Question 1

In many organelles, groups of different enzymes are located on membranes in close proximity to each other because

Accepted Answer

Enzymes located on membranes in close proximity to each other are usually part of the same metabolic pathway. Keeping them closer together increases the efficiency of the pathway by allowing for faster and more efficient transfer of intermediates between enzymes, reducing the chance that intermediates will diffuse away or react with other molecules. This process is known as metabolic channeling.

Question 2

Almost all the chemical reactions that occur in cells are catalyzed by ____________________ .

Accepted Answer

The answer of Almost all the chemical reactions that occur...

Question 3

Physiologists monitored metabolite concentrations generated during exercise in three groups of individuals (those with poor fitness, average fitness, and exceptional fitness); which statement best summarizes their findings?

Accepted Answer

The statement best summarizing the findings of the study is that exercise produced an almost immediate positive metabolic effect in which the strength and duration was proportional to the fitness level; exercise was beneficial to all participants. This indicates that even individuals with poor fitness can benefit from exercise, but the level and duration of benefits may be less compared to those with better fitness. The study does not suggest that exercise benefits conclude immediately upon cessation or that unfit individuals are unlikely to experience benefits from exercise for at least 30 days after starting an exercise program. Additionally, the study does not show that metabolites extracted from the blood of unfit individuals suppress the level of metabolism of cells growing in tissue culture.

Question 4

The gain of electrons by one atom from another atom is referred to as ____________________.

Accepted Answer

The answer of The gain of electrons by one atom...

Question 5

When chemical energy is converted into kinetic energy in a biological system, ____________________ [more than all, less than all, or all] of the available energy is converted.

Accepted Answer

The answer of When chemical energy is converted into kinetic...

Question 6

The capture and use of energy by living organisms involves numerous chemical reactions. Collectively these processes are known as ____________________.

Accepted Answer

The answer of The capture and use of energy by...

Question 7

The energy input needed to start a chemical reaction is the ____________________ energy.

Accepted Answer

The answer of The energy input needed to start a...

Question 8

A rotted log indicates that the ____________________ law of thermodynamics has been operating.

Accepted Answer

The answer of A rotted log indicates that the ____________________...

Question 9

If provided with the proper conditions, enzymes recovered from living tissues can be used in cell-free industrial processes; for example,

Accepted Answer

All three examples provided involve the use of enzymes recovered from living tissues in cell-free industrial processes. Amylases, lipases, and proteases improve the function of detergents, cellulases and pectinases clarify fruit juice, and proteases in pineapple and papaya can tenderize meat. Therefore, choice D is the best answer.

Question 10

A catalyst affects the ____________________ at which a chemical reaction occurs, but it is not itself changed during the reaction.

Accepted Answer

The answer of A catalyst affects the ____________________ at which...

Question 11

A calorie represents the

Accepted Answer

A calorie is a unit of measurement for energy, specifically the amount of energy needed to raise the temperature of one gram of water by one degree Celsius. It is commonly used to measure the energy content of food. One calorie is equivalent to 4.184 joules.

Question 12

Carbon dioxide is one product of the metabolic process called ____________________ that occurs in both plants and animals.

Accepted Answer

The answer of Carbon dioxide is one product of the...

Question 13

Which of the following strategies is not used by cells to help enzymes and substrates find each other?

Accepted Answer

While enzymes do require a certain amount of kinetic energy to function, producing heat to increase the frequency of molecular collisions is not a strategy used to help enzymes and substrates find each other. The other choices are all examples of strategies used by cells to bring enzymes and substrates together.

Question 14

The image below diagrams the action of an enzyme. 
Notice that the enzyme is depicted as being more tightly wrapped around the substrates in step 2 than it is in step 1. Why is this?

Accepted Answer

When a substrate binds to the active site of an enzyme, the enzyme changes its shape to better fit around the substrate, leading to a tighter fit. This change in shape is known as induced fit and is crucial for the reaction to proceed efficiently.

Question 15

In the figure below, E1, E2, and E3 represent three enzymes in the membrane of a mitochondrion. 
Which of the following is true?

Accepted Answer

The answer of In the figure below, E1, E2, and...

Question 16

The sequential reaction pathway A → B → C → D is dependent on enzymes for each separate step. How many different enzymes would be required to produce D if starting with A?

Accepted Answer

Since each separate step requires its own enzyme, there would be a total of three enzymes required to produce D starting with A.

Question 17

A molecule of methane burns, producing carbon dioxide, heat, light, and water. The direction of the event is dictated by the ____________________ law of thermodynamics.

Accepted Answer

The answer of A molecule of methane burns, producing carbon...

Question 18

Comparative studies have repeatedly shown that smaller animals have faster metabolic rates than larger animals, yet human males are both larger and have a higher average BMR than human females. What explains the variation in the pattern?

Accepted Answer

The metabolic rates of different tissues vary; the male body consists of a high percentage of energy-consuming muscle. This explains why even though human males are larger, they have a higher BMR than females. Muscle tissue has a higher metabolic rate than other tissues, such as fat, and since males have a higher percentage of muscle, their overall BMR is higher.

Question 19

The application of modern biological research methods have shown that the most successful strategy for permanent weight loss almost always involves

Accepted Answer

The answer of The application of modern biological research methods...

Question 20

Catabolic reactions are tightly coupled to ____________________ reactions that require energy.

Accepted Answer

The answer of Catabolic reactions are tightly coupled to ____________________...

Quiz 8: Energy, Metabolism, and Enzymes