Exam 1 Flashcards
(196 cards)
1
Q
What is the definition of metabolism?
A
Sum of all chemical reactions occurring in a living organism
2
Q
What does it mean if there is no energy change in a chemical reaction?
A
Nothing happens
3
Q
What are chemical reactions in living organisms catalyzed by?
A
Enzymes
4
Q
What are enzymes attempting to drive the reaction towards?
A
Equilibrium
5
Q
As enzyme catalyzed reactions proceed towards equilibrium what happens?
A
They release energy
6
Q
What happens when a reaction is farther from equilibrium?
A
It releases more energy/the more energy it can release
7
Q
What can the energy released in a chemical reaction be used for?
A
to do work, the remainder is unavailable
8
Q
In our muscles what is the energy that is not captured to do work released as?
A
Heat
9
Q
What is bioenergetics?
A
The study of the transformation of energy in living organisms
10
Q
What 4 things can energy be used for?
A
Anabolic part of metabolism, contraction, transport process, control mechanism
11
Q
What is the first law of thermodynamics?
A
In any physical or chemical change the total amount of energy in the universe remains constant, although the form of energy may change
12
Q
What is the second law of thermodynamics?
A
In all natural processes the entropy of the universe increases
13
Q
What does thermodynamics focus on?
A
The difference between initial and final states (changes delta)
14
Q
What is entropy?
A
randomness or disorder
15
Q
What is enthalpy (delta H)?
A
the change in energy of the reactions when turned into products
16
Q
How is enthalpy change measured?
A
As the total heat energy change (delta H)
17
Q
What is an exothermic reaction? What is it the negative value of?
A
When heat energy is given off in a reaction. delta H
18
Q
What limits can an endothermic reaction take place in? What is it the positive value of?
A
Can only occur with the input of energy or take up heat from surroundings. Positive value for delta H
19
Q
What is entropy change (delta S) a quantitative expression of?
A
The randomness or disorder in a system. Any change in the randomness of the system is the entropy change (delta S)
20
Q
What is entropy change a measure of? What does this tell us?
A
a measure of energy dispersal. Tells us that energy wants to move from where it is concentrated to where it is dispersed or spread out
21
Q
When does Delta S have a positive value?
A
Delta S has a positive value when the randomness increases
22
Q
What is free energy change (delta G)?
A
The maximum energy available from a reaction or process that can be harnessed to do something useful
23
Q
Of the total energy released in a reaction or process not all of it is available to _____
A
Do something useful
24
Q
What are 3 useful things that can be done with bioenergentics?
A
Muscle contracting and lifting a load, moving ions across a membrane against their concentration gradient, synthesizing proteins from amino acids
25
When free energy is released delta G is _____ and is called _____
Negative, exergonic
26
Between an exergonic and endergonic reaction which is favored, which is spontaneous (can occur by itself), and is delta G positive or negative?
Exergonic: delta G -, spontaneous, favored
Endergonic: delta G +, not spontaneous, not favored
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What do delta G, delta H, T, and delta S stand for?
delta G = free energy change, delta H = enthalpy change, T = absolute temp (Kelvin C+273=K), Delta S = entropy changes
28
What does delta G < 0 mean? _____ of the _____ is lower than the _____ of the _____
Free energy of the products is lower than the free energy of the reactants, exergonic
29
What is the formula for free energy changes?
Delta G = Delta H - T Delta S
30
When delta G > 0 is this reaction favored?
It is favored in the opposite direction even though it is endergonic
31
What does it mean when delta G = 0?
There is no free energy change
32
Is equilibrium static?
No, it is dynamic
33
What can't we measure in regards to quantifying free energy? What can we measure?
We cannot measure exact values associated with an initial and final state of a reaction in terms of enthalpy, entropy, and free energy. We can measure energy changes over the course of a reaction as changes in enthalpy, entropy, and free energy.
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1. The farther the reaction is from equilibrium, the _____ the value of delta G (as a _______ value)
1. Larger and negative
35
2. From an energy perspective, when the reaction begins which values will be large and which will be small?
2. A and B will be large, C and D will be small
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3. The natural logarithm and delta G will be ____ and _____ at the start of the reaction
3. Large and negative
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4. What happens to the values of A and B and C and D as the reaction proceeds toward equilibrium? What will happen to delta G
4. A and B will decrease and C and D will increase. Delta G will decrease but remain negative
38
What is the delta G naught value determined by?
5. It is determined by the value for the equilibrium constant
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6. What does the delta G naught reflect?
6. Reflects the energy generating potential for the reaction
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7. Why doesn’t the delta G naught value for a reaction define the actual energy change for the reaction inside a cell?
7. Because it depends on the relative concentrations of reactants and products
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8. What do cells exploit energy from to synthesize ATP?
8. Sunlight or food
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9. What is the base of adenine?
9. Nitrogen
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10. What is ribose made up of?
10. 5 carbon carbohydrate
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11. Hydrolysis of what linkages releases high amounts of energy?
11. Phosphoanhydride
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12. When can ATP be hydrolyzed?
12. At either linkage but not both at the same time
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13. Hydrolysis between the __ and ___ group is more common
13. Beta and gamma
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14. What does hydrolysis of linkage between beta and gamma phosphoryl groups yield?
14. ADP + Pi
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15. What does hydrolysis of linkage between beta and alpha phosphoryl groups yield?
15. AMP + inorganic pyrophosphate
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1. What is catabolism?
1. Degradation of large molecules into smaller molecules
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2. What are the 2 functions of catabolism?
2. Produce raw materials for the synthesis of macromolecules (anabolism), and release energy, part of which is used to synthesize ATP
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3. What type of process is anabolism? What is the definition?
3. Biosynthetic process, form molecules from smaller molecules
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4. What are 3 examples of anabolism?*****
4. Cell growth and division, replace damaged molecules, create energy deposits
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5. Is a substance oxidized or reduced when it loses or accepts one or more electrons?
5. Oxidation is losing, reduction is gaining
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6. Catabolic process usually involve oxidations of ________ this is known as _______
6. Metabolites, dehydrogenations
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7. Anabolic processes usually include reductions of _________ by the addition of __ this is known as _______
7. Metabolites, H, hydrogenations
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8. How are electron gain and loss connected in redox reactions?
8. Directly connected
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9. When does most of the energy needed by our bodies to grow and survive arise? What does it do first, then eventually?
9. When electrons on fuel molecules are transferred. First to coenzymes in dehydrogenation reaction then eventually to oxygen we breathe
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10. What are the 3 coenzymes?
10. NAD, NADP, FAD
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1. What 3 main features do enzymes share?*****
1. They increase reaction velocities, they have high specificity, their catalytic power is regulated
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2. What is the difference between a reversible and irreversible reaction? Which has a large energy change? Which is an equilibrium reaction? Which is more common?
2. Irreversible only goes one way, irreversible, reversible, reversible
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3. What is the average rate?
3. Change in the concentration of a reactant (substrate) or product divided by the time within this change is accomplished
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4. What does an enzyme increase in a reaction?
4. Rate
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5. The increase in V attributable to an enzyme indicates _____
5. Its catalytic power
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6. Free energy of activation is always _____
6. Always positive
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7. When the value of delta G++ is higher what happens to the activation of the substrates, and what happens to the speed of the reaction?
7. The harder the activation and the slower the reaction
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8. When enzymes bind substrate at an active site what does this expedite?
8. Expedites the formation of the transition state which lowers delta G++
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9. Enzymes increase reaction rate without doing what?
9. Without altering outcome of reactions
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10. What 5 factors affect rate of enzyme reactions?
10. Substrate concentration, enzyme concentration, temperature, pH, ionic strength
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11. _____ is higher as _____ is increased
11. Initial velocity, substrate
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12. What type of increase is a low S?
12. Linear increase
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13. What happens with a higher S?*****
13. V flattens out approaching a maximum velocity (Vmax)
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14. When V max is reached what does increasing S not produce?
14. Will not produce an increase in the rate of reaction
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15. What is each enzyme molecule working as fast as it can to do?
15. Converting S to P
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16. What is Michaelis constant?
16. If you determine Vmax, divide it in half, then determine what S will produce one half Vmax, we get a concentration known as Michaelis constant (Km)
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17. How is Km defined?
17. The substrate concentration needed to produce one half the maximal velocity of an enzyme catalyzed reaction
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18. What does the line weaver burk plot allow for?
18. Allows for accurate determination of the kinetic parameters of an enzyme catalyzed reaction
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19. Pertaining to the line weaver burk plot, what are values determined from?
19. Values are determined from intercepts on the horizontal and vertical exes
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20. When enzyme reaction follows Michaelis-Menton kinetics _____ over the range of substrate concentrations the L-B plot is _____
20. Hyperbolic, linear
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21. Number of _____ converted to _____ by an enzyme molecule in a specified time when the enzyme is fully saturated with _____
21. Substrate molecules, product, substrate
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22. What does a turnover number show?
22. Shows how fast an enzyme dispatches a reaction
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23. What is a turnover number also referred to as?
23. catalytic constant (Kcat)
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24. Some enzymes catalyze a given reaction, but what is different? (In different _____, but the enzymes have different _____ for the substrates)
tissues, kinetic parameters
83
1. If an enzyme is saturated with substrate and is thus working as fast as possible, what will adding more enzyme do?
Increases the reaction velocity
84
What is the enzyme proportional to?
2. Vmax
85
3. Does changing enzyme have an influence on Km? What is it important in determining?
3. No. Important in determining much a particular enzyme in a particular tissue
86
4. What happens to enzyme catalyzed reaction rate with an increased temperature?
It increases up to a poin
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5. What happens when it’s heated too much?
5. IT disrupts enzyme conformation and decreases activity
88
6. What temperature denatures enzymes?
6. ~50 degrees Celsius
89
7. What is the Q10 effect?
7. Describes the fold increase reaction rate for a 10 Celsius temp. For most biological processes, about 2
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8. What does change in H+ cause? How does this influence the active site?
8. Changes in H+ causes the addition or removal of protons from an enzyme molecule which may alter information. May directly influence active site
91
9. What pH range are enzymes active in? What is optimal for mammals?
9. Narrow range, ~7
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10. What may change in pH also alter?
10. May alter the substrate for the enzyme, could influence rate
93
11. Ions interacting with proteins could alter what?
11. Tertiary and quaternary structures
94
12. What happens to enzymes when ionic strength is too high or too low?
12. Many enzymes are denatured
95
13. The activity of a variety of enzymes in the cell may be modified so that _________ is appropriate
13. Cellular metabolism
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14. Simple enzymes obeying simple _____ kinetics are common but rarely observed in _____ metabolism
14. Michaelis-Menten, controlling
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15. What are two types of regulation of enzyme activity?
15. Allosteric enzymes, covalent modification of enzymes
98
16. What does activity of allosteric enzymes depend on?
1. What is this usually comprised of?
2. This is typically at points in metabolic pathways where ______
16. S and P and the presence of positive or negative effectors
1. Multiple subunits with multiple active sites
2. They control overall pathway rate
99
17. Postive allosteric effectors = and negative allosteric effectors =
17. Postive = activators, negative = inhibitors
100
18. Activator and inhibitors can be _____ or _____ of allosteric enzyme or other _____
18. Substrate or products or other molecules (ligands)
101
19. What does concentration provide a message about?
19. How active the allosteric enzyme should be
102
20. Effectors can bind to either _____ or _____ on enzyme
20. Active site or allosteric sites
103
21. Activity of some enzymes can be rapidly turn on or off by what?
21. Covalent modification of specific amino acid residues in the enzyme
104
22. What can an addition of a phosphate group do?
22. Drastically alter a protein (reversible)
105
23. Phosphate is _____ and has _____
23. Very large, 2 negative charges
106
1. What is an example of carbs being external protection for some cells?
1. Cellulose
107
2. What can carbs help cells recognize?
2. Molecules or other cells in environment
108
3. Carbs are part of a building block for what?
3. Nucleic acids
109
4. How many carbon atoms are in tetrose, hexose, pentose, heptose, and triose?
4. Tetrose = 4, hexose = 6, pentose = 5, heptose = 7, triose = 3
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5. _____ and _____ are the smallest monosaccharides
5. Glyceraldehyde and dihydroxyacetone
111
6. Both are isometric but the carbonyl groups are _____
6. in different positions
112
7. What is the carbonyl group at end of carbon chain?
7. Aldose
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8. What is the carbonyl at any other position?
8. Ketose
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9. What is an example of a pentose?
9. Ribose (C5H10O5)
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10. What two formations can a pentose have?
10. Open chain or cyclic formation
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11. Cyclic form is predominant in what?
11. In biological fluids
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12. What is a five member ring with one O and four C?
12. Furanose (ribofuranose)
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13. What are the two possible isomers?
13. Alpha and beta
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14. What are 2 examples of a hexose?
14. Glucose (C6H12O6) and Fructose (C6H12O6)
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15. What is a six membered ring with one O and 5 C?
15. Open chain and pyranose
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17. What position is the carbonyl in? As opposed to?
17. Position 2 in open chain, as opposed to position 1 in glucose
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1. How many covalently linked monosaccharides are oligosaccharides?
2-10
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2. What are 2 examples of a disaccharide?
Maltose (glucose + glucose) and Sucrose (glucose + fructose)
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3. What is the most abundant category of carbohydrates?
3. Polysaccharide
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4. How many monosaccharide units are in a polysaccharide?
4. More than 10
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5. What are 3 examples of a polysaccharide?
5. Cellulose (linear chains), starch, glycogen
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6. Glycogen is a _____ of glucose
6. Homopolysaccharide
128
7. Where is glycogen primarily found?
7. Liver and muscle
129
1. What are 4 examples of lipids?
1. Fatty acids, triacylglycerols, phospholipids, steroids
130
2. Fatty acids are organic acids that contain what?
2. Relatively large numbers of carbons (12-26)
131
3. At physiological pH carboxyl group is _____
3. Hydrophilic
132
4. Alphatic chain is _____
4. Hydrophobic
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5. Fatty acids are _____
5. Amphipathic pr amphiphilic
134
6. Are fatty acids soluble in water?
6. No, they are poorly soluble in water
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7. Most fatty acids contain _____ numbers of carbon
Even
136
8. How are fatty acids synthesized?
8. By joining acetyl groups
137
9. What do fatty acids differ in?
9. Number of double bonds
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10. What are saturated fatty acids?
10. Carbons of fatty acids linked by single bonds only
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11. What are unsaturated fatty acids?
11. Double bonds between some of the carbons
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12. What are 2 examples of unsaturated fatty acids?
12. Monounsaturated, polyunsaturated
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13. What 2 configurations can an unsaturated fatty acid have?
13. Cis and trans configuration
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14. What is the most abundant category of lipids?
14. Triglycerides
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15. What are triglycerides the main component of?
15. Animal and human fat, vegetable oils
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16. What do triglycerides serve mainly as?
16. Energy depots
145
17. What 2 things do triglycerides consist of?
17. Glycerol (glycerin) unit and 3 fatty acid units
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18. Are all triaglycerols hydrophobic or hydrophilic?
18. Hydrophobic
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19. The main group of phospholipids are derivatives of _____
19. Phosphatidate
148
20. What is the parent compound of all steroids and a component of the membranes of animal cells?
20. Cholesterol
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1. ATP free energy change: delta G naught for ATP is _____ and ____
large and negative
150
2. What is delta G naught equal to under standard conditions?
2. -30.5 kJ/mol (-7.3kcal/mol)
151
3. What are concentrations of ATP, ADP, and Pi like in living cells? How does this compare to the standard 1.0 M concentrations?
3. Are not identical and are much lower
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4. The cytosol contains _____ which binds to _____ and _____
4. Mg2+, ATP, ADP
153
5. In most enzyme reactions that involve ATP as a phosphoryl donor what is the true substrate?
5. MgATP2-
154
6. Delta G for ATP hydrolysis in intact cells (usually denoted as delta Gp) ranges from _____ to _____
6. -50 to -65 kJ/mol
155
7. Delta Gp is often called the _____
7. Phosphorylation potential
156
8. What kind of a process are many cellular reactions for which ATP supplies energy NOT? What is it actually?
8. NOT a simple one step process, actually a 2 step process
157
9. ATP group transfers vs simple hydrolysis: Part of the ATP molecule (phosphoryl group or adenylate moiety (AMP) is first transferred to a _____ or _____
9. Substrate molecule or an amino acid residue on an enzyme
158
10. What does this covalent attachment do?
10. Raises the free energy of the substrate or enzyme
159
11. What happens in the second step?
11. The phosphate containing moiety is displaced generating either Pi or AMP
160
12. One important exception: those process in which non covalent binding of ATP followed by hydrolysis to ADP and Pi provide the energy to _____
12. The energy to cycle a protein between two conformations producing mechanical motion
161
13. Exercise stimulates 3 of 4 processes that require ATP: _____
13. Cross bridge cycle, protein movement (molecular motor), signal amplification (could be coming from 2nd messenger, intracellular mechanism, calcium induced) (4th not enhanced during exercise but pre and post exercise: anabolism)
162
14. What do these processes during exercise result in?
14. Increased ATP breakdown
163
15. Catabolism is activated to do what?
15. To meet the increased demand for ATP
164
16. What is accelerated during exercise?
16. The entire ATD-ADP
165
17. What is ATP content of a skeletal muscle at rest?
17. 6mmol/kg
166
18. As the muscle begins to contract what happens to cytosolic ATP?
18. Cytosolic ATP decreases rapidly
167
19. How fast would ATP vanish during maximal contraction if sources and processes to replenish ATP were not in place?
19. 3 seconds
168
20. As _____ decreases during exercise, _____ and _____ increase
20. ATP, ADP, Pi
169
21. What is the formula showing that AMP increases?
21. 2 ADP <> AMP + ATP
170
22. AMP? Is catalyzed by _____ or _____ because of its high level in muscle
22. Adenylate kinase or myokinase
171
23. What is a synonym of AMP?
23. Adenylate
172
24. What are kinases?
24. Enzymes catalyzing phosphorylation of compounds using ATP (adenylate kinase named for reverse reaction in example)
173
25. How are creatine and creatine phosphate levels in muscle?
25. Considerably high
174
26. What substrate is creatine even though it doesn’t make up proteins?
26. Amino acid
175
27. What attachment is PCr derived from?
27. The attachment of a phosphoryl group to one of creatine’s nitrogens
176
28. What is the fastest source of ATP resynthesis? When is this valuable?
28. PCr, valuable during maximal exercise
177
29. What time frame does regeneration of ATP from ADP happen?
29. In a single reaction
178
30. Which has a higher phosphoryl transfer potential, ATP or CP?
30. CP
179
31. What is the use of PCr to regenerate ATP sometimes referred to as?
31. Anaerobic alactic system
180
32. What two things does it not ___
32. Does not need O2, does not generate lactate
181
33. What happens at the onset of very vigorous activity? What happens to PCr, ATP, and Cr?
33. Creatine kinase (CK) drives this reaction to the right. PCr depleted, ATP maintained, Cr increases
182
34. What is the formula for phosphocreatine system?
34. PCr + ADP + H+ <> CK ATP + Cr… Delta G naught = -3kcal/mol
183
35. Consumption of _____ during reaction is also _____ during high intensity exercise
35. Proton, beneficial to muscle
184
1. How many genes for CK are present in mammals?
1. 4
185
2. What type of cytosolic CK is found in the brain, heart, and skeletal muscle?
2. CK-BB (CK1)=brain, CK-MB (CK2)=heart, CK-MM (CK3)=skeletal muscle
186
3. What sites are cytosolic isoforms located at?
3. Sites where ATP is hydrolyzed and regenerated (near myosin heads, inner side of sarcolemma, outer face of SR)
187
4. Mitochondrial: involved in facilitation of _____
4. Oxidative phosphorylation
188
5. CK activity can maintain _____ levels very well during intense exercise
1. Substantial _____ effect
5. ATP
1. ATP-buffering
189
6. What kind of power for regenerating ATP does CK have?
6. High power
190
7. What are PCr levels in resting human skeletal muscle? What is the wet muscle weight?
7. ~18-20 mmol/kg, 23-26mM
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8. Is the supply of PCr abundant or limited?
8. Limited
192
9. What capacity does the phosphocreatine system have?
9. Low capacity
193
10. During exercise _____ falls in proportion to the _____
10. PCr, relative intensity of exercise
194
11. In all out efforts how much can PCr change by?
11. Decrease by 90% or more
195
12. When does the reserve of the CK reaction dominate?
12. During recovery or rest periods
196
13. Phosphate transfer to creatine from ATP produced from what regenerates what?
1. ATP _____ process
2. Derived from _____
13. From oxidative phosphorylation regenerates PCr
1. Consuming
2. Aerobic metabolism
