Biology > Chapter 8 > Flashcards

Chapter 8 Flashcards

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1
Q

Chemical reactions

A

Any process in which one or more substances (the reactants) are converted to one or more different substances (products)
-Involves the making and breaking of chemical bonds
- occurs when atoms have sufficient energy to combine or change their bonding partners

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2
Q

Law of conservation

A

Matter is conserved in a chemical reaction : reactions cannot create or destroy matter but can only rearrange it

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3
Q

Metabolism

A

The sum total of an organism’s chemical reactions, consisting of catabolic and anabolic pathways, which manage the material and energy resources of the organism
Elaborate road map of the thousands of chemical reactions that occur in a cell, arranged as interesting metabolic pathways

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4
Q

Metabolic pathway

A

A set of enzymatically controlled steps that begin with a specific molecule and results in the complete ion of a product or process in an organism
In such a sequence, each enzyme does a particular job and then leaves the succeeding task to the next enzyme
The product of one reaction because the reactant for the next

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5
Q

Energy

A

The capacity to do work; the capacity to bring about movement against an opposing force; the capacity for change

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6
Q

Potential energy

A

Energy stored in chemical bonds, as a concentration gradient or as an electric charge imbalance

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7
Q

Kinetic energy

A

The energy of motion; the type of energy that does work, that makes things change

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8
Q

To produce a change

A

Energy must transformed

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9
Q

Potential energy is energy matter possesses because…

A

Of its location, structure, or position

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10
Q

Molecules posses energy because….

A

Of the arrangement or position of electrons in the bond between their atoms

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11
Q

Chemical energy aka stored in bonds is a form of what

A

Potential energy available for release in a chemical reaction

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12
Q

The amount of potential energy of an electron is based on…

A

Its positions relative to other electrons and the protons is the nuclei of nearby atoms

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13
Q

Potential energy of a molecules depends on…

A

How it’s electrons are configured or positioned

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14
Q

If an electron is close to the negative charges on other electrons and far from the positive charges in nuclei, is has?

A

High potential energy

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15
Q

Forms of energy

A

Chemicals, electrical, heat, light, mechanical

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16
Q

The most convenient way of measuring energy

A

Heat

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17
Q

Energy changes in living systems resulting in…

A

Chemicals changes in which energy is stored, or released from, chemical bonds

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18
Q

Two types of metabolism

A

Anacolism and catabolism

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19
Q

Anabolism

A

Condensation reactions: link smaller molecules to form larger more complex molecules; require an input of energy; energy is captured in the chemical bonds that are formed/ this captured energy is stored in bonds as potential energy

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20
Q

An example of anabolic reactions

A

Glucose + fructose + energy — sucrose

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21
Q

Catabolism

A

Hydrolysis reactions; breaking down larger, more complex molecules into smaller ones, release the energy stored in the chemical bonds; released energy may be recaptured in new chemicals bonds, or used as kinetic energy

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22
Q

An example of catabolic reaction

A

Sucrose + water —- glucose + fructose + energy

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23
Q

Anabolic and catabolic reaction are considered

A

Coupled reactions

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24
Q

The laws of thermodynamics

A

Means “energy change” apply to all matter and energy transformations in the universe

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25
First law of thermodynamics
Energy is neither created nor destroyed, it is only transformed When energy is converted from one form to another, the total energy before and after the conversion is the same
26
Second law of thermodynamics
When energy is converted from one form to another, some of that energy becomes unavailable to do work No energy transformation is 100% efficient; some energy is lost to disorder; randomness due to thermal motion of particle (heat)
27
The quantity of energy is constant is…
1st Law
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Quality of energy is not is…
2nd law
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Chaos theory
If you don’t put energy into the system it will go into disorder
30
Entropy (S)
a measure of the smooth of disorder (randomness) in a system
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It take ____ to impose order on a system
Energy
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Unless energy is ___ to a system, it will be randomly arranged or disordered
Applied
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Spontaneous process is
Energetically favorable
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Definition of spontaneous process
A process that can occur with input of energy - simple diffusion is an example
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Products vs reactants in spontaneous process
Products have lower potential energy than the reactants; product molecules are more ordered than the reactant molecules
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Enthalpy (H)
Total energy = usable energy + unusable energy
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Free energy (G)
Usable energy that can do work; cell require it in chemical reactions
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Unusable energy (S)
Unusable energy - lost to disorder (heat)
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Triangle G or delta triangle (G) defined as
The overall change in free energy
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Delta G =
Gproducts - Greactants/ the different in free energy between the products and the reactants
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Delta G is negative?
Free energy is released Products = 5 reactants = 10 5 - 10 =-5
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Delta G is positive?
Input of free energy is required for reaction to occur Products = 10 reactants = 5 10-5=5
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What is the general rule when is come to chemical transformations?
If free energy is not available, a chemical reactions does not occur
44
Exergonic
Means “energy outward” Reactions release free energy (-deltaG)
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Exergonic reactions are ….
Spontaneous
46
Exergonic reactions are rolling what way up the hill?
Rolling down the hill.
47
Exergonic formula reactions are
Complex molecules — free energy + small molecules
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Endergonic
Means “energy inwards” Reactions that consume free energy (+deltaG)
49
Endergonic reactions are….
Non spontaneous
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Endergonic reactions roll what way up the hill?
They roll up the hill - energy required
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Endergonic formula reactions are…
Free energy + small molecules —— complex molecules
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ATP
Adenosine triphosphate
53
What does ATP contain?
Sugar ribose, the nitrogenous base adenine and a chain of three phosphate groups
54
When is energy released in ATP
When it is hydrolysis to ADP and Pi
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ADP
Adenosine Diphosphate
56
Pi
An organic phosphate. This is a phosphate ion free in solution.
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The hydrolysis of ATP
Is highly Exergonic. It releases a large amount of energy.
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Why does ATP have high potential energy?
Because of the four negative charges associated with the three adjacent phosphate group’s destabilizaes the molecules
59
ADP and Pi results after that hydrolysis of ATP
These molecule are more stable than ATP (they have less potential energy than ATP)
60
Energy coupling
Uses energy released from one reaction to power another reaction
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Energy barriers
Are between reactants and products control the rate of chemical reactions
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Most chemical reaction rates are too —— to result in the rapid changed needed for an organism to respond to the environment and to perform cellular functions
Slow
63
Why are barriers important? .
They block the tendency for a chemical run to occur that might allow for complex molecules to decompose spontaneously. They preset because temperatures are too low for reactants to have the elderly they need to complete these reactions.
64
Energy barriers must be broken to…
Carry out necessary life processes
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Reactants must reach a reactive mode called
The transition state, the bonds are destabilized
66
Activation energy
The energy needed to destabilize existing chemical bonds in the reactant and initiate a chemical reaction
67
Every chemical reactions between molecules involves
bonds breaking and bonds forming
68
How is an energy barrier to a chemical reaction overcame?
Increase the energy in the environment of the reacting molecules or lowering the activiation energy
69
Why is adding heat to the environment not the best option for overcoming energy barrier?
Reactiants will move faster, molecular collisions will increase. It will agitate the atoms in the molecules so the bonds with break but this speeds up all the reactions, not only those needed, heat can also denature proteins and kill cells
70
What allows for the activation energy to be lowered?
Add a catalyst, enable the reactants to reach the transition state even at moderate temperatures
71
Catalyst
Substance that speed up chemical reactions without being consumed or permanently altered Reduces the energy barrier that is preventing the chemicals reactions for proceeding Increases the rate of chemical reactions NO CATALYST MAKES A REACTION OCCUR THAT CANNOT OTHERWISE OCCUR
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Catalysis
The process of influencing chemical bond in a way that lower the activation energy need to initiate a chemical reaction Increase the rate of chemical reactions
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Most biological catalyst are proteins called —— that acts as a molecular framework in which chemical catalysis takes place
Enzymes
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What do enzymes do
The catalyze a reaction by lowering activation energy, enabling the reactant molecules to absorb enough energy to reach the transition state even at moderate temperatures
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Oxidorductases
Transfer electrons between molecules (energy metatbolism)
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Transferases
Transfer functions groups between molecules involves bonds
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Hydrolases
Add water to covalent bonds to break down molecules
79
Lyases
Catalyze nonhydrolytic bond breakage and aid in new bond forming
80
Isomerases
Move functional groups within a molecule (former isomer)
81
Ligases
Joins two molecules together
82
Active site
The region in an enzyme where catalysis occurs
83
Substrate
The reactant molecule that binds to an enzyme at the active site and participates in a chemical reaction Increase
84
Enzyme-substrate complex
Is held together by different types of bonds and electrical attractions
85
The enzyme may change while bound to the substrate….
But it will return to its original form when the reactions is complete
86
The —- of the enzyme determines its specificity
3-D shape FORM=FUNCTION
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Cofactors/coenzymes
Nonprotein helpers to help the enzyme functions normally, vitamins act as coenzymes
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During the formation of the enzyme substrate complex….
Chemical interactions occur that help to break old bonds and form new ones
90
An enzyme may use one or more mechanisms to catalyze a reactions
Orient substrates so they can react or induct strain by stretching the substrate
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Orient substrate so they can react
Specific atoms need to come together so bond can be formed
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Induce strain by stretching the substrate
Make bonds in the substrate unstable and more reactive
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Enzyme specificity depend on the precise
Interlocking of molecular shapes and interactions of chemical groups at the active site
94
Induced fit
Enzyme changed shape when it binds the substrate, this alter the shape of the active site
95
Enzyme catalysis can be considered a three step process what is it
Initiation, transition state facilitation, and termination
96
Initiation
Enzymes orient substrates precisely as they bind without the active site
97
Transition state facilitation
The act of binding induce the formation of the transition state, the interaction between the substrate and the R groups in the active site decreases the activation energy required for the reaction: more reactant molecules have sufficient kinetic energy to react this lowered activation energy
98
Termination
Run products have less affinity for the active site; binds ends; enzyme returns to original conformation; products are released
99
The biochemical reactions in cell operate within
Metabolic pathways in which the product of one reaction is a reactant for the next reaction
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Each metabolic pathway interact entenizivley and each reactions….
In each pathway is catalyzed by a specific enzyme
101
Enzyme inhibitors
Molecules the bind to the enzyme and slow reaction rates
102
Irreversible inhibition
Inhibition covalently bonds to side chains in the active site and permanently inactivated the enzyme
103
Reversible inhibition
Inhibitor bonds non covalently to the active site and prevents substrate from binding
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Competitive inhibitors
Competes with the natural substrate for bonding sites Degree of inhibition depends on concentration of substrate and inhibitors
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Uncompetitive inhibitors
Binds to the enzyme substrate complex, preventing release of products
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Noncompetitive inhibitors
Bind to the enzyme at a different site (not the active site)
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