Biology 181 - Chapter 6

How much energy is released when the outermost phosphate bond of ATP is hydrolyzed under standard conditions?

7.3 kcal/mol

An organic molecule has 10 C-H bonds. The full oxidation of all the C-H bonds in this molecule would yield _____ kcal per mole.

988

From the list below, select the three components of ATP.

A chain of three phosphates Ribose Adenine

What is entropy?

A measure of the amount of disorder in a system

Which of the following statements about chemical reactions are true?

A reaction that is exergonic in the forward direction will be endergonic in the reverse direction. Chemical reactions are reversible.

Which nitrogenous base is a component of ATP?

Adenine

In the following chemical reaction, which molecule(s) is(are) reduced? Ae- + B --> A + Be-

B

__________ energy is associated with movement, while _________ energy is stored energy.

Blank 1: Kinetic Blank 2: Potential

The Blank 1Blank 1 activation , Correct Unavailable Blank 2Blank 2 energy , Correct Unavailable for an exergonic reaction is lower in the presence of a catalyst for the reaction.

Blank 1: activation Blank 2: energy

In broad terms, energy can exist in two states: ________ energy and _________ energy.

Blank 1: potential Blank 2: kinetic

If you stretch a rubber band, you will give it energy; and when the rubber band is released, it has energy when it flies through the air.

Blank 1: potential, elastic, or elastic potential Blank 2: kinetic

Select the ways that catalysis affects chemical reactions.

Catalysts accelerate both the forward and reverse reactions by the same amount. Catalysts reduce activation energy.

The activation energy is a barrier to the formation of products. How can this be overcome?

Catalysts can be used to lower the activation energy.

Why do catalysts increase the rate of a chemical reaction?

Catalysts stabilize the transition state in a reaction.

______ energy is a form of potential energy stored within the covalent bonds of molecules.

Chemical

According to the equation for Gibbs free energy, the free energy (G) equals the Blank 1Blank 1 heat , Incorrect Unavailable minus the product of the temperature and the Blank 2Blank 2 disorder , Incorrect Unavailable of the system (to receive credit, you must spell out terms completely for the fill-in blanks).

Enthalpy Entropy

Which of the following is another way to state the second law of thermodynamics?

Entropy increases.

How does the change in free energy differ between exergonic and endergonic reactions?

Exergonic reactions have a negative change in free energy whereas endergonic reactions have a positive change in free energy.

In photosynthesis, energy absorbed from sunlight is used to

combine small inorganic molecules into larger organic molecules

Living organisms can convert the potential energy stored in chemical bonds into what other forms of energy?

electrical energy (electricity) light energy kinetic energy potential energy in the bonds of new molecules

During the breakdown of small organic molecules, oxidation occurs when

electrons are removed from an atom or molecule.

A reaction that requires an input of energy is said to be a(n)

endergonic

A reaction that requires an input of energy is said to be a(n) _______ reaction.

endergonic, non-spontaneous, or not spontaneous

Work in the cell or in the physical world can only be done with expenditure of ; it is defined as the capacity to do work.

energy

Work in the cell or in the physical world can only be done with expenditure of _________; it is defined as the capacity to do work.

energy

___________ stored in the chemical bonds of a molecule can be used to make new bonds in a different molecule.

energy

During each energy conversion that happens in a living organism, some of the energy dissipates as .

heat

When a physical system becomes more disordered, the entropy

increases

In general, energy transformations can proceed spontaneously when disorder

increases or is increased

Heat is a measure of the random motion of molecules, a form of _______ energy.

kinetic

Fats are useful as energy storage molecules because they contain

many C-H bonds.

Heat is a measure of the random Blank 1Blank 1 motion , Correct Unavailable of molecules.

motion

Redox reaction is a term used to describe an _________- __________ reaction.

oxidation-reduction

A fraction of the energy from the Sun is captured by plants, algae, and some bacteria through the process of Blank 1Blank 1 photosynthesis , Correct Unavailable.

photosynthesis

Green plants, certain bacteria, and algae can all perform the process of Blank 1Blank 1 photosynthesis , Correct Unavailable during which the energy of light is used to synthesize

photosynthesis

As living organisms consume other living organisms,

potential energy is transferred from one organism to another.

True or false: ATP hydrolysis has a positive ΔG.

False

True or false: Energy stored in the chemical bonds of a molecule cannot be harvested and used to make new bonds in a different molecule.

False

True or false: The bonds between phosphates in ATP are very difficult to hydrolyze.

False

True or false: When a lion eats a giraffe, it both creates and adds new potential energy to its body.

False

True or false: When an electron is added to a molecule, the molecule is oxidized.

False

The energy available to do work in a system is called_________ energy.

Free

What is the term used to describe the energy of a system that is available to do work?

Free energy

Which of the following equations represents the correct relationship between free energy (G), entropy (S), temperature (T), and enthalpy (H)?

G = H - TS

Energy is usually measured as which of the following?

Heat

Select two ways to increase the rate of reactions.

Lower the activation energy Increase energy of reactants

During a chemical reaction, which molecules become oxidized?

Molecules that have an electron removed

During a chemical reaction which molecules become reduced?

Molecules that have one or more electrons added

The amount of heat required to raise the temperature of one gram of water by one degree Celsius equals which of the following?

One calorie

Which line indicates that a catalyst is lowering the activation energy of the reaction?

Red line

When you consider the second law of thermodynamics, which of the following is more likely to occur?

Soda fizzes A column of bricks tumbles over Ice melts

During photosynthesis, small inorganic molecules are combined into organic molecules using energy from

Sunlight

The energy that flows through biological systems on Earth ultimately comes from which source?

The Sun

Select the true statements about endergonic reactions.

- Endergonic reactions have a positive change in free energy. - Endergonic reactions are not spontaneous. - The products have a higher free energy than the reactants.

Select the statements that describe the free energy (G) change of a spontaneous reaction.

- There is a negative free energy change. - The free energy of the products is less than the reactants.

The rate of an exergonic reaction can be increased by lowering the _____________ energy required to destabilize chemical bonds in the reactants.

activation

In order to be initiated, all chemical reactions, even exergonic ones, need

activation energy

________ __________ is the energy required to destabilize existing chemical bonds and initiate a chemical reaction.

activation energy

In chemical reactions, refers to the process when one or more electrons are added to a molecule or atom.

reduction

Chemical reactions are ___________, which means that they can proceed in either direction (reactants to products or products to reactants).

reversible

When the free energy change that occurs as a result of a chemical reaction is Blank 1Blank 1 greater , Incorrect Unavailable than zero, the reaction is spontaneous.

smaller

When the free energy change that occurs as a result of a chemical reaction is than zero, the reaction is spontaneous.

smaller

With very few exceptions, all energy that enters biological systems ultimately comes from the .

sun

Phosphate bonds in ATP are high energy bonds, because they are

unstable.

According to the equation ΔG = ΔH - T ΔS, which factor determines whether a reaction is spontaneous?

ΔG

What equation is used to evaluate whether a chemical reaction is spontaneous?

ΔG = ΔH - TΔS

What is an example of an object with high potential energy?

Water stored in a reservoir behind a dam

What occurs during a redox reaction?

When an atom or molecule is oxidized, the electron that is removed is transferred to another atom or molecule, which is thereby reduced.

In a chemical reaction, an electron is transferred from molecule X to molecule Y. Which of the two molecules is oxidized in this reaction?

X

All cells use a molecule called Blank 1Blank 1 ATP , Correct Unavailable to carry and release energy cyclically.

ATP

What molecule is a common energy source for living organisms?

ATP

Which statement about energy conversion is true?

During any type of energy conversion, some of the energy is lost into the environment as heat.

All living things require which of the following, in order to carry out chemical reactions and thereby survive?

Energy

What is the term for the ability to do work?

Energy

What are the two main states of energy?

Kinetic energy and potential energy

Which of the following describes the major difference between kinetic and potential energy?

Kinetic energy is the energy of motion and potential energy is associated with the position of an object.

What causes the rate of some chemical reactions to be very slow?

Large activation energy

What is the first law of thermodynamics?

The first law states that energy cannot be created or destroyed.

Select all of the following that can occur during the reduction of an atom or molecule.

The net charge of the atom or molecule decreases due to addition of negatively charged electron(s). One or more electrons are added to the atom or molecule.

Why can cells use ATP or ADP hydrolysis to release energy but not AMP?

The phosphate in AMP is not attached by a high energy bond.

Select all of the following that exhibit potential energy only.

Water at the top of a dam Bow ready to fire an arrow A boulder sitting at the top of a hill A stretched rubber band

Which characteristic of ATP is responsible for its high energy?

The repulsion of the negative phosphate groups

What is the second law of thermodynamics?

The second law states that transformation of energy from one form to another increases entropy.

Which of the following is the branch of chemistry concerned with energy changes?

Thermodynamics

Which of the following statements about oxidized molecules is true?

They have fewer electrons and less energy than reduced molecules.

Which of the following is true about spontaneous energy transformations?

They proceed to convert matter from a more ordered to a less ordered form.

True or false: Chemical potential energy stored in the molecules of living organisms can be converted into other forms, such as kinetic energy, light or electricity.

True

True or false: Heat energy cannot be used by cells to do work.

True

True or false: The energy associated with swinging a bat is a type of kinetic energy.

True

True or false: The oxidized form of a molecule has less energy than its reduced form.

True

True or false: Thermodynamics is the study of energy changes in the Universe.

True

One Blank 1Blank 1 calorie , Correct Unavailable is equal to the heat required to raise the temperature of one gram of water by one degree Celsius. In order to receive credit, you must spell the word (no abbreviations).

calorie

The process of influencing chemical bonds to lower the activation energy of a reaction is called

catalysis

Any agent that speeds up the rate of a chemical reaction without being permanently changed or consumed by it is known as a(n) .

catalyst

Name the type of energy that is a form of potential energy stored in chemical bonds.

chemical

Because cells are too small to maintain significant internal temperature differences, cells rely on Blank 1Blank 1 chemical , Correct Unavailable reactions rather than a Blank 2Blank 2 chemical , Incorrect Unavailable gradient to do work.

chemical temperature, heat, or thermal