Bio Connect Exam 2 Chapter 6: energy
Exergonic
A reaction is said to be ___ when it releases excess free energy and tends to proceed spontaneously.
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
Select all of the following that exhibit potential energy only
A stretched rubber band; water at the top of a dam; bow ready to fire an arrow; a boulder sitting at the top of a hill
All cells use a molecule ____ to carry and release energy cyclically. Select all that apply:
Adenosine triphosphate; ATP
In the following chemical reaction, which molecules is reduced? Ae + B ---> A + Be-
B
One __ is equal to the heat required to raise the temperature of one gram of water by one degree celsius.
Calorie
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
According to the equation for Gibbs free energy, the free energy (G) equals the ___ minus the product of the temperature and the ___ of the system.
Enthalpy; entropy
Second Law of Thermodynamics
Entropy increases, as potential energy is transformed into heat; disorder is more likely than order.
How does the amount of free energy input differ between exergonic and endergonic reactions?
Exergonic reactions proceed spontaneously and endergonic reactions require energy input.
Select all of the following that are forms of energy
electric current; mechanical energy; heat; light; sound
A reaction that requires an input of energy is said to be a(n) ___ reaction.
endergonic
All living things require which of the following, in order to carry out chemical reactions and thereby survive
energy
The first law of thermodynamics states the total amount of __ in the universe remains constant.
energy
Electrons carry ___, which is why the reduced form of a molecule has a __ energy level
energy; higher
What is the term used to describe the energy of a system that is available to do work?
free energy
During each energy conversion that happens in a living organism, some of the energy dissipates as .
heat
The word thermodynamics means ___ because all forms of energy can be converted into ___
heat changes; heat
Energy transformations can proceed spontaneously when disorder
increases
When a physical system becomes more disordered, the entropy
increases
Kinetic energy
is associated with movement
Potential energy
is stored with energy
Which are the two main states of energy
kinetic and potential energy
The energy associated with the motion of swinging a bat is a type of
kinetic energy
Most endergonic reactions in the cell require ___ energy than the amount released by the hydrolysis of ATP.
less
Most endergonic reactions in the cell require ___ energy than the amount releases by the hydrolysis of ATP
less
When the free energy changes that occurs as a result of a chemical reaction is ___ than zero, the reaction is spontaneous
less
Cells cannot ____, which is why heat cannot be used to do the work of cells
maintain a heat gradient
If ATP hydrolysis releases __ energy than an endergonic reaction consumes, the two reactions can be coupled and proceed spontaneously
more
In redox reactions, the ____ form of a molecule contains less energy because it has lost an energetic electron
oxidized
Chemical reactions can proceed in both directions (reactants to products or products to reactants). Reactions with a positive change in free energy favor the formation of the
reactants
Energy stored in the chemical bonds of a molecule cannot be harvested and used to make new bonds in a different molecule.
False
When a lion eats a giraffe, it both creates and adds new potential energy to its body
False
kinetic energy
Heat is a measure of the random motion of molecules, a form of :
Which are the following statements about the size and turnover rate of the ATP pool in a typical cell are true
Most cells have a few seconds supply of ATP; most cells have to produce more ATP constantly
Redox reaction is a term used to describe an __ reaction
Oxidation-reduction
The term oxidation comes from the fact ___ is the most common electron acceptor in biological systems.
Oxygen
Hydrolysis of which covalent bonds in ATP releases a considerable amount of energy?
Phosphate-phosphate bond
In chemical reactions, ___ refers to the process when one or more electrons are added to a molecule or atom?
Reduction
In a process known as __ , organisms obtain energy from the oxidation of organic molecules.
Respiration
With very few exceptions, all energy that enters biological systems ultimately comes from the __
Sun
what are the steps in the ATP cycle?
Synthesis of ATP using energy releases from exergonic reactions; hydrolysis of ATP to release energy that can be used to drive endergonic reactions
three components of ATP
a chain of 3 phophates; ribose; adenine
During photosynthesis, small inorganic molecules are combined into organic molecules using energy from
sunlight
Which of the ATP's phosphate bonds is hydrolyzed in most cellular reactions
the outermost
Even though energy dissipates as heat in biological systems, new energy flows into the biological world from
the sun
The term ____ describes energy changes, and two laws govern all energy changes in the universe
thermodynamics
Which of the following is true about spontaneous energy transformations
they proceed to convert matter from a more ordered to a less ordered form
Chemical potential energy stored in the molecules of living organisms can be converted into other forms, such as kinetic energy, light or electricity
true
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 molecules, which is thereby reduced.
Select the true statements about the ATP cycle in cells
ATP synthesis is an endergonic reaction; ATP hydrolysis is an exergonic reaction
energy that is the energy required to destabilize existing chemical bonds and initiate a chemical reaction
Activation
Select the products that result when the outermost phosphate group of ATP is hydrolyzed
ADP; energy; P1
Cell activities, such as biosynthesis, movement, and membrane transport, are powered by short-term supplies of
ATP
Cells use___ hydrolysis to drive endergonic reactions
ATP
Select the true statements about endergonic reactions.
Endergonic reactions are not spontaneous; endergonic reactions have a positive change in free energy; the products have a higher free energy than the reactants
All activities of living organisms involve changes in __, which is the ability to do work
Energy
In chemical reactions, the __ energy stored in the chemical bonds of a molecule can be used to make new bonds in a different molecule.
Energy
In photosynthesis, covalent bonds between atoms in sugar molecules store which of the following?
Energy
Living organisms can convert the potential energy stored in chemical bonds into what other forms of energy?
Kinetic; potential energy in the bonds of new molecules; electrical energy (electricity); light energy
Select the statements that describe the free energy (G) change of a spontaneous reaction.
The free energy of the products is less than the reactants; there is a negative free energy change
Select the reasons why the bonds between phosphates groups in ATP are easily broken:
The negatively charged phosphates repel each other; the phosphates are straining away from each other like a coiled spring; breaking the phosphate-phosphate bonds is a reaction with a low activation energy
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
Which of the following statements are correct about a reaction that is endergonic?
The products contain more energy than the reactants; the reaction requires an input of energy
First Law of Thermodynamics:
The total amount of energy in the universe remains constant; energy can change forms but cannot be destroyed
Which of the following statements about oxidized molecules is true?
They have less electrons and less energy than reduced molecules
The oxidized form of a molecule has less energy than its reduced form?
True
Name the type of energy that is a form of potential energy stored in chemical bonds
chemical
