Exam I Flashcards
(210 cards)
1
Q
What is thermodynamics?
A
Energy change and heat transfer
2
Q
What is free energy?
A
Measure of how a reaction will proceed via enthalpy and entropy (delta G)
3
Q
What is Enthalpy?
A
Heat content (delta H)
4
Q
What is entropy?
A
Randomness of disorder (stats, delta S)
5
Q
1st law of thermodynamics states that ….
A
Energy isn’t created or destroyed, potential —> kinetic
6
Q
2nd law of thermodynamics states…
A
Entropy always increases, spontaneous not instantaneous
7
Q
Exergonic free energy is …
A
(-) delta G gives off energy, spontaneous, enthalpy, heat content, decreases or entropy, disorder, increases or both
8
Q
Endergonic free energy is …
A
(+) delta G absorbs energy, non-spontaneous, energy required, enthalpy increases or entropy decreases
9
Q
Delta G balances out with equal…
A
Exergonic and endergonic free energy
10
Q
Standard free energy is…
A
Delta G constant value with reactants and products = 1mol/L
11
Q
K=eq is…
A
Product/reactant
12
Q
Activation energy is…
A
Energy required to initiate chemical reaction
13
Q
Larger activation energy proceeds more _____.
A
Slowly
14
Q
Does larger activation energy increase/decrease with heat/catalyst?
A
Increases with heat
Decreases with catalyst
15
Q
Enzymes are…
A
Protein catalysts that Increase rate of reaction, -ase suffix
16
Q
There are how many classes of enzymes?
A
6
Oxidoreductase, Transferase, Hydrolase, Lyase, Isomerase, Ligase
17
Q
Oxidoreductase is a catalyst for what?
A
Oxidation, reduction
18
Q
Transferase is a catalyst for what?
A
Transfer of C-, N-, P-
19
Q
Hydrolase is a catalyst for what?
A
Cleavage of bonds by adding H2O
20
Q
Lyase is a catalyst for what?
A
Cleavage of C-C, C-S, and some C-N bonds, cuts or decarbonates
21
Q
Isomerase is a catalyst for what?
A
Racemitation of optical or geometric isomers, rearranges
22
Q
Ligase is a catalyst for what?
A
Formation of bonds between C and O, S, N coupled to hydrolysis of high energy phosphates, glues together
23
Q
Allosteric enzymes are regulated by what?
A
Molecules called effectors (modifiers) that bind non-covalently at a site other than the active site
24
Q
Allosteric enzymes are usually composed of ______ subunits.
A
Multiple
25
The regulatory site that binds the allosteric enzyme may be located on a subunit that is not itself _______.
Catalytic
26
The presence of an allosteric effector _____ alter the affinity of enzyme for its substrate and/or _____ modify the max catalytic activity.
Can do either or both
27
Effectors that inhibit enzyme activity are termed _____ effectors, whereas those that decrease enzyme activity are called _____ effectors.
Negative, positive
28
Allosteric enzymes frequently catalyze the commuted step ____ in a pathway.
Early
29
Which effectors have substrates serving as their own effector?
Homotrophic
30
Which effectors may be different from their substrate?
Heterotrophic
31
The active site contains ____ side chains that participate in substrate binding and catalysis.
Amino acids
32
What is thought to cause conformational change in the enzyme that allows catalysis?
Enzyme-substrate
33
Enzyme-substrate is converted to ____ that subsequently dissociates to ____ and ____.
Enzyme-product, enzyme and product
34
Energy of activation is...
Energy difference between reactants and a high-energy intermediate that occurs during product formation.
35
High free energy of activation leads to ____ rates of uncatalyzed reactions.
Slow
36
Factors affecting reaction velocity include:
Substrate concentration, temperature, and pH
37
Max velocity and hyperbolic shape of enzyme kinetics curve dictate the ____.
Substrate concentration
38
____ enzymes do not follow Michaelis-Menten kinetics and show a sigmoid curve.
Allosteric
39
The reaction velocity increases with temperature until a ____ velocity is reached.
Peak
40
Too much heat may cause a temperature-induced ___ of the enzyme.
Denaturation
41
Reaction velocity is affected by pH’s effect on ____, ____, and ____.
The ionization of the active site, enzyme denaturation, enzyme specific optimum pH level
42
The structure of the catalytically active protein molecule depends on the ____ of the amino acid side chains.
Ionic character
43
Catalytic activity may require that a(n) ____ of the enzyme be in the probated form.
Amino group
44
Line Weaver-Burk Plot
Calculates Km (Michaelis constant) and maximum velocity, as well as to determine the mechanism of action of enzyme inhibitors.
45
Enzyme inhibition consists of ____ and ____ inhibition.
Competitive and noncompetitive
46
Competitive inhibition occurs when the inhibitor binds to the ____ site that the substrate would normally occupy.
Active
47
Competitive inhibition effects ____, ____, ____, and ____.
Maximum velocity, Michaelis constant, Lineweaver-Burk Plot, and cholesterol levels (synthetically)
48
Maximum velocity effect reversed by ____ substrate levels.
Higher
49
In the ____ of a competitive inhibitor, more substrate is needed to achieve 1/2 maximum velocity.
Presence
50
Michaelis constant is ____ in the presence of the competitive inhibitor.
Increased
51
____ is the most common type of noncompetitive inhibition.
Allosteric inhibition
52
An increased concentration of substrate cannot overcome noncompetitive inhibition leads to a decreased ____.
Maximum velocity
53
Michaelis constant ____ in the presence of a noncompetitive inhibitor and ____ in the absence of a noncompetitive inhibitor.
Stays the same, Stays the same
54
In regards to the Lineweaver-Burk plot when looking at a noncompetitive inhibitor has an apparent maximum velocity ____, with the Michaelis constant ____.
Decreases, unchanged
55
Some noncompetitive inhibitors act by forming ____ with specific groups of enzymes.
Covalent bonds
56
Ionic or hydrogen bonding, or even covalent bond bound ions and cations are ____.
Cofactors
57
Subset of cofactors that are organic molecules with dietary vitamins being very common molecules are called ____.
Coenzymes
58
____ is an energy carrier with a high activation energy.
ATP
59
Many coupled reactions use ATP to generate a common ____.
Intermediate
60
Large (-) free energy (delta G) has a ____ energy phosphate compound.
High
61
Keq = 1 and free energy (delta G) = 0 relationship is ____.
At equilibrium
62
Keq > 1 and free energy (delta G) < 0 relationship is ____.
Favors products
63
Keq < 1 and free energy (delta G) > 0 relationship is ____.
Favors reactants
64
Coupled reactions are often ___ with 1st reaction without 2nd reaction coupled with the 1st reaction.
Not favorable
65
The double coupled reactions usually have ____ and ____.
Slower step, faster step
66
2-multi step coupled reactions often have ____.
Intermediates
67
For coupled reactions, when there is more than ____ step, overall process is calculated by adding the energy from all steps.
One
68
____ has the ability to donate protons to an acceptor.
Acid
69
Strong acids dissociate ____ to their respective ions
Completely
70
Diprotic acids have ____ protons to donate.
| Sulfuric acid
2
71
With diprotic sulfuric acid, step ____ is nonreversible and step ____ is reversible.
1, 2
72
Triprotic acids have ____ acids to donate.
| Phosphoric acid
3
73
Weak acids ____ dissociate completely into hydrogen acids and conjugate bases.
Don’t
74
Strong ____ dissociate completely to their ions.
Bases
75
Weak ____ do not dissociate completely.
Bases
76
Ka, dissociation constant, measures...
How much of the acid will dissolve into its hydrogen ions and conjugate base ions
77
For Ka, (H20) concentration is ____ because molarity (concentration) of H20 is very high compared to other species.
Held constant
78
PKa= ____
A/B Amino Acid
79
Lower pKa = ____
Higher acid
80
Higher Hydrogen levels = ____ pH
Lower
81
____ Resists pH change following the addition of an acid or a base.
Buffers
82
Mixing weak acid with conjugate base yields ____.
Buffer
83
Max buffering capacity occurs when pH ____ pKa.
Equals
84
Conjugate acid/base pair can still serve as an effective buffer when pH is within ____ pH of the pKa.
Give or take 1
85
If weak acid and conjugate base are equal, pH ____ pKa.
Equal
86
When pH ____ pKa, pronated acid form is predominant species.
Lesser than
87
When pH ____ pKa, depronated base form is predominant species.
Greater than
88
____ pH at which net charge is 0.
Isoelectric point
89
Amino acid titration begins with ____ followed by amino acid dissociation.
Carboxyl group
90
Henderson-Hasselbalch Equation is...
Examination of pH with addition of acids/bases
91
Protein structure which determines sequence of amino acids linked by peptide bonds.
Primary structure
92
Proteins named from free ____ terminus to free ____ terminus
N, C
93
What enzyme hydrolyzes peptide bonds?
Peptidases
94
Protein structure with alpha-helix spiral and/or beta-sheet.
Secondary structure
95
Protein structure stabilized by H bonds between carbonyl oxygen and amide hydrogen.
Secondary Structure
96
Protein structure with H bonding, 2+ peptide chains or single folded chain.
Secondary structure
97
Protein structure forms 3D structure stabilized by S-S bonds, hydrophobic interactions, H bonding, and ionic interactions (cofactors).
Tertiary structure
98
What helps and maintains protein folding?
Chaperones
99
Denaturation can occur from...
Heat, organic solvents, strong acids/bases, detergents, heavy metals.
100
Protein structure with 2+ subunits which are held together by H bonds and hydrophobic interactions. Occasional S-S bond.
Quaternary Struture
101
Abnormal proteins created by spontaneous misfolding/mutations.
Amyloid disease
102
Parkinson’s, Huntington’s, and Alzheimer’s diseases develop from what protein dysfunction?
Amyloid plaque
103
Pathogen mutation of prion protein (mad cow disease)
Prion disease
104
Myoglobin is a ____ polypeptide chain of hemoglobin.
Single
105
Myoglobin has a(n) ____ secondary structure.
A-helix
106
Polypeptide chain terminated by presence of ____ in myoglobin.
Proline
107
Oxygen binding of myoglobin binds ____ molecule because of the ____ heme group.
Single, single
108
Hemoglobin contains ____ polypeptide chain(s), ____ a-helix, and ____ beta chains held together noncovalently.
4, 2, 2
109
T form is ____ with 2 alpha-beta diners which constrain movement. Low oxygen affinity.
Tense
110
R form is ____ H and ionic bond rupture leads to more movement. High oxygen affinity.
Relaxed
111
Bohr Effect states when ____ is lowered or ____ is elevated, oxygen affinity increases.
PH, CO2
112
Michaelis-Menien kinetics graph:
Affinity and substrate have inverse relationship while km and substrate have a positive relationship
113
RNA sugar
Ribose
114
RNA and DNA
RNA- A+U and C+G
| DNA- A+T and C+G
115
Fatty acid functional group is...
Ester
116
Protein functions include:
Enzyme catalysis, defense, transport, motion, storage, and regulation
117
(-) delta G is ____.
Favorable, spontaneous
118
(+) delta G is ____.
Unfavorable
119
If keq=1 and delta G=0 a system _____.
Is in equilibrium
120
When consuming a sandwich, your body cannot process the alpha D-glucose.
True or False
False
121
Sucrose is a combination of which monosaccharides?
Fructose + Glucose
122
Domains are found on which structure?
Tertiary and Quaternary
123
What organic molecule in RBCs decreases oxygen binding affinity?
2,3-BPG
124
What class of enzyme is used to break glycosidic bonds or peptide bonds?
Hydrolase
125
Statin drugs function as noncompetitive inhibitors.
| True or False
False
126
What disaccharide is formed with a monosaccharide of glucose and a monosaccharide of galactose?
Lactose
127
Endergonic reactions are reactant favored.
| True or False
True
128
Which amino acid forms disulfide bonds?
Cysteine
129
The Henderson-Hasselbalch equation:
Relates the pH of a solution to its pKa
130
Which of the following would not cause a right shift in the oxygen-dissociation curve for Hb?
Lower concentration of Hydrogen ions
131
Which of the following would cause a left shift in the oxygen-dissociation curve for Hb?
Higher pH
132
Hb groups will bind to CO before O.
| True or False
True
133
Hemoglobin has greater binding ____, but myoglobin has greater binding ____.
Capacity, affinity
134
What are factors affecting enzyme kinetics?
Substrate concentration, pH, and temperature
135
What applies to non-competitive inhibition?
Km is unaffected, maximum velocity is lower
136
According to Michaelis-Menten Kinetics, the rate of the reaction is directly proportional to ____.
Enzyme concentration
137
Which of the following classes uses water to remove a phosphoryl group?
Phosphatase
138
Enzyme catalysts do not ____.
Make endergonic reactions spontaneous
139
The binding of oxygen to one subunit decreases the affinity for oxygen to find to the other 3 subunits.
True or False
False
140
Achiral amino acid
Glycine
141
A buffer is ____.
A solution that resists changes in pH when acids or bases are added to it.
142
Tyrosine is part of which classification group?
Uncharged polar
143
The 2 strands of DNA are connected by what type of bond?
Hydrogen bond
144
A coupled reaction will not ____.
Have the overall delta G being positive
145
Has high ability to form water because of the abundance of hydrogen ____.
Strong acid
146
Reaction that is product favored?
Exergonic
147
Irreversible or “suicide” inhibitors such as lead form ____ to permanently inhibit an enzyme.
Covalent bonds
148
Enzyme responsible for only changing arrangement?
Isomerase
149
Proteins are metabolically available in the D form.
| True or False
False
150
What is the difference between a strong acid and a weak acid?
A strong acid will dissociate completely, a weak acid will ionize to only a limited extent.
151
When pH < pKa, molecule is pronated.
| True or False
True
152
The human body can break down
Alpha 1->6
153
When delta G is positive, ____.
It is endergonic
154
The active site contains ____ side chains that participate in substrate binding and catalysis.
Amino Acids
155
Allosteric regulation changes ____.
Activity of enzyme by binding an effector
156
Lowering the pH will cause what to occur on the oxygen affinity plot of Hb?
A decrease in O2 affinity and a shift to the right
157
The reaction velocity increases with temperature until a ____ velocity is reached.
Peak
158
At what partial pressure is myoglobin more likely to get oxygen than hemoglobin?
Lower
159
The 2 monosaccharides that make up a disaccharide are linked together via ____.
Dehydration synthesis
160
The human body can process both L-sugars and D-proteins.
| True False
False
161
A double helix of DNA consists of 2 polynucleotide strands connected by what type of bond?
Hydrogen
162
Non-competitive inhibition ____.
Decreases maximum velocity
163
Competitive inhibition ____.
Can be overcome by increasing substrate concentration
164
According to the Bohr effect, when pH decreases ____.
Hemoglobin is in deoxy form
165
A structure that has hydrogen bonds between polypeptide chains arranged side by side are ____/
B-pleated sheets
166
Carbohydrates have a ____ ratio of C:H:O
1:2:1
167
Which kind of amino acids are in the hydrophobic tail of the phospholipid bilayer?
Nonpolar
168
The free energy of hydrolysis of a compound must be at least ____, in order for it to be considered a “high-energy” compound.
-7 kcal/mol
169
If a reaction is at equilibrium, the free energy change (delta G) is ____.
Equal to 0
170
What is special about glycine? Why?
It is achiral because it doesn’t have 4 different bonding sites.
171
3 letter code for Cysteine
Cys
172
3 letter code for Histidine
His
173
3 letter code for Isoluecine
ile
174
3 letter code for Methionine
Met
175
3 letter code for Serine
Ser
176
3 letter code for Valine
Val
177
3 letter code for Alanine
Ala
178
3 letter code for Glycine
Gly
179
3 letter code for Leucine
Leu
180
3 letter code for Proline
Pro
181
3 letter code for Threonine
Thr
182
3 letter code for Arginine
Arg
183
3 letter code for Asparagine
Asn
184
3 letter code for Aspartate
Asp
185
3 letter code for Glutamate
Glu
186
3 letter code for Glutamine
Gln
187
3 letter code for Phenylalanine
Phe
188
3 letter code for Tyrosine
Tyr
189
3 letter code for Tryptophan
Trp
190
3 letter code for Lysine
Lys
191
Collagen secondary structure.
A-helix
192
____ acids serve as good buffers.
Weak
193
Subunits on quaternary structures are protein dependent.
| True or False
True
194
High pH has ____ hydrogen ion concentration compared to low pH.
Lower
195
C-C bonds do not contribute to the stability of tertiary structure of protein.
True or False
True
196
Raising pH causes a shift to the L of sigmoidal curve on oxygen affinity plot of Hb.
True or False.
True
197
Denaturation of proteins won’t happen with strong base.
| True or False
True
198
Peptide bonds are made of amides.
| True or False.
True.
199
Glucose + Glucose = ____
Maltose
200
Glucose + Fructose = ____
Sucrose
201
Glucose + Galactose = ____
Lactose
202
Functional Group:
OH-
Alcohol
203
Functional Group:
/\
NH2
Amine
204
Functional group:
/\
SH
Thiol, di-sulfide potential when oxidized for stability
205
Functional group:
o=
Ketone
206
Functional group:
H
o=<
Aldehyde
207
Functional group:
OH
o=
Carboxylic acid
208
Functional group:
NH2
o=
Amide
209
Functional group:
O—
-o=
Ester
210
Functional group:
/\o/\
Ether
