The reduction of NADP+

    • B.

      The synthesis of ATP

    • C.

      The flow of electrons from photosystem II to photosystem I

    • D.

      The splitting of water

    • E.

      The absorption of light energy by chlorophyll

    Correct Answer
    B. The synthesis of ATP
    Explanation
    If a thylakoid is punctured and the interior is no longer separated from the stroma, it will directly affect the synthesis of ATP. This is because the thylakoid membrane is where the electron transport chain occurs, which generates a proton gradient across the membrane. This proton gradient is necessary for ATP synthase to produce ATP through chemiosmosis. Without a intact thylakoid membrane, the proton gradient cannot be maintained and the synthesis of ATP cannot occur efficiently.

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  • 19. 

    All of the following statements are representative of the second law of thermodynamics except

    • A.

      Systems tend to rearrange themselves toward greater entropy

    • B.

      Every time energy changes form, there is a decrease in entropy

    • C.

      Highly organized systems require energy for their maintenance

    • D.

      Energy transfers are always accompanied by some loss

    • E.

      Heat energy represents lost energy to most systems

    Correct Answer
    B. Every time energy changes form, there is a decrease in entropy
    Explanation
    The second law of thermodynamics states that the entropy of an isolated system tends to increase over time. Entropy is a measure of the disorder or randomness in a system. The statement "every time energy changes form, there is a decrease in entropy" contradicts this law because energy changes can lead to an increase in entropy. For example, when energy is converted from a concentrated form (such as chemical energy in fuel) to a dispersed form (such as heat energy), the entropy of the system increases. Therefore, this statement does not align with the second law of thermodynamics.

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  • 20. 

    All of the following statements are correct regarding the Calvin cycle of photosynthesis except:

    • A.

      One of the end products is glyceraldehyde phosphate

    • B.

      The 5-carbon sugar RuBP is constantly being regenerated

    • C.

      These reactions begin soon after sundown and end before sunrise

    • D.

      The energy source utilized is the ATP and NADPH obtained through the light reaction

    Correct Answer
    C. These reactions begin soon after sundown and end before sunrise
    Explanation
    The given statement that is not correct regarding the Calvin cycle of photosynthesis is "these reactions begin soon after sundown and end before sunrise." The Calvin cycle does not have a specific time frame and can occur during both day and night. The cycle is not dependent on sunlight and can continue as long as the necessary substrates and enzymes are available. Therefore, the timing of the Calvin cycle is not restricted to the nighttime hours.

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  • 21. 

    A new flower species has a unique photosynthetic pigment. The leaves of this plant appear to be reddish yellow. What wavelengths of visible light are not being absorbed by this pigment?

    • A.

      Green and yellow

    • B.

      Blue, green, and red

    • C.

      Blue and violet

    • D.

      Red and yellow

    • E.

      Green, blue and violet

    Correct Answer
    D. Red and yellow
    Explanation
    The correct answer is red and yellow. The leaves of the plant appear reddish yellow, indicating that the pigment in the plant is absorbing all other colors of visible light except for red and yellow. Therefore, the wavelengths of red and yellow light are not being absorbed by this pigment.

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  • 22. 

    During aerobic respiration, electrons travel downhill in which sequence?

    • A.

      Food→NADH→electron transport chain→oxygen

    • B.

      Food→Krebs cycle→ATP→NAD+

    • C.

      Food→glycolysis→Krebs cycle→NADH→ATP

    • D.

      Glucose→ATP→oxygen

    • E.

      Glucose→ATP→electron transport chain→NADH

    Correct Answer
    A. Food→NADH→electron transport chain→oxygen
    Explanation
    During aerobic respiration, electrons travel downhill in the sequence of food being broken down to produce NADH, which then carries the electrons to the electron transport chain. The electron transport chain then transfers the electrons to oxygen, which is the final electron acceptor in aerobic respiration. This process allows for the production of ATP, the energy currency of the cell.

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  • 23. 

    ATP is often an allosteric inhibitor of key enzymes in catabolic pathways. Which of the following statements in inconsistent with the role of ATP?

    • A.

      When ATP Levels are low in the cell, there is no inhibition of the catabolic pathway and ATP production is at a maximum

    • B.

      Increasing availability of ATP increases the energy available to drive endergonic reactions

    • C.

      When ATP levels are high in the cell, it is an indication that energy supply from catabolic reactions exceeds energy demand by anabolic reactions

    • D.

      The binding of ATP to allosteric sites on enzymes of the catabolic pathway decreases the production of ATP by the pathway.

    • E.

      ATP couples energy prodcution in catabolic pathways to energy demand in anabolic pathways.

    Correct Answer
    B. Increasing availability of ATP increases the energy available to drive endergonic reactions
    Explanation
    Increasing availability of ATP increases the energy available to drive endergonic reactions. This statement is inconsistent with the role of ATP because ATP is typically used as an energy source in endergonic reactions, not as a product that increases the energy available. In other words, ATP is broken down to release energy for endergonic reactions, rather than being produced to provide energy.

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  • 24. 

    Muscle cells in oxygen deprivation convert pyruvate to ________ and in this step gain

    • A.

      Lactate...ATP

    • B.

      Alcohol...ATP

    • C.

      Lactate...NAD+

    • D.

      Alcohol...CO2

    • E.

      ATP...NAD+

    Correct Answer
    C. Lactate...NAD+
    Explanation
    During oxygen deprivation, muscle cells undergo a process called anaerobic glycolysis. In this process, pyruvate is converted to lactate. This conversion allows the cells to continue producing ATP, the energy currency of the cell, in the absence of oxygen. Additionally, the conversion of pyruvate to lactate helps regenerate NAD+ molecules, which are necessary for glycolysis to continue. Therefore, the correct answer is lactate...NAD+.

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  • 25. 

    Which of the following is true regarding catabolic pathways?

    • A.

      They lead to the synthesis of catabolic compounds

    • B.

      They consume energy to build up polymers from monomers

    • C.

      They release energy as the degrade polymers to monomers

    • D.

      They do not depend on enzymes

    • E.

      Both A and B are correct

    Correct Answer
    C. They release energy as the degrade polymers to monomers
    Explanation
    Catabolic pathways involve the breakdown of larger molecules into smaller ones, such as polymers to monomers. This breakdown process releases energy, which can be used by the cell for various activities. Therefore, the statement "they release energy as they degrade polymers to monomers" accurately describes catabolic pathways.

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  • 26. 

    In an experiment studying photosynthesis performed during the day, you provide a plant with radioactive carbon (14C) dioxide as a metabolic tracer. The 14C is incorporated first into oxaloacetic acid. The plant is best characterized as a

    • A.

      C3 plant

    • B.

      CAM plant

    • C.

      Chemoautotroph

    • D.

      Heterotroph

    • E.

      C4 plant

    Correct Answer
    E. C4 plant
    Explanation
    A C4 plant is the best characterization for the given scenario because C4 plants have a specialized carbon fixation pathway that allows them to efficiently capture and use carbon dioxide, even in high temperatures and low carbon dioxide conditions. In these plants, the first product of carbon fixation is a four-carbon compound called oxaloacetic acid, which is consistent with the information provided in the question. This adaptation helps C4 plants to minimize water loss and maximize photosynthetic efficiency, making them well-suited for environments with intense sunlight and limited water availability.

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  • 27. 

    Phosphofructokinase is an important control enzyme. All of the following statements concerning this enzyme are true except:

    • A.

      It is activated by APM

    • B.

      It is activated by citrate

    • C.

      It is inhibited by ATP

    • D.

      It is a coordinator of the processes of glycolysis and the Krebs cycle

    • E.

      It is an allosteric enzyme

    Correct Answer
    B. It is activated by citrate
    Explanation
    Phosphofructokinase is an important control enzyme in glycolysis. It is activated by AMP, not APM. It is inhibited by ATP, which serves as a feedback mechanism to regulate the enzyme's activity. Phosphofructokinase is also an allosteric enzyme, meaning its activity can be modulated by binding of specific molecules. Additionally, it acts as a coordinator between glycolysis and the Krebs cycle, ensuring that the two processes are properly regulated and synchronized. However, it is not activated by citrate, making this statement false.

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  • 28. 

    An organism is discovered that consumes a considerable amount of sugar, yet does not gain much weight when denied air. Curiously, the consumption of sugar increases as air is removed from the organism's environment, but the organism seems to thrive even in the absence of air. When returned to normal air, the organism does fine. Which of the following best describes the organism?

    • A.

      It is a facultative anaerobe

    • B.

      It mus use a molecule other than oxygen to accept electrons from the electron transport chain

    • C.

      It is a normal eukaryotic organism

    • D.

      It is an anaerobic organism

    • E.

      The organism obviously lacks the Krebs cycle and the electron transport chain

    Correct Answer
    A. It is a facultative anaerobe
    Explanation
    The organism's ability to consume sugar and thrive in the absence of air suggests that it can switch between aerobic and anaerobic respiration. This is a characteristic of facultative anaerobes, which can use oxygen when available but can also survive without it by using alternative electron acceptors in the absence of oxygen. Therefore, the correct answer is that the organism is a facultative anaerobe.

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  • 29. 

    Which of the following is not considered to be a wear molecular interaction?

    • A.

      Covalent bond

    • B.

      Van der Waals interactions

    • C.

      Both A and C are correct

    • D.

      Hydrogen bond

    • E.

      Ionic bond in the presence of water

    Correct Answer
    A. Covalent bond
    Explanation
    Covalent bond is not considered to be a weak molecular interaction. Unlike hydrogen bonds, van der Waals interactions, and ionic bonds in the presence of water, covalent bonds involve the sharing of electrons between atoms, resulting in strong and stable bonds. Covalent bonds are formed when atoms have similar electronegativity and are held together by the sharing of electrons in their outermost energy levels. This type of bond is typically found in organic compounds and is responsible for the formation of molecules with specific shapes and properties.

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  • 30. 

    Collecting data based on observation is an example of ________; analyzing this data to reach a conclusion is an example of __________ reasoning.

    • A.

      Hypothesis-based science; inductive

    • B.

      Hypothesis-based science; deductive

    • C.

      Descriptive science; deductive

    • D.

      The process of science; deductive

    • E.

      Discovery science; inductive

    Correct Answer
    E. Discovery science; inductive
    Explanation
    Collecting data based on observation is a characteristic of discovery science, which involves making observations and gathering data to describe and understand natural phenomena. Analyzing this data to reach a conclusion is an example of inductive reasoning, which involves using specific observations to make generalizations or predictions. Inductive reasoning is commonly used in discovery science to draw conclusions based on the patterns or trends observed in the collected data. Therefore, the correct answer is "discovery science; inductive."

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  • 31. 

    What is the difference between covalent bonds and ionic bonds?

    • A.

      Covalent bonds involve the sharing of protons between atoms, and ionic bonds involve the sharing of neutrons between atoms.

    • B.

      Covalent bonds involve the sharing of protons between atoms, and iconic bonds involve the sharing of electrons between atoms.

    • C.

      Covalent bonds involve the transfer of electrons between atoms, and ionic bonds involve the sharing of neutrons between atoms.

    • D.

      Covalent bonds involve the sharing of neutrons between atoms, and ionic bonds involve the sharing of electrons between atoms.

    • E.

      Covalent bonds involve the sharing of electrons between atoms, and ionic bonds involve the electrical attraction between atoms.

    Correct Answer
    E. Covalent bonds involve the sharing of electrons between atoms, and ionic bonds involve the electrical attraction between atoms.
    Explanation
    Covalent bonds involve the sharing of electrons between atoms, which creates a strong bond between the atoms. Ionic bonds, on the other hand, involve the electrical attraction between atoms, where one atom donates electrons to another atom, creating a positive and negative charge. This attraction holds the atoms together.

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  • 32. 

    If atom 6x (atomic number 6) were allowed to react with hydrogen, the molecule formed would be

    • A.

      H-X-H I H

    • B.

      H I H-X-H I H

    • C.

      H-X-H

    • D.

      H=X=H

    • E.

      X-H

    Correct Answer
    B. H I H-X-H I H
  • 33. 

    All of the following statements are part of Charles Darwin's concept of natural selection except:

    • A.

      Most individuals in a species do not survive to reproduce

    • B.

      Every organism has the potential to produce more offspring than the local environment can support

    • C.

      Better adapted members of a species will survive and reproduce more successfully

    • D.

      Slight inheritable variations within a population may make an individual significantly more or less likely to survive in its environment, and thus to reproduce

    • E.

      Characteristics of organisms are inherited as genes on chromosomes

    Correct Answer
    E. Characteristics of organisms are inherited as genes on chromosomes
    Explanation
    Charles Darwin's concept of natural selection does include the statement that characteristics of organisms are inherited as genes on chromosomes. Natural selection is the process by which individuals with advantageous traits are more likely to survive and reproduce, passing on those traits to future generations. These traits are inherited through genes, which are located on chromosomes. Therefore, this statement is not part of the concept of natural selection.

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  • 34. 

    The atomic number of carbon is 6. 14C is heavier than 12C because the atomic nucleus of 14C contains

    • A.

      Seven protons and seven neutrons

    • B.

      Six protons and eight neutrons

    • C.

      Six protons and seven neutrons

    • D.

      Six protons and six neutrons

    • E.

      Eight protons and six neutrons

    Correct Answer
    B. Six protons and eight neutrons
    Explanation
    Carbon has an atomic number of 6, which means it has 6 protons in its nucleus. The atomic mass of an element is the sum of the number of protons and neutrons in its nucleus. Since 14C is heavier than 12C, it means that it has more neutrons. Therefore, the atomic nucleus of 14C contains 6 protons and 8 neutrons.

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  • 35. 

    The ionic bond of sodium chloride is formed when

    • A.

      Sodium and chlorine share an electron pair

    • B.

      Chlorine gains a proton from sodium

    • C.

      Sodium and chlorine both lose electrons from their outer valence shells

    • D.

      Sodium gains an electron from chlorine

    • E.

      Chlorine gains an electron from sodium

    Correct Answer
    E. Chlorine gains an electron from sodium
    Explanation
    In an ionic bond, one atom transfers an electron to another atom, resulting in the formation of ions with opposite charges. In the case of sodium chloride, sodium (Na) loses an electron and chlorine (Cl) gains that electron. This transfer of electron from sodium to chlorine allows chlorine to achieve a stable electron configuration with a full outer valence shell, while sodium becomes a positively charged ion. Therefore, the correct answer is "chlorine gains an electron from sodium".

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  • 36. 

    Evolution is biology's core theme that ties together all the other themes. This is because evolution

    • A.

      Explains the unity and diversity of life

    • B.

      Explains why some organisms have traits in common

    • C.

      Explains why distantly related organisms sometimes resemble each other

    • D.

      Explains how organisms become adapted to their environment through the differential reproductive success of varying individuals

    • E.

      All of the above

    Correct Answer
    E. All of the above
    Explanation
    Evolution is the correct answer because it encompasses all the given statements. It explains the unity and diversity of life by showing how different species share common ancestors and have evolved over time. It also explains why certain traits are present in multiple organisms, as these traits may have been advantageous and selected for through natural selection. Additionally, evolution accounts for the phenomenon of convergent evolution, where distantly related organisms develop similar traits due to similar environmental pressures. Lastly, evolution explains how organisms become adapted to their environment through the process of natural selection, where individuals with favorable traits are more likely to survive and reproduce.

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  • 37. 

    When blood glucose levels rise, the pancreas secretes insulin and as a result blood glucose levels decline. When blood glucose levels are low, the pancreas secretes glucagon and as a result blood glucose levels rise.Such regulation of blood glucose levels is an example of:

    • A.

      A feedforward mechanism

    • B.

      Positive feedback

    • C.

      Negative feedback

    • D.

      Feedback inhibition

    • E.

      Both C and D

    Correct Answer
    E. Both C and D
    Explanation
    The regulation of blood glucose levels by the pancreas secreting insulin when levels are high and glucagon when levels are low is an example of negative feedback. Negative feedback occurs when a change in a variable triggers a response that counteracts the initial change, bringing the variable back to its normal range. In this case, the secretion of insulin and glucagon helps to maintain blood glucose levels within a specific range. Feedback inhibition, which is also known as negative feedback, is a specific type of negative feedback where the end product of a process inhibits its own production. In this case, the high or low levels of blood glucose inhibit the secretion of insulin or glucagon, respectively.

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  • 38. 

    Which of these is a correct representation of the hierarchy of biological organization from least to most complex?

    • A.

      Organelle of an intestinal cell, digestive system, small intestine, large intestine, intestinal tissue, organism

    • B.

      Organelle of a stomach cell, digestive system, large intestine, small intestine, intestinal tissue, organism

    • C.

      Molecule, small intestine, large intestine, intestinal tissue, digestive system, organism

    • D.

      Molecule, digestive system, digestive cell organelle, small intestine, large intestine, intestinal cell, organism

    • E.

      Molecule, intestinal cell organelle, intestinal cell, intestinal tissue, digestive system, organism

    Correct Answer
    E. Molecule, intestinal cell organelle, intestinal cell, intestinal tissue, digestive system, organism
    Explanation
    This answer represents the hierarchy of biological organization from least to most complex. It starts with the molecule, which is the smallest unit of biological organization. Then, it progresses to the organelle of an intestinal cell, which is a subunit within the cell. Next, it moves to the intestinal cell itself, which is a single cell within the tissue. Then, it goes to the intestinal tissue, which is a group of cells working together. After that, it moves to the digestive system, which is a collection of organs involved in digestion. Finally, it ends with the organism, which is the highest level of biological organization.

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  • 39. 

    Who first names and described cells in 1665

    • A.

      Charles Darwin

    • B.

      Anton Van Leeuwenhoek

    • C.

      Robert Hooke

    • D.

      Theodor Schwann

    • E.

      Matthias Schleiden

    Correct Answer
    C. Robert Hooke
    Explanation
    Robert Hooke is the correct answer because he was the first person to name and describe cells in 1665. Hooke used a primitive microscope to observe thin slices of cork and noticed small compartments that he called "cells" due to their resemblance to small rooms or cells in a monastery. This discovery laid the foundation for the field of cell biology and was a significant contribution to our understanding of the microscopic world.

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  • 40. 

    Van der Waals interactions result when?

    • A.

      Electrons are not symmetrically distributed in a molecule

    • B.

      A hydrogen atoms loses an electron

    • C.

      Molecules held by ionic bond react with water

    • D.

      Hybrid orbitals overlap

    • E.

      Two polar covalent bonds react

    Correct Answer
    A. Electrons are not symmetrically distributed in a molecule
    Explanation
    Van der Waals interactions result when electrons are not symmetrically distributed in a molecule. These interactions occur due to temporary fluctuations in electron distribution, creating temporary positive and negative charges. These temporary charges induce a weak attraction between molecules, known as van der Waals forces. These forces are responsible for various phenomena, such as the ability of geckos to stick to surfaces and the condensation of gases into liquids.

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  • 41. 

    In a hypothetical world, every 50 years people over 6 feet tall are eliminated from the population. Based on your knowledge of natural selection, you would predict that the average height of the human population will

    • A.

      Gradually increase

    • B.

      Rapidly increase

    • C.

      Gradually decline

    • D.

      Remain unchanged

    • E.

      Rapidly decline

    Correct Answer
    C. Gradually decline
    Explanation
    In this hypothetical world, where people over 6 feet tall are eliminated every 50 years, natural selection would favor individuals who are shorter in height. Over time, the genes for shorter height would become more prevalent in the population, leading to a gradual decline in average height. This is because shorter individuals would have a higher chance of survival and reproduction, passing on their genes for shorter height to future generations.

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  • 42. 

    The dynamics of any ecosystem include the following major processes:

    • A.

      The flow of energy from sunlight to producers and then to consumers

    • B.

      The flow of energy from sunlight to producers and then to consumers, and the recycling of chemical nutrients

    • C.

      The flow of energy from sunlight to producers

    • D.

      The recycling of chemical nutrients

    • E.

      The flow of energy to producers and the recycling of nutrients

    Correct Answer
    B. The flow of energy from sunlight to producers and then to consumers, and the recycling of chemical nutrients
    Explanation
    The correct answer is the flow of energy from sunlight to producers and then to consumers, and the recycling of chemical nutrients. This answer encompasses two major processes that are essential for the dynamics of any ecosystem. The flow of energy from sunlight to producers and then to consumers represents the transfer of energy through the food chain, where producers (such as plants) convert sunlight into chemical energy through photosynthesis, and consumers obtain energy by consuming these producers. Additionally, the recycling of chemical nutrients refers to the continuous cycling of essential elements (such as carbon, nitrogen, and phosphorus) within the ecosystem, ensuring their availability for different organisms and maintaining the overall balance of the ecosystem.

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  • 43. 

    Why is it important that an experiment include a control group?

    • A.

      A control group assures that an experiment will be repeatable

    • B.

      The control group provides a reserve of experimental subjects

    • C.

      The control group is the group that the researcher is in control of; it is the group in which the researcher predetermines the nature of the results

    • D.

      Without the control group, there is no basis for knowing if a particular result is due to the variable being tested or to some other factor

    • E.

      A control group is required for the development of an "if...then" statement

    Correct Answer
    D. Without the control group, there is no basis for knowing if a particular result is due to the variable being tested or to some other factor
    Explanation
    Including a control group in an experiment is important because it allows researchers to compare the results of the experimental group to a group that is not exposed to the variable being tested. This helps to determine if any observed effects are actually caused by the variable being tested or if they are due to other factors. Without a control group, it would be impossible to confidently attribute any observed results to the variable being studied. Therefore, the presence of a control group provides a basis for evaluating the effectiveness or impact of the variable being tested.

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  • 44. 

    Which of the following best describes the relationship between the atoms described below?    Atom 1                    Atom 2        1                               3          H                              H        1                               1

    • A.

      They are ions

    • B.

      They are isomers

    • C.

      They are isotopes

    • D.

      They are polymers

    • E.

      They are both radioactive

    Correct Answer
    C. They are isotopes
    Explanation
    The relationship between Atom 1 and Atom 2 is that they are isotopes. Isotopes are atoms of the same element that have different numbers of neutrons in their nuclei. In this case, Atom 1 and Atom 2 have the same number of protons (1) and electrons (1), but they have a different number of neutrons (3 and 1 respectively). Therefore, they are isotopes of each other.

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  • 45. 

    Which of the following properties or processes do we associate with living things?

    • A.

      Energy processing

    • B.

      Growth and reproduction

    • C.

      Evolutionary adaptations

    • D.

      Responding to the environment

    • E.

      All of the above

    Correct Answer
    E. All of the above
    Explanation
    Living things are characterized by their ability to process energy, which is essential for their survival and functioning. They also exhibit growth and reproduction, allowing them to increase in size and produce offspring. Living organisms also possess evolutionary adaptations, which are changes over time that enhance their survival and reproductive success. Finally, living things can respond to their environment, adjusting their behavior or physiology in order to adapt and survive. Therefore, all of the listed properties and processes are associated with living things.

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  • 46. 

    Three or four of the following statements are true and correct. Which one, if any,is false?

    • A.

      The trace element iodine is required only in very small quantities by vertebrates

    • B.

      Iron is an example of an element needed by all organisms

    • C.

      Virtually all organisms require the same elements in the same quantities

    • D.

      Carbon, hydrogen, oxygen, and nitrogen make up approximately 96% of living matter

    • E.

      All of the statements are true and correct

    Correct Answer
    C. Virtually all organisms require the same elements in the same quantities
    Explanation
    The statement "Virtually all organisms require the same elements in the same quantities" is false. Different organisms have different elemental requirements and may require different quantities of certain elements.

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  • 47. 

    Which property of the carbon atom gives it compatibility with a greater number of different elements than any other type of atom?

    • A.

      Carbon has 6 to 8 neutrons

    • B.

      Carbon forms ionic bonds

    • C.

      Carbon has a valence of 4

    • D.

      A and C only

    • E.

      A, B, and C

    Correct Answer
    C. Carbon has a valence of 4
    Explanation
    The correct answer is that carbon has a valence of 4. Valence refers to the number of bonds that an atom can form with other atoms. Carbon has 4 valence electrons, which allows it to form strong covalent bonds with a variety of other elements. This property of carbon enables it to form complex and diverse organic compounds, making it compatible with a greater number of different elements than any other type of atom.

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  • 48. 

    Which of the following statements in completely correct?

    • A.

      NH3 is a weak base, and HCL is a strong acid

    • B.

      H2CO3 is a weak acid, and NaOH is a weak base

    • C.

      NH3 is a weak base, and H2CO3 is a strong acid

    • D.

      NH3 is a strong base, and HCL is a weak acid

    • E.

      H2CO3 is a strong acid, and NaOH is a strong base

    Correct Answer
    A. NH3 is a weak base, and HCL is a strong acid
    Explanation
    NH3 is a weak base because it only partially dissociates in water to form NH4+ and OH- ions. HCl is a strong acid because it completely dissociates in water to form H+ and Cl- ions.

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  • 49. 

    Humans can digest starch but not cellulose because

    • A.

      Humans have enzymes that can hydrolyze the alpha glycosidic linkages of starch but not the beta glycosidic linkages of cellulose

    • B.

      The monomer of starch is glucose, while the monomer of cellulose is galactose

    • C.

      Humans harbor starch-digesting bacteria in the digestive tract

    • D.

      Humans have enzymes that can hydrolyze the beta glycosidic linkages of starch but not the alpha glycosidic linkages of cellulose

    • E.

      The monomer of starch is glucose, while the monomer of cellulose is maltose

    Correct Answer
    A. Humans have enzymes that can hydrolyze the alpha glycosidic linkages of starch but not the beta glycosidic linkages of cellulose
    Explanation
    The correct answer is that humans have enzymes that can hydrolyze the alpha glycosidic linkages of starch but not the beta glycosidic linkages of cellulose. This is because the enzymes in the human digestive system, such as amylase, are specifically designed to break down the alpha glycosidic linkages found in starch. However, they do not possess the necessary enzymes to break down the beta glycosidic linkages present in cellulose. This is why humans can digest starch, which is a polysaccharide made up of glucose molecules, but cannot digest cellulose, which is also a polysaccharide but made up of glucose molecules linked by beta glycosidic linkages.

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  • 50. 

    Research suggests that side effects from Ritalin, the drug used to treat attention deficit disorder, may be caused by contamination of enantiomers, or molecules that

    • A.

      Differ in the electrical charge

    • B.

      Differ in the location of their double bonds

    • C.

      Lack an asymmetric carbon

    • D.

      Are mirror images of one another

    • E.

      Have identical three-dimensional shapes

    Correct Answer
    D. Are mirror images of one another
    Explanation
    The side effects from Ritalin may be caused by contamination of enantiomers, which are molecules that are mirror images of one another. This means that these molecules have the same chemical formula and connectivity, but they are not superimposable on each other. The presence of these mirror image molecules in the drug can lead to different biological effects and potentially cause side effects in patients.

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