Chapter 6

Question 1

activation energy

Answer 1

energy necessary for reactions to occur

Question 2

active site

Answer 2

enzyme’s specific region to which the substrate
binds

Question 3

allosteric inhibition

Answer 3

inhibition by a binding event at a site different from the active site, which induces a conformational change and reduces the enzyme’s affinity for its substrate

Question 4

anabolic

Answer 4

(also, anabolism) pathways that require an energy
input to synthesize complex molecules from simpler ones

Question 5

ATP

Answer 5

adenosine triphosphate, the cell’s energy currency

Question 6

bioenergetics

Answer 6

study of energy flowing through living systems

Question 7

catabolic

Answer 7

(also, catabolism) pathways in which complex
molecules break down into simpler ones

Question 8

chemical energy

Answer 8

potential energy in chemical bonds that
releases when those bonds are broken

Question 9

coenzyme

Answer 9

small organic molecule, such as a vitamin or its
derivative, which is required to enhance an enzyme’s
activity

Question 10

cofactor

Answer 10

inorganic ion, such as iron and magnesium ions,
required for optimal enzyme activity regulation

Question 11

competitive inhibition

Answer 11

type of inhibition in which the
inhibitor competes with the substrate molecule by binding to the enzyme’s active site

Question 12

denature

Answer 12

process that changes a substance’s natural properties

Question 13

endergonic

Answer 13

describes chemical reactions that require energy input

Question 14

enthalpy

Answer 14

a system’s total energy

Question 15

entropy (S)

Answer 15

measure of randomness or disorder within a system

Question 16

exergonic

Answer 16

describes chemical reactions that release free energy

Question 17

feedback inhibition

Answer 17

a product’s effect of a reaction
sequence to decrease its further production by inhibiting
the first enzyme’s activity in the pathway that produces it

Question 18

free energy

Answer 18

Gibbs free energy is the usable energy, or energy that is available to do work

Question 19

heat

Answer 19

energy transferred from one system to another that is
not work (energy of the molecules’ motion or particles)

Question 20

heat energy

Answer 20

total bond energy of reactants or products in a chemical reaction

Question 21

induced fit

Answer 21

dynamic fit between the enzyme and its substrate, in which both components modify their
structures to allow for ideal binding

Question 22

kinetic energy

Answer 22

energy type that takes place with objects or particles in motion

Question 23

metabolism

Answer 23

all the chemical reactions that take place inside cells, including anabolism and catabolism

Question 24

phosphoanhydride bond

Answer 24

bond that connects phosphates in
an ATP molecule

Question 25

potential energy

Answer 25

energy type that has the potential to do
work; stored energy

Question 26

substrate

Answer 26

molecule on which the enzyme acts

Question 27

thermodynamics

Answer 27

study of energy and energy transfer
involving physical matter

Question 28

transition state

Answer 28

high-energy, unstable state (an intermediate form between the substrate and the product) occurring during a chemical reaction

Question 29

Look at each of the processes, and decide whether it is endergonic or exergonic. In each case, does enthalpy increase or decrease, and does entropy increase or decrease?

Answer 29

1. Decay of a fertilizer heaps stays an exergonic Process.
2. Advancement of a child from an egg stays an endergonic Process.
3. Disturbance of sand workmanship stays an exergonic process.
4. Moving of a ball from slope to down stays an exergonic process.

Question 30

If no activation energy were required to break down sucrose (table sugar), would you be able to store it in a sugar bowl?

Answer 30

No. We can store chemical energy because of the need to overcome the barrier to its breakdown.

Question 31

One ATP molecule’s hydrolysis releases 7.3 kcal/mol of energy (ΔG = −7.3 kcal/mol of energy). If it takes 2.1 kcal/mol of energy to move one Na+ across the membrane (ΔG = +2.1 kcal/mol of energy), how many sodium ions could one ATP molecule’s hydrolysis move?

Answer 31

Three sodium ions could be moved by the hydrolysis of one ATP molecule. The ∆G of the coupled reaction must be negative. Movement of three sodium ions across the membrane will take 6.3 kcal of energy (2.1 kcal × 3 Na+ ions = 6.3 kcal). Hydrolysis of ATP provides 7.3 kcal of energy, more than enough to power this reaction. Movement of four sodium ions across the membrane, however, would require 8.4 kcal of energy, more than one ATP molecule can provide.

Question 32

Energy is stored long-term in the bonds of _____ and used short-term to perform work from a(n) _____ molecule.

Answer 32

glucose : ATP

Question 33

DNA replication involves unwinding two strands of parent DNA, copying each strand to synthesize complementary strands, and releasing the parent and daughter DNA. Which of the following accurately describes this process?

Answer 33

this is an anabolic process

Question 34

Consider a pendulum swinging. Which type(s) of energy is/are associated with the pendulum in the following instances: i. the moment at which it completes one cycle, just before it begins to fall back towards the other end, ii. the moment that it is in the middle between the two ends, iii. just before it reaches the end of one cycle (just before instant i.).

Answer 34

i. potential, ii. kinetic, iii. potential and kinetic

Question 35

Which of the following comparisons or contrasts between endergonic and exergonic reactions is false?

Answer 35

Endergonic reactions take place slowly and exergonic reactions take place quickly

Question 36

Which of the following is the best way to judge the relative activation energies between two given chemical reactions?

Answer 36

Compare their reaction rates

Question 37

Which of the following is not an example of an energy transformation?

Answer 37

Turning on a light switch

Question 38

In each of the three systems, determine the state of entropy (low or high) when comparing the first and second: i. the instant that a perfume bottle is sprayed compared with 30 seconds later, ii. an old 1950s car compared with a brand new car, and iii. a living cell compared with a dead cell.

Answer 38

i. low, ii. high, iii. low

i. The higher the entropy the more the system is disordered. The instant that a perfume bottle has sprayed the entropy is low compared with 30 seconds later because the system became less disordered

ii. As the disorder increases the entropy of the old car is higher than new car.

iii. Entropy is higher in living cells than dead cells because anabolic reactions take place in dead cells.

Question 39

The energy released by the hydrolysis of ATP is____

Answer 39

providing energy to coupled reactions.

Explanation for correct option

The energy delivered by the hydrolysis of ATP is lost as hotness. The remainder of the energy is used by cells to give energy to cell exercises.

ATP hydrolysis is an exergonic response. It is connected to other endergonic responses, allowing them to continue. In this way, hydrolysis of ATP provides power to related reactions.

Question 40

Which of the following molecules is likely to have the most potential energy?

Answer 40

Sucrose is likely to have the most potential energy. Therefore option ‘a’ is the correct answer.

Explanation

Energy is delivered when ATP is hydrolyzed. This energy is lost as hotness during the interaction and the remainder of the energy is used by cells to give energy to cell exercises. Glucose contains likely energy, however being a monosaccharide, it would have less expected energy than sucrose which is a disaccharide. ADP would use energy to join with an inorganic phosphate for the arrangement of ATP particles, which thus are utilized to control cell capacities. Accordingly, choices b, c, and d are the incorrect answers.

Question 41

Which of the following is not true about enzymes:

Answer 41

They increase ΔG of reactions.

Proteins don’t decide if a response is unconstrained (exergonic) or non-unconstrained (endergonic) because they don’t influence the free energy of the reactants and items. Accordingly, they don’t change the ΔG of a response.

Enzymes:
- They are usually made of amino acids.
- They lower the activation energy of chemical reactions.
- Each one is specific to the particular substrate(s) to
which it binds.

Question 42

An allosteric inhibitor does which of the following?

Answer 42

Binds to an enzyme away from the active site and changes the conformation of the active site, decreasing its affinity for the substrate.

An allosteric inhibitor binds to an enzyme away from the active site and changes the conformation of the active site, decreasing its affinity for the substrate.

Question 43

Which of the following analogies best describes the
induced-fit model of enzyme-substrate binding?

Answer 43

A hug between two people describes the induced-fit model of enzyme-substrate binding.

Question 44

Does physical exercise involve anabolic and/or catabolic
processes? Give evidence for your answer.

Answer 44

Anabolism and catabolism are the two general categories of biochemical reactions that construct up metabolism.

The physical exercises that increase muscle mass are anabolic methods.

Explanation

The physical exercises that raise muscle mass are anabolic methods.

Since the anabolic method is the formation of complex molecules from easier molecules by utilizing the energy from anabolic processes, it constructs up the organs and tissues by raising the differentiation of cells and eventually raising the muscle mass by synthesis of complex molecules. When somebody intakes hormones such as anabolic steroids, it facilitates protein synthesis and enhances muscle growth. Another example is the intake of leucine, a branched amino acid that makes new skeletal muscle proteins, and when this ensues on a large basis, the muscle mass is raised.

Question 45

Name two different cellular functions that require
energy that parallel human energy-requiring functions.

Answer 45

Cellular motion, as well as human motion are the two cellular functions that require energy.

Question 46

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

Answer 46

Spontaneous responses are responses that deliver free energy because of their negative change in free energy. Their reactants have a greater measure of put away energy than their outcomes. These responses happen over a long period.

Non-spontaneous responses or immediate ones are the exact inverses. In these responses, energy is assimilated, so there is no arrival of free energy. Along these lines, results of this sort of response have a great deal of free energy, in contrast to its reactants.

Question 47

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.

Answer 47

Regardless of the response is endergonic or exergonic, and their outputs are in a lower or higher state in correlation with both the reactants and the outcome, the progress condition of the response will be higher in energy than the reactants.

Explanation

It has been estimated that a change state emerges in a synthetic response which is among reactants and products. This change in particle shape is known as the activated state.

At the point when a change state emerges from low to high on an upward energy scale, the energy of reactants will be lesser. The energy of the reactant will continuously be lower than the progress state energy. The energy of the items will likewise be low as upward energy is going from low to high. This is noticed paying little heed to what sort of response is occurring that is, endergonic or exergonic.

Question 48

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?

Answer 48

The ant farm had lower entropy before the quake since they are profoundly coordinated inside their local area. After the earthquake, their framework had an increment in entropy since it became disarranged.

Whenever an earthquake happens nearby the ant farm, the passages, and paths will be obliterated. This will present turmoil and haphazardness in the profoundly requested arrangement of the ant farm. Accordingly, entropy will be higher in the event of a quake.

Before the earthquake, the ant farm is in profoundly requested style with passages and ways shaped through the sand. In light of its profoundly requested design, the problem is in the least and subsequently lower entropy would be noticed.

Question 49

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

Answer 49

In cooking, as food gets warming up in the stove, there is a critical loss of energy while arriving at the temperature and warming the air. Thus, entropy increase. While driving a vehicle, there is a lot of cycles that cause loss of energy. The greatest measure of energy goes with the consumption of fuel. The parts that encompass the motor hotness up and cause loss of energy also. Tires utilize an additional measure of energy because of friction. For this situation, entropy increments as well.

Explanation of first scenario

Whenever we cook food in the stove, we heat the food. In any case, the hotness which is presented isn’t constantly utilized completely to prepare the food. A portion of the energy gets lost and is moved into the encompassing air. This will coordinate entropy into the framework.

Explanation of Second scenario

Whenever we drive a vehicle, fuel is scorched to run the motor. Nonetheless, not all energy from the gas is utilized in the motor.

A portion of the energy is lost as hotness, which will warm up different parts of the vehicle. While the vehicle runs along with the
pavement, friction is caused between the tires and the pavement. This will create heat, which is again lost in the environmental elements. This expansion of energy into the other encompassing will build the entropy.

Question 50

Do you think that the EA for ATP hydrolysis is relatively
low or high? Explain your reasoning.

Answer 50

The activation energy for ATP is low since ATP is an entirely temperamental particle and it tends to be effortlessly transformed into ADP and Pi.

Explanation

ATP is a truly shaky atom, and it can without much of a stretch go through hydrolysis in the blink of an eye. This shows that ATP requires extremely low activation energy to actuate the response.

Question 51

With regard to enzymes, why are vitamins necessary for
good health? Give examples.

Answer 51

Vitamins are fundamental for great wellbeing since they are fundamental for the appropriate capacity of enzymes. For example, vitamin is a genuine necessity for good health.

Explanation: Vitamin is a coenzyme for a ton of catalysts that are answerable for the working of collagen. Alongside nutrients, a few inorganic particles represent cofactors in some critical responses. For example, vitamin C is a genuine illustration of the basics of our living being.

Question 52

Explain in your own words how enzyme feedback
inhibition benefits a cell.

Answer 52

Cells can control the number of metabolic products generated by using enzyme feedback inhibition. When there is too much of one product compared to the cell’s demands, feedback inhibition successfully induces the cell to reduce the synthesis of that product.

Benefits: The activity of an enzyme is regulated by the enzyme’s end product via a cellular regulation mechanism known as feedback inhibition. Cells can control how much of an enzyme’s end product is generated using this technique.

The majority of biochemical processes are multi-step and complex, requiring multiple enzymes to get from the starting substrate to the final product.

Enzyme feedback inhibition usually targets the pathway’s initial enzyme.