## Critical Thinking Questions

28.
Describe the connection between anabolic and catabolic chemical reactions in a metabolic pathway.
1. Catabolic reactions produce energy and simpler compounds, whereas anabolic reactions involve the use of energy to make more complex compounds.
2. Catabolic reactions produce energy and complex compounds are formed, whereas in anabolic reactions free energy is utilized by complex compounds to make simpler molecules.
3. Catabolic reactions utilize energy and gives simpler compounds, whereas in anabolic reactions reactions, energy is produced and simpler compounds are used to make complex molecules.
4. Catabolic reactions produce energy and water molecules, whereas in anabolic reactions this free energy is utilized by simpler compounds to make only proteins and nucleic acids.
29.

Does physical exercise involve anabolic processes, catabolic processes, or both? Give evidence for your answer.

1. Physical exercise involves both catabolic and anabolic processes. Glucose is broken down into simpler compounds during physical activity. The simpler compounds are then used to provide energy to the muscles for contraction by the anabolic pathway.
2. Physical exercise is just a catabolic process. Glucose is broken down into simpler compounds during physical activity and the simpler compounds are then used to provide energy to the muscles for contraction.
3. Physical activity involves only anabolic processes. Glucose is broken down into simpler compounds during physical activity and the simpler compounds are then used to provide energy to the muscles for contraction by anabolic pathways.
4. Physical exercise involves both anabolic and catabolic processes. Cellulose is broken down into simpler compounds during physical activity. The simpler compounds are then used to provide energy to the muscles for contraction by anabolic pathways.
30.

How do chemical reactions play a role in energy transfer?

1. Energy from the breakdown of glucose and other molecules in animals is released as ATP, which transfer energy to other reactions.
2. Energy from the breakdown of glucose and other molecules in animals is released in the form of NADP, which transfer energy to other reactions.
3. Energy is released in the form of glucose from the breakdown of ATP molecules. These ATP molecules transfer energy from one reaction to other.
4. Energy is released in the form of water from the breakdown of glucose. These molecules transfer energy from one reaction to other.
31.

Name two different cellular functions that require energy.

1. Phagocytosis helps amoebae take up nutrients and pseudopodia help the amoebae move.
2. Phagocytosis allows amoebae to move and pseudopodia help in the uptake of nutrients.
3. Phagocytosis helps amoebae take up nutrients and cilia help amoebae move.
4. Phagocytosis helps amoebae in cell division and pseudopodia help amoebae move.
32.

Explain the conversion of energy that takes place when the sluice of a dam is opened.

1. Potential energy stored in the water held by the dam will convert to kinetic energy when it falls through the opening of the sluice.
2. Kinetic energy stored in the water held by the dam will convert to potential energy when it falls through the opening of the sluice.
3. Potential energy stored in the water held by the dam will convert to electrical energy when it falls through the opening of the sluice.
4. Hydrothermal energy stored in the water held by the dam will convert to kinetic energy when it falls through the opening of the sluice.
33.

Explain in your own words the difference between a spontaneous reaction and one that occurs instantaneously.

1. A spontaneous reaction is one which releases free energy and moves to a more stable state. Instantaneous reactions occur rapidly with sudden release of energy.
2. A spontaneous reaction is one which utilizes free energy and moves to a more stable state. Instantaneous reactions occur rapidly with sudden release of energy.
3. A spontaneous reaction is one which releases free energy and moves to a more stable state. Instantaneous reactions occur rapidly within a system by uptake of energy.
4. A spontaneous reaction is one which occurs rapidly with sudden release of energy. Instantaneous reactions release free energy and moves to a more stable state.
34.

Describe the position of the transition state on a vertical energy scale, from low to high, relative to the position of the reactants and products, for both endergonic and exergonic reactions.

1. The transition state of the reaction exists at a lower energy level than the reactants. Activation energy is always positive, regardless of whether the reaction is exergonic or endergonic.
2. The transition state of the reaction exists at a higher energy level than the reactants. Activation energy is always positive, regardless of whether the reaction is exergonic or endergonic.
3. The transition state of the reaction exists at a lower energy level than the reactants. Activation energy is always negative, regardless of whether the reaction is exergonic or endergonic.
4. The transition state of the reaction exists at an intermediate energy level than that of the reactants. Activation energy is always positive, regardless of whether the reaction is exergonic or endergonic.
35.

Imagine an elaborate ant farm with tunnels and passageways through the sand where ants live in a large community. Now imagine that an earthquake shook the ground and demolished the ant farm. In which of these two scenarios, before or after the earthquake, was the ant farm system in a state of higher or lower entropy? Why?

1. The ant farm is in the state of higher entropy after the earthquake, and energy must be spent to bring the system to low entropy.
2. The ant farm is in the state of lower entropy after the earthquake, and energy must be spent to bring the system to high entropy.
3. The ant farm is in the state of higher entropy before the earthquake, and energy is given out of the system after the earthquake.
4. The ant farm is in the state of lower entropy before the earthquake, and energy is given out of the system after the earthquake.
36.

Energy transfers take place constantly in every day activities. Think of two scenarios: cooking on a stove and driving. Explain how the second law of thermodynamics applies to these scenarios.

1. Heat is lost into the room while cooking and into the metal of the engine during gasoline combustion.
2. Heat gained while cooking helps to make the food and heat released due to gasoline combustion helps the car accelerate.
3. The energy given to the system remains constant during cooking, and more energy is added to the car engine when the gasoline combusts.
4. The energy given to the system for cooking helps to make food, and energy in the car engine remains conserved when gasoline combustion takes place.
37.
What does it mean for a system to be in a higher level of entropy? How can it be reduced?
1. Higher level of entropy refers to higher state of disorder in the system and it can be reduced by input of energy to lower the entropy.
2. Higher level of entropy refers to higher state of symmetry in the system and it can be reduced by release of energy to lower the entropy.
3. Higher level of entropy refers to low disorder in the system and it can be reduced by input of energy to increase the entropy.
4. Higher level of entropy refers to higher state of disorder in the system and it can be reduced by providing a catalyst to lower the entropy.
38.
When the air temperature drops and rain turns to snow, which law of thermodynamics is exhibited?
1. first law of thermodynamics
2. second law of thermodynamics
3. third law of thermodynamics
4. zeroth law of thermodynamics
39.
How does ATP supply energy to chemical reactions?
1. ATP dissociates and the energy released by breaking of a phosphate bond within ATP is used for phosphorylation of another molecule. ATP hydrolysis also provides energy to power coupling reactions.
2. ATP utilizes energy to power exergonic reactions by hydrolysis of ATP molecule. The free energy released as a result of ATP breakdown is used to carry out metabolism of products.
3. ATP utilizes energy to power endergonic reactions by dehydration of ATP molecule. The free energy released as a result of ATP breakdown is used to carry out metabolism of products.
4. ATP utilizes the energy released from the coupling reactions and that energy is used to power the endergonic and exergonic reactions.
40.
Is the $EA$ for ATP hydrolysis relatively low or high? Explain your reasoning.
1. $EA$ for ATP hydrolysis is low because considerable energy is released.
2. $EA$ for ATP hydrolysis is high because considerable energy is released.
3. $EA$ for ATP hydrolysis is intermediate because considerable energy is released.
4. $EA$ for ATP hydrolysis is high because a low amount of energy is released.
41.

What is phosphorylation as it occurs in chemical reactions?

1. the attachment of a phosphate to another molecule to facilitate a chemical reaction
2. the uptake of a phosphorous molecule by an ATP molecule to power chemical reactions
3. the release of a third phosphorous molecule of ATP during hydrolysis
4. the breakdown of a pyrophosphate molecule which gives phosphate ions
42.
If a chemical reaction could occur without an enzyme, why is it important to have one?
1. Enzymes are important because they give the desired products only from the reaction.
2. Enzymes are important because the products are obtained consistently with time.
3. Enzymes are important because they do not disturb the concentration of the products.
4. Enzymes are important because energy remains conserved and no loss of energy occurs.
43.
How does enzyme feedback inhibition benefit a cell?
1. Feedback inhibition benefits the cell by blocking the production of the products by changing the configuration of enzymes. This will prevent the cells from becoming toxic.
2. Feedback inhibition benefits the cell by blocking the production of the reactants by changing the configuration of enzymes. This will prevent the cells from becoming toxic.
3. Feedback inhibition benefits the cell by blocking the production of the products by changing the configuration of reactants. This will prevent the cells from becoming toxic.
4. Feedback inhibition benefits the cell by blocking the production of the products by reducing the reactants. This will prevent the cells from becoming toxic.
44.
What type of reaction allows chemicals to be available for an organism’s growth and maintenance in a timely manner?
1. enzymatically facilitated reactions
2. redox reactions
3. catabolic reactions
4. hydrolysis of ATP