Prepare For Biology Final Exam Quiz

1. An anabolic metabolic pathway is one that stores matter in complex biomolecules. This statement is:

True

Partially True

False

Not Enough Information

Anabolic metabolic pathways are responsible for building complex molecules from simpler ones, thus storing matter in complex biomolecules. Therefore, the statement is true.

Explanation

Anabolic metabolic pathways are responsible for building complex molecules from simpler ones, thus storing matter in complex biomolecules. Therefore, the statement is true.

2. During glycolysis 2 carbons from glucose are released as CO2.

False

True

Depends on the cell type

Partially true

During glycolysis, glucose is broken down into pyruvate without the release of CO2.

Explanation

During glycolysis, glucose is broken down into pyruvate without the release of CO2.

3. During the Krebs cycle (citric acid cycle) 4 carbons from glucose are released as CO2. This statement is:

Not applicable

Partially True

False

True

During the Krebs cycle, each pyruvate molecule (which came from glucose breakdown) loses a carbon in the form of carbon dioxide, creating a 2-carbon molecule called acetyl-CoA. Therefore, with two pyruvate molecules from one glucose molecule, a total of 4 carbons are released as CO2 during the cycle.

Explanation

During the Krebs cycle, each pyruvate molecule (which came from glucose breakdown) loses a carbon in the form of carbon dioxide, creating a 2-carbon molecule called acetyl-CoA. Therefore, with two pyruvate molecules from one glucose molecule, a total of 4 carbons are released as CO2 during the cycle.

4. If you add an allosteric activator of E1 to the cell, what will initially happen?

The E1 quaternary structure will change and the enzyme will become more active

The chemical species A will increase in concentration.

The enzyme will become less active due to the allosteric activator.

The enzyme will denature and become inactive.

When an allosteric activator binds to E1, it causes a conformational change in the enzyme's quaternary structure, leading to an increase in enzymatic activity. This is a common mechanism for regulating enzyme activity in cells.

Explanation

When an allosteric activator binds to E1, it causes a conformational change in the enzyme's quaternary structure, leading to an increase in enzymatic activity. This is a common mechanism for regulating enzyme activity in cells.

5. Nitrogen is an abundant element in biological macromolecules like ______________.

Water and Fiber

Carbohydrates and Lipids

Proteins and Nucleic acids

Vitamins and Minerals

Nitrogen is a key component of proteins due to its presence in amino acids. It is also found in nucleic acids such as DNA and RNA. Carbohydrates, lipids, vitamins, and minerals do not contain a significant amount of nitrogen compared to proteins and nucleic acids.

Explanation

Nitrogen is a key component of proteins due to its presence in amino acids. It is also found in nucleic acids such as DNA and RNA. Carbohydrates, lipids, vitamins, and minerals do not contain a significant amount of nitrogen compared to proteins and nucleic acids.

6. Curves A and B represent the same chemical reaction under two different conditions. Curve A represents an __________ reaction that is __________ by an enzyme.

Exothermic; uncatalyzed

Endergonic; catalyzed

Exergonic; uncatalyzed

Endothermic; catalyzed

In this scenario, 'exergonic' refers to a reaction that releases energy, while 'uncatalyzed' means the reaction occurs without the assistance of an enzyme.

Explanation

In this scenario, 'exergonic' refers to a reaction that releases energy, while 'uncatalyzed' means the reaction occurs without the assistance of an enzyme.

7. In the presence of an enzyme, a chemical reaction with ΔG = -10 kJ/mol and EA = 25 kJ/mol would result in _____ ΔG and _____ EA.

Still -10 kJ/mol; less than 25 kJ/mol

Less than -10 kJ/mol; greater than 25 kJ/mol

Greater than -10 kJ/mol; less than 25 kJ/mol

Greater than -10 kJ/mol; greater than 25 kJ/mol

When an enzyme is present, it can lower the activation energy (EA) required for a reaction to occur, but it does not affect the change in free energy (ΔG) of the reaction. Therefore, the correct answer is that ΔG remains at -10 kJ/mol while EA is reduced to less than 25 kJ/mol.

Explanation

When an enzyme is present, it can lower the activation energy (EA) required for a reaction to occur, but it does not affect the change in free energy (ΔG) of the reaction. Therefore, the correct answer is that ΔG remains at -10 kJ/mol while EA is reduced to less than 25 kJ/mol.

8. If you add a competitive inhibitor of enzyme E1 to a cell, which species would increase in concentration in the cell?

Species A and C

Species B and F

Species A and B

Species C and D

When a competitive inhibitor is added to enzyme E1, it competes with the substrate for the active site of the enzyme. This results in an increase in concentrations of Species A and B as the inhibitor prevents the substrate from binding and being converted to the respective products.

Explanation

When a competitive inhibitor is added to enzyme E1, it competes with the substrate for the active site of the enzyme. This results in an increase in concentrations of Species A and B as the inhibitor prevents the substrate from binding and being converted to the respective products.

9. During the turnover of an enzyme, all of the following events occur EXCEPT:

The enzyme denatures under high temperature

The products are bound so tight that the enzyme is unable to release them

The substrate binds to the active site of the enzyme

The enzyme undergoes conformational changes

During the turnover of an enzyme, various events occur such as substrate binding, conformational changes in the enzyme to facilitate catalysis, and release of products. The incorrect answers provided do not accurately represent an event that should be excluded from the turnover process.

Explanation

During the turnover of an enzyme, various events occur such as substrate binding, conformational changes in the enzyme to facilitate catalysis, and release of products. The incorrect answers provided do not accurately represent an event that should be excluded from the turnover process.

10. In the presence of an enzyme a chemical reaction has a ΔG of -13 kJ/mol and a EA of +5 kJ/mol. This reaction is endergonic. This statement is:

True

Partially true

False

Cannot be determined

The correct answer is false because even though the ΔG is negative, indicating a spontaneous reaction, the fact that the EA (activation energy) is positive makes the overall reaction endergonic, requiring energy input. The presence of an enzyme can lower the EA but does not change the overall endergonic nature of the reaction.

Explanation

The correct answer is false because even though the ΔG is negative, indicating a spontaneous reaction, the fact that the EA (activation energy) is positive makes the overall reaction endergonic, requiring energy input. The presence of an enzyme can lower the EA but does not change the overall endergonic nature of the reaction.

11. An electron far away from the nucleus will _____ potential energy and _______ kinetic energy as it moves away from the nucleus.

Decrease; gain

Maintain; increase

Gain; lose

Loss; decrease

When an electron moves away from the nucleus, it gains potential energy due to the increase in distance from the attractive force of the nucleus. As a result, it loses kinetic energy since it is moving against the attractive force of the nucleus.

Explanation

When an electron moves away from the nucleus, it gains potential energy due to the increase in distance from the attractive force of the nucleus. As a result, it loses kinetic energy since it is moving against the attractive force of the nucleus.

12. During the process of glycolysis, where do the net 2 ATP come from?

Photosynthesis

Krebs cycle

Substrate-level phosphorylation of ADP

Electron transport chain

During glycolysis, ATP is generated through substrate-level phosphorylation of ADP, not through the electron transport chain, Krebs cycle, or photosynthesis.

Explanation

During glycolysis, ATP is generated through substrate-level phosphorylation of ADP, not through the electron transport chain, Krebs cycle, or photosynthesis.

13. In the presence of an enzyme, a chemical reaction with a ΔG of -13 kJ/mol and an EA of +5 kJ/mol is non-spontaneous. This statement is:

Partially true

Cannot be determined

False

True

The statement is false because when the ΔG value is negative, it indicates that the reaction is spontaneous. The activation energy (EA) is the energy required to start a reaction, but does not determine spontaneity.

Explanation

The statement is false because when the ΔG value is negative, it indicates that the reaction is spontaneous. The activation energy (EA) is the energy required to start a reaction, but does not determine spontaneity.

14. Fats have the highest energy density (calories per gram) of all nutritional sources. This is because they are rich in which type of bonds?

N - H

S - H

O - H

C - H

Fats have the highest energy density due to the high number of C - H bonds which store a significant amount of energy.

Explanation

Fats have the highest energy density due to the high number of C - H bonds which store a significant amount of energy.

15. The enzyme phosphofructokinase is a key control point for glycolysis and is regulated by both ATP and AMP. ATP is an allosteric activator of phosphofructokinase. This statement is:

False

True

Partially true

Can't be determined

Phosphofructokinase is actually inhibited by ATP and activated by AMP, making the statement false.

Explanation

Phosphofructokinase is actually inhibited by ATP and activated by AMP, making the statement false.

16. The enzyme phosphofructokinase is a key control point for glycolysis and is regulated by both ATP and AMP. AMP is an allosteric activator of phosphofructokinase. This statement is:

False

True

Not relevant

Partially true

Phosphofructokinase is indeed a key control point in glycolysis, and AMP acts as an allosteric activator of this enzyme, making the statement true.

Explanation

Phosphofructokinase is indeed a key control point in glycolysis, and AMP acts as an allosteric activator of this enzyme, making the statement true.

17. What is the major difference between starch and cellulose?

Cellulose is digestible by humans, while starch is not.

Both starch and cellulose have the same chemical structure.

The glycosidic linkages are different so one has a helical structure and the other a fiberous structure

Starch is found in animal cells while cellulose is found in plant cells.

Starch and cellulose have different glycosidic linkages which result in their distinct structural differences. While starch is helical and mainly used for energy storage, cellulose has a fibrous structure providing structural support in plant cells.

Explanation

Starch and cellulose have different glycosidic linkages which result in their distinct structural differences. While starch is helical and mainly used for energy storage, cellulose has a fibrous structure providing structural support in plant cells.

18. An anabolic metabolic pathway is one that stores energy in compounds with high energy bonds. This statement is:

Partially true

Uncertain

False

True

Anabolic metabolic pathways are responsible for building complex molecules from simpler ones, which requires the input of energy. This energy is stored in compounds with high energy bonds, making the statement true.

Explanation

Anabolic metabolic pathways are responsible for building complex molecules from simpler ones, which requires the input of energy. This energy is stored in compounds with high energy bonds, making the statement true.

19. During the conversion of glucose and oxygen into carbon dioxide and water in the cell, which of the following pathways DO NOT create NADH?

Fermentation

Krebs Cycle

Glycolysis

Oxidative Phosphorylation

Oxidative Phosphorylation is the stage in cellular respiration where NADH is used to create ATP, rather than being produced.

Explanation

Oxidative Phosphorylation is the stage in cellular respiration where NADH is used to create ATP, rather than being produced.

20. What is the primary role of molecular oxygen (O2) during cellular respiration?

Provide energy directly to the cell as ATP

Act as an acceptor for electrons and hydrogen to form water in mitochondria

Release carbon dioxide as a byproduct of the Krebs cycle

Help break down glucose into pyruvate in the cytoplasm

During cellular respiration, molecular oxygen acts as an acceptor for electrons and hydrogen to form water in the mitochondria, playing a critical role in the electron transport chain and ATP production.

Explanation

During cellular respiration, molecular oxygen acts as an acceptor for electrons and hydrogen to form water in the mitochondria, playing a critical role in the electron transport chain and ATP production.

21. Which chemical reaction is involved in the release of energy in the cell to power biological processes?

The hydrolysis of ATP to form ADP and Pi

The breakdown of carbohydrates to form ATP.

The binding of ATP to enzymes for activation.

The synthesis of ATP from ADP and Pi.

22. In the presence of an enzyme a chemical reaction has a ΔG of -13 kJ/mol and a EA of +5 kJ/mol. This reaction is non-spontaneous. This statement is:

True

False

Partially True

Cannot be Determined

The given question states that the reaction has a negative ΔG (-13 kJ/mol) and a positive EA (+5 kJ/mol), which means that the reaction is actually spontaneous, contrary to the initial statement of it being non-spontaneous.

Explanation

The given question states that the reaction has a negative ΔG (-13 kJ/mol) and a positive EA (+5 kJ/mol), which means that the reaction is actually spontaneous, contrary to the initial statement of it being non-spontaneous.