Quiz 2 Flashcards
(180 cards)
1
Q
Is heat flow a source of energy
A
no
2
Q
What is Gibbs Free energy
A
stored energy that can be measured
3
Q
What does Gibbs Free energy express
A
the amount of energy capable of doing work in a reaction
4
Q
What are the requirements for standard transformed conditions
A
25C
1atm
1M of reactants and products
ph 7.0
5
Q
What is the formula for pH calculation
A
ph=-log[H+]
6
Q
Are there exceptions to 1 M concentrations for standards
A
yes
7
Q
What are the exceptions to 1M concentrations for standards
A
H+
H2O
Mg2+
8
Q
What is the standard concentration for H+
A
1.0x 10^-7
9
Q
What is the standard concentration for H2O
A
55.5 M
10
Q
What is the standard concentration for Mg2+
A
1 mM
11
Q
What is equilibrium
A
when the rates of forward and reverse reactions are equal
12
Q
At equalibrium are the concentrations of reactants and products equal
A
no
13
Q
While the concentrations are not equal at equilibrium, what has occurred to the concentrations at equilibriu
A
they reach a steady state
14
Q
Do organisms typically reach equilibrium, why or why not
A
no, because they would die due to no driving force
15
Q
When the ratio is greater than one, does the reaction favor the reactants or products
A
products
16
Q
If a reaction has a negative equilibrium constant, what does that indicate about the reaction
A
the reaction is exergonic, favorable under standard conditions
17
Q
For two reactions, how can you calciulate the standard free energy change
A
add the two reactions together because standard free energy changes are additive
18
Q
What is entropy
A
measure of randomness in an equation
19
Q
What is enthalpy
A
measures bonding
20
Q
Under favored conditions what is enthalpy
A
negative
21
Q
Under favored conditions what is entropy
A
positive
22
Q
under favored conditions what is free energy change
A
negative
23
Q
Why is metabolism used by the cell
A
to obtain chemical energy
convert nutrient molecules into cell’s molecules
polymerize monomeric precursors into macromolecules
synthesize and degrade biomolecules required for specialized cellular functions
24
Q
How does the cell obtain chemical energy
A
by capturing solar energy or degrading energy rich nutrients from the environment
25
According to the chemical form in which they use carbon from the environment, what two groups can living organisms be divided into
autotrophs
| hetertrophs
26
What are some autotrophs
photosynthetic bacteria, green algae, vascular plants
27
How do autotrophs obtain carbon
uses CO2 from atmosphere as their sole source of carbon
28
How do hetertrophs obtain carbon
complex organic molecules
29
Can heterotrophs obtain carbon through CO2
no
30
What are some heterotrophs
multicellular animals and most organisms
31
What are heterotrophs dependent upon
products of other organism
32
What are autotrophs dependent upon
nothing, they are self sufficient
33
Do all organisms need nitrogen
yes
34
How do bacteria obtain nitrogen
ammonia or nitrates
35
How do vertebrates obtain nitrogen
in forms of amino acids or other organic compounds
36
How does energy flow through the biosphere
one way
37
Why does energy only flow through the biosphere in one way
organisms cannot regenerate useful energy from energy dissipated as heat and energy
38
Can carbon oxygen and nitrogen recycle continuously
yes
39
Why can't the energy from these compounds be regenerated
energy is transferred into unusable forms such as heat
40
What is metabolism
sum of all chemical transformations taking place in a cellular organism
41
What allows these chemical transformations to take place
series of enzyme catalyzed reactions
42
What are these enzyme catalyzed reactions called
metabolic pathways
43
What does each step in the pathways cause
a removal, transfer, addition of an atom or functional group
44
What is a metabolite
metabolic intermediates
45
How does metabolite interact in the metabolic pathway
precursor is converted into a product through a series of metabolites
46
What is intermediatory metabolism
the combined activities of all metabolic pathways that interconvert precursors, metabolites and products
47
What is catabolism
degradative phase of metabolism
48
What occurs during catabolism
molecules are converted into smaller and simpler end products
49
What energy change occurs during catabolism
energy is released
50
In what types of forms is energy released
ATP and reduced electron carriers
51
What is anabolism
building phase of metabolism
52
What occurs during anabolism
biosynthesis, small simple precursors are built up into larger and more complex molecules
53
What types of molecules are built during anabolism
lipids, polysaccharides, proteins, nucleic acids
54
What energy change occurs during anabolism
required energy input
55
How is energy input into anabolism
phosphoryl group exchange and reducing power of NADH, NADPH, FADH2
56
What is a cyclic pathway
one starting component of the pathway is regenerated in a series of reactions that convert another starting component into a product
57
Can organisms do both anabolism and catabolism
yes
58
What occurs in organisms when anabolism is occurring
catabolism is suppressed (vice versa)
59
Because one pathway is suppressed, what must occur in order to not shut down both pathways
there must be different enzymes for both reactions/ pathways
60
What are the two ways that metabolic pathways are regulated
availability of the substrate
| allosteric regulation by a metabolic intermediate or coenzyme
61
When does the availability of the substrate have an impact on metabolic pathways
when near or below Km
62
What types of metabolic intermediates of conenzymes regulate metabolic pathways
amino acids, ATP, growth factors, hormones
63
What does bioenergetics study
energy transductions
64
What are energy transductions
changes of one form of energy into another
65
Where do energy transductions occur
in living cells, nature
66
What is the 1st law of bioenergetics
the total amount of energy in the universe remains constant, energy may change form or be transported from one region to another, but it cannot be created or destroyed
67
What is the 2nd law of bioenergetis
all natural process, the entropy of the universe increases
68
What is Gibbs free energy
amount of energy capable to do work during a reaction at constant temperature and pressure
69
a negative gibbs free energy is what
exergonic
70
a positive gibbs free energy is what
endergonic
71
What does enthalpy measure
heat content of the reacting system
72
What does enthalpy reflect
number and kins of chemical bonds
73
If a reaction released heat what is it
exothermic
74
If a reaction absorbs heat from its surrounding what is it
endothermic
75
What does entropy measure
the randomness or disorder in a system
76
A gain in entropy indicates what
more disorder
77
WHy is heat flow not a source of energy
heat can only do work as it passes to a zone or object at a lower temperature
78
Where does photosynthetic organisms get energy
solar radiation
79
Where do heterotropic get energy
nutrient molecules
80
What are solar radiation and nutrient molecules converted into
ATP
81
How is the standard transformed constants identified
written with prime '
82
If Keq' is greater than one, what is it's standard free energy change
negative
83
If Keq' is less than one, what is its standard free energy change
positive
84
When the standard free energy change is negative is the reaction spontaneous forward or backward
forward
85
Why is a negative free energy change spontaneous forward
products contain less free energy than the reactants
86
When standard free energy change is positive will the reaction be spontaneous forward or backward
backward reaction
87
WHy is a positive free energy change spontaneous backward
products contain more free energy than the reactants
88
What is the criteria for a system to be at equilibrium
rate of rxn forward is same going backward, no net change
89
Does the actual concentration of metabolites affect standard free energy change. WHy or why not
no, because when you calculate, you assume everything is 1M
90
Does the actual concentration of metabolites affect free energy change Why or why not
yes, you use this when testing under cellular or conditions other than standard
91
Metabolically irreversible reactions are what
reactions far from equilibrium
92
A reaction at equilibrium will have a delta G value of what
0
93
What is irreversible reaction in regards to free energy sign and magnitude, reactant/product concentrations
there is going to be a great amount of products in comparison to reactants, the free energy change value is going to be large and negative.
94
Which types of reactions are near equilibrium
reactions that only have a small energy change
95
Which type of reactions are far from equilibrium
reactions that have a large energy change
96
What is the energy that links catabolism and anabolism
ATP
97
Where do heterotropic cells obtain energy
catabolism of nutrient molecules
98
What do heterotropic cells use energy for
making ATP
99
What is ATP made from
ADP and P
100
What does ATP donate its chemical energy to?
endergonic processes
101
What are examples of endergonic processes
synthesis of metabolic intermediates and macromolecules from smaller precursors
transfer of substrates against its gradient
mechanical motion
102
What is the magnitude and sign for the free energy charge for ATP hydrolysis
Large and Negative
103
What does hydrolysis of ATP compose of
hydrolytic cleavage of the terminal phosphoric acid anhydride bond in ATP
104
What does cleaving the terminal phosphoric acid anhydride bond do
seperates one of the three negative charged phosphates
105
In cleaving one of the phosphates what is relieved
the electrostatic repulsion in ATP
106
How and Why is Pi stabilized
formation of several resonance structures
107
What is the standard free energy for ATP hydrolysis
-30.5kJ/mol
108
not under standard free energy changes what is the delta G
very different
109
Why is delta G different in actual conditions than the standard
cellular concentrations of ATP, ADP, Pi are not identical and much lower than 1.0M
Mg2+ binds to ATP and ADP which makes MgATP substrate
110
What is deltaGp
phosphorylation potential
111
What is phosphorylation potential
actual free energy of hydrolysis of ATP under intracellular conditions
112
Why can deltaGp differ between the cells
depends upon metabolic conditions and how ATP, ADP, Pi concentrations are altered
113
What is the free ADP in resting muscles estimated to be between
1 and 37 uM
114
Where should ATP concentrations be held in regards to equilibrium
far above for the hydrolysis reaction
115
When ATP levels drop, what occurs
amount of fuel decreases and the fuel loses potency
116
What are some other phosphorylated compounds
PEP
| 1,3 bisphosphoglycerate
117
What is PEP stand for
phosphoenolpyruvate
118
What does PEP contain structure wise
a phosphate ester bond
119
What does the phosphate ester bond undergo
hydrolysis
120
What does the phosphate ester bond undergoing hydrolysis yield
the enol form of pyruvate
121
What occurs to the enol form of pyruvate
it tautermerizes to the more stable keto form
122
What is the standard free energy of hydrolysis of PEP
-61.9 kJ/mol
123
What structure wise does the 1,3 bisphosphoglycerate molecule contain
anhydride bond
124
hydrolysis of 1,3 bisphosphoglycerate has what standard free energy change
-49.3 kJ/mol
125
When water is added across the anhydride bond of 1,3 bisphosphoglycerate, what is one of the direct products
3- phosphoglyverate
126
How many resonance forms does 3-phosphoglycerate have
two
127
In phosphocreatine, the P-N bond can be hydrolyzed to produce what
creatine and Pi
128
What is the delta G for phosphocreatine to creatin
-43.0 kJ/mol
129
What is a thioester
sulfur atom replaces the usual oxygen in the ester bond
130
What type of standard free energy changes occur for hydrolysis of thioesters
large, negative
131
How do thioesters compare to esters in regards to resonance
thioesters have less resonance stabilization
132
What does hydrolysis of esters produce
a carboxylic acid
133
What is the standard free energy for hydrolysis of esters
-31.4 kJ/mol
134
How do the produces vs reactants compare for reactions with a large neg. delta G
products are more stable than reactants
135
What is bond strain in reactants due to
electrostatic repulsion
136
How is electrostatic repulsion relieved
charge separation
137
How are the products of a reaction stabilized
ionization, isomerizations, resonance
138
ATP hydrolysis only accomplishes what
heat liberation
139
Can heat liberation drive a chemical process in an isothermal system
no
140
What is the first step of phosphate transfer
phosphoryl group is transferred to a substrate molecule or to an amino acid
141
How is the phosphate attached to the substrate molecule
covalently attached
142
How does covalently being attached affect free energy content
raises its free energy content
143
What is the second step of phosphate transfer
The phosphate is displaced generating, Pi, Pd or AMP
144
How does ATP participate to which it contributes free energy
covalently in the enzyme catalyzed reaction
145
How much energy can hydrolysis of ATP provide in regards to how much work can occur
enough to cycle proteins between two conformations
146
Cycling proteins between two conformations produces what
mechanical motion
147
What are the two groups phosphate compounds are divided into
high and low energy
148
What rule says a compound is high energy
the delta G is more negative than -25kJ/mol
149
What rule says a compound is low energy
the delta G is greater than -25kJ/mol
150
Why is breaking a bond and getting energy misleading
the bond does not contain energy
151
Breaking a bond is always what
endothermic
152
Where does the free energy result when breaking ATP bond
products of the reaction that have a lower free energy than the reactants
153
Reactions of ATP are what type of reactions
SN2 nucleophilic displacements
154
Each of the 3 phosphates are subject to what
nucleophilic attack
155
What is adenylation
attack at the alpha position, displaces PP and transfers adenylate as an adenyly group
156
What is adenylate
5'AMP
157
PP is hydrolyzed by what enzyme
pyrophosphatase
158
How much energy is released through pyrophosphatase
19 kJ/mol
159
What reactions fuel all work done in orgnaisms
redox
160
What is a reduced source of electrons
food
161
How do electrons move
via complex pathways
162
What do cells do to electrons
convert electrons into work
163
What does LEO says GER stand for
loss electrons oxidation
| gain electrons reduction
164
What is emf
electromotive force
165
Is electron affinity similar for all chemical species
no
166
When electrons flow through a circuit what do they produce
emf
167
When charge increases is this oxidation or reduction
oxidation
168
When charge decreases is this oxidation of reduction
reduction
169
is glucose oxidized or reduced
oxidized
170
electrons flow from what position to what position
lower to higher potentials
171
What does reduction potential depend upon
the specific activities
172
How does delta E relate to delta G
electron flow results in energy
173
What is the benchmark standard reduction potential reaction
H+ + e- to 1/2 H2
174
What is the reduction potential for the benchmark reaction
E=0V
175
true or false
| breaking any bond is always exothermic
false
176
True or False
| breaking any bond is always endothermic
true
177
Why is breaking any bond always endothermic
because bonds are stable
178
True or False
| whether breaking a bond is endothermic or exothermic depends on the bond
False
179
True or False
| Any reaction that involves ATP as a reactant will have a large negative deltaG
False
180
Why won't all reactions involving ATP have a large negative deltaG
if the products are more positive than reactants, this would lead to a positive deltaG
