Block 1 Flashcards
(426 cards)
1
Q
what do enzymes increase
A
speed of reaction
2
Q
what type of molecule are most enzymes
A
proteins
3
Q
what is an apoenzyme
A
enzyme without its co-factor
non functional
4
Q
a cofactor that is tightly bound to the enzyme is called what
A
prosthetic group
5
Q
cofactors that are complex organic molecules are called what
A
coenzymes
6
Q
what are isoenzymes
A
same enzyme, different structure
7
Q
what is a zymogen
A
an inactive enzyme that must be cleaved to become active
8
Q
what are 2 examples of zymogens
A
trypsin and chymotrypsin
9
Q
what are the 4 basic steps of enzyme catalyzed reactions
A
- binding of substrate
- formation of enzyme substrate complex
- conversion of substrate to product
- release of product from active site
10
Q
the active site of an enzyme is composed of the __ site and the __ site
A
catalytic and substrate binding
11
Q
what does the induced fit model tell
A
interaction of substrate with enzyme induces conformational changes so the binding is a better fit
12
Q
what do enzymes reduce
A
activation energy
13
Q
what is the transition state for enzymes
A
peak of energy curve where reactants convert to products
14
Q
what is involved in catalysis by bond strain
A
rearrangement when enzyme is bound to substrate induces strain
15
Q
what is involved in covalent catalysis
A
formation of a covalent intermediate
16
Q
what is an example of a covalent intermediate in covalent catalysis
A
serine proteases
17
Q
what amino acids make up the serine protease triad
A
histidine
serine
glutamate (or aspartate)
18
Q
co-enzymes are often what
A
water soluble vitamins
19
Q
increased transcription of a gene or decreased proteolysis of enzyme protein increases or decreases enzyme activity
A
increases
20
Q
effect of temperature on enzyme activity
A
too high= denature
too low= slow down
21
Q
pH effect on enzyme activity
A
too high or low= denature
22
Q
what is Km
A
the substrate concentration at 1/2Vmax
23
Q
small Km means high or low enzyme affinity for substrate
A
high
24
Q
high enzyme affinity means high or low substrate concentration
A
low
25
what do oxido-reductases do
transfer H+ or e-
26
what do hydrolases do
cleave bonds by addition of water
27
what do transferases do
transfer a group (not hydrogen or oxygen) from one molecule to another
28
what do isomerases do
interconvert isomers
29
what do lyases do
alter bonds without addition of water
30
what do ligases do
link 2 molecules
31
what is hydrolysis
bond cleavage by addition of water
32
what do racemases and epimerases do
interconvert optical isomers
33
what do dehydrogenases do
remove H
34
what does the y intercept represent in lineweaver burk plots
1/Vmax
35
what does the x intercept represent in lineweaver burk plots
-1/Km
36
what are 3 classifications of reversible inhibitors
competitive
noncompetitive
uncompetitive
37
where does the inhibitor bind in competitive inhibition
active site
38
where does the inhibitor bind in noncompetitive inhibition
allosteric site (changes shape)
39
where does the inhibitor bind in uncompetitive inhibition
enzyme-substrate complex
40
what effect does competitive inhibition have on Vmax and Km
Vmax unchanged
Km increases
41
what is an example of a competitive inhibitor in the citric acid cycle
malonate with succinate for succinate dehydrogenase
42
what is an example of a drug that is a competitive inhibitor
viagra
43
what effect does noncompetitive inhibition have on Vmax and Km
Vmax decreases
Km unchanged
44
what type of reversible inhibition can be reversed by increasing substrate concentrations
competitive inhibition
45
what effect does uncompetitive inhibition have on Vmax and Km
both decrease
46
what is an example of an uncompetitive inhibitor used to treat manic depression
lithium
47
what effect does irreversible inhibition have on Vmax and Km
Vmax decreases
Km unchanged
*same effects as reversible noncompetitive inhibition
48
irreversible inhibition has the same effects on Vmax and Km as what type of reversible inhibition
noncompetitive
49
what is an example of a toxin that is an irreversible inhibitor
cyanide
50
how does cyanide act as an irreversible inhibitor
binds to cytochrome oxidase and inhibits complex IV of ETC
51
what is an example of an irreversible inhibitor type of drug
aspirin
52
how does aspirin work
inhibits cyclo-oxygenase (COX) -->decreased pain and inflammation
53
what is an example of a reversible inhibitor drug that acts in the same way as aspirin
ibuprofen
54
what is an example of an allosterically regulated protein
PFK-1
55
what does phosphatase do
removes phosphate
56
what are the usual sites for phosphate addition to proteins (3 amino acids)
serine
threonine
tyrosine
57
does phosphorylation of glycogen phosphorylase activate or inactivate glycogen utilization
activates
58
does phosphorylation of glycogen synthase inhibit or activate glycogen synthesis
inhibit
59
what is enthalpy
amount of heat absorbed or released
60
what is the symbol for enthalpy
delta H
61
in endothermic reactions, are reactants or products at a higher energy level
products
62
are endothermic reactions anabolic or catabolic
anabolic
63
what does bioenergetics describe
transfer and utilization of energy
64
do catabolic or anabolic reactions release heat
catabolic
65
what is the standard free energy for each of the 2 terminal phosphates that ATP can release
-7.3 for each
66
what is Gibbs free energy
energy available to do work
67
what do negative delta G^0' tell
it is an exergonic reaction proceeding to the right (to lower energy state)
spontaneous
68
what do positive delta G^0' tell
it is an endergonic reaction proceeding to the left (to lower energy state), nonspontaneous
69
phosphorylation of glucose by ATP is catalyzed by what 2 enzymes
hexokinase and glucokinase
70
what is involved in reaction coupling
product of one reaction is the reactant of another
71
what is the common intermediate compound in coupled reaction in living cells
ATP
72
how can all sugars be activated
by adding a nucleotide
73
what is reduction potential a measurement of
the tendency for a substrate (reactant) to accept electrons
74
how can the proportions of NAD+ and NADH in a solution be determined
UV absorption spectra
75
a high value at 340nm in UV absorption tells us there is high or low NADH content
high
76
how is UV spectrophotometry used for lactate dehydrogenase
pyruvate-->lactate, NADH is consumed= decrease in absorbance at 340nm
lactate-->pyruvate, NADH is produced= increase in absorbance at 340nm
77
why is ATP called a high energy phosphate compound
it has a large negative standard free energy value (-7.3 for each of the 2 terminal phosphates)
78
what are the 3 main sources of phosphate for ATP
1. oxidative phosphorylation
2. glycolysis (phosphoglycerate kinase and pyruvate kinase)
3. citric acid cycle (succinate thiokinase)
79
what 2 processes does oxidative phosphorylation couple
respiration and generation of ATP
80
how does the inner mitochondrial membrane differ from the outer
outer is permeable
inner is impermeable
81
what is needed due to the impermeability of the inner mitochondrial membrane
transporters
82
what is the function of cristae of the inner mitochondria membrane
increase SA
83
where does the electron transport chain occur in the cell
inner mitochondrial membrane
84
what is the role of the respiratory chain of the mitochondria
conversion of food energy to ATP
85
what is the basis of the ETC
high energy molecules (ex: glucose) are metabolized by redox reactions to yield CO2 and water
86
what do the metabolic intermediates of ETC reactions donate electrons to
NAD+ and FAD to form NADH and FADH2
87
as electrons are passed down the ETC, do they gain or lose free energy
lose
88
what is the energy lost by electrons as they are passed down the ETC used for
creating a proton gradient
89
what processes does oxidative phosphorylation couple
electron transport with ATP synthesis
90
what is the remainder of the free energy not trapped as ATP in the ETC used to drive
calcium transport into mitochondria
generate heat
91
how many complexes make up the inner mitochondrial membrane
5
92
what complexes of the inner mitochondrial membrane are used in the ETC
1-4
93
what are the 2 mobile electron carriers used in the ETC
co-enzyme Q
cytochrome c
94
what is the final e- acceptor of the ETC
molecular O2
95
what process accounts for the body's use of the greatest amount of oxygen
ETC
96
what is complex 5 of the inner mitochondrial membrane also called
ATP synthase
97
what complex of the inner mitochondrial membrane catalyzes ATP synthesis
5
98
what complexes of the inner mitochondrial membrane do e- pass through
1, 3, and 4
99
what is complex 1 of the inner mitochondrial membrane also called
NADH-Q oxidoreductase
100
what occurs in complex 1 of the inner mitochondrial membrane
e- are transferred from NADH to CoQ
101
what is CoQ also referred to as
ubiquinone
102
what is CoQH2 also known as
ubiquinol
103
what is complex 3 of the inner mitochondrial membrane also called
Q-cytochrome c oxidoreductase
104
what does complex 3 of the inner mitochondrial membrane do
pass e- from CoQ to cytochrome c
105
what is complex 4 of the inner mitochondrial membrane also called
cytochrome c oxidase
106
what does complex 4 of the inner mitochondrial membrane do
pass e- to O2, causing it to be reduced to H2O
107
what is complex 2 of the inner mitochondrial membrane also called
succinate-Q reductase
108
why are e- passed to Q through complex 2 instead of 1
the substrate (succinate) has a greater redox potential then NAD+/NADH
109
NADH carries a free protein. In the ETC, where is this proton transferred to
NADH dehydrogenase in complex 1
110
what complexes of the ETC contain iron-sulfur proteins
1, 2, 3
111
all members of the ETC are proteins with the exception of __ which is a __
coenzyme Q
lipid
112
coenzyme Q in the ETC accepts e- from what 2 complexes
1 and 2
113
coenzyme Q can accept e- from what enzyme in glycolysis
glycerophosphate dehydrogenase
114
coenzyme Q can accept e- from what enzyme in fatty acid oxidation
acyl CoA dehydrogenase
115
cytochromes contain a __ group with iron in a +__ (2 or 3) state
heme
3+
116
what complex of the ETC contains copper
4
117
what is the importance of copper in complex 4
required for splitting of O2
118
complex 4 contains how many heme and how many copper groups
2 heme
2 copper (CuA and CuB)
119
how many protons are pumped in complex 1 of the ETC
4
120
how many protons are pumped in complex 2 of the ETC
none
121
with the proton gradient of the ETC, the matrix side of the mitochondrial becomes positive or negative
negative
122
what does the chemiosmotic theory explain
free energy generated by the transport of electrons in ETC is used to produce ATP from ADP+Pi
123
what complexes of the ETC pump electrons
1, 3, 4
124
what drives the mechanism of ATP synthetase
proton motive force by electrochemical potential difference due to impermeability of inner mitochondrial membrane
125
what complexes act as a proton pump, creating a proton gradient across the membrane
I, III, IV
126
what does ATP synthase convert
ADP+Pi-->ATP
127
is ATP synthase embedded in the inner mitochondrial membrane or mobile
embedded
128
what are the 2 components of ATP synthase structure
F0
F1
129
where is F0 of ATP synthase located
inner mitochondrial membrane
130
where is F1 of ATP synthase located
mitochondrial matrix
131
what are the subunits of F1 of ATP synthase
3 alpha, 3 beta
132
what subunit of F1, alpha or beta, does ADP attach to
beta
133
what subunit of F1, alpha or beta, does ATP attach to
alpha
134
one rotation of ATP synthase produces how many ATP
3 (due to having 3 beta subunits)
135
what makes up the F0 subunit of ATP synthase
C protein subunits
136
what subunit is attached to the C protein subunits of ATP synthase directly
gamma
137
what subunit of ATP synthase, alpha beta or gamma, rotates
gamma
138
what does ATP synthase produce
ATP and heat
139
what is the function of heat produced by ATP synthase
maintain body temperature
140
what is the purpose of the ATP/ADP antiporter
as soon as ADP enters and produces ATP, ATP exits
141
what controls the rate of respiration (ETC/oxidative phosphorylation)
availability of ADP
142
what are 2 examples of substrate level phosphorylation
glycolytic reactions
citric acid cycle
143
for each mole of substrate oxidized by complexes I, III, and IV in respiratory chain (ETC) via NADH, how many moles of ATP are produced
2.5
144
for each mole of substrate oxidized by complexes II, III, and IV in respiratory chain (ETC) via FADH2, how many moles of ATP are produced
1.5
145
what allows molecular oxygen (O2) to act as an efficient final e- acceptor
high electronegativity
146
does each step of the ETC have a positive or negative delta G
negative
147
why is having a -delta G in each step of the ETC important
free energy is created and made available to to work and movement of protons
148
what do uncouplers do to the ETC
increase permeability of the membrane to ions/create a channel, interfering with the proton gradient as H+ is allowed to pass without going through ATP synthase (no ATP synthesis)
149
what is the main result of uncouplers of the ETC
energy is released as heat (excess of body heat)
150
what type of protein does thermogenin act as
uncoupling
151
is thermogenin a physiological or pathological uncoupler
physiological
152
where is thermogenin found
brown fat, especially in newborns
153
what is the function of themogenin
production of body heat
154
is 2,4-dinitrophenol a physiological or pathological uncoupler
pathological
155
what class does 2,4-dinitrophenol belong to
uncouplers
156
how does 2,4-dinitrophenol act
reduces electrochemical potential and short-circuits ATP synthase, causing energy to be released as heat rather than used to synthesize ATP
157
what is the result of 2,4-dinitrophenol in regards to heat production
hyperthermia
158
what class of proteins does high dose asprin and other salicylates act as in the ETC
uncouplers
159
oxidative phosphorylation uncoupling agents __ (increase or decrease) proton gradient and produce heat
decrease
160
electron transport inhibitors __ (increase or decrease) proton gradient
decrease
161
ATP synthase inhibitors __ (increase or decrease) proton gradient
increase
162
what class of antibiotic is oligomycin
macrolide
163
what is the effect of oligomycin
binds to F0 of ATP synthase, closing the H+ channel and preventing re-entry of protons
e- transport is stopped so no ATP or heat is produced
164
do uncoupling agents act on a specific complex
no
165
what complex do Rotenone and metformin act on
I
166
what complex do antimycin A and dimercaprol (BAL) act on
III
167
what complex does H2S, Azide, Cyanide, and CO act on
IV
168
what complex does oligomycin act on
ATP synthase (complex V)
169
what is Rotenone, which acts on complex I, also referred to as
fish poison
insecticide
170
what complex do barbiturates (Amytal) act on
I
171
what complex does malonate inhibit
II
172
how does cyanide stop ETC
binds Fe3+ and prevents conversion to Fe2+
*oxygen does not bind to Fe3+
173
how does CO stop ETC
binds Fe2+ and inhibits release of e- to oxygen
174
what is a common sign of cyanide and CO poisoning
cherry red colored skin (hypoxia)
175
how to identify cyanide exposure rather than CO
presence of smoke
soot in mouth and nose
odor of bitter almonds
176
what are 2 treatments for cyanide poisoning
nitrite (best)
hydroxocobalamin
177
how to identify CO poisoning rather than cyanide
obstructed exhaust
power outages
patients in a group/household with similar symptoms
178
how does atractyloside inhibit oxidative phosphorylation
inhibits transporter of ADP into ATP
179
what causes fatal infantile mitochondrial myopathy and renal dysfunction
absence of oxidoreductases of ETC (ATP synthesis) due to error in mitochondrial DNA
180
what causes MELAS (mitochondrial encephalopathy, lactic acidosis, and stroke)
complex I or complex IV deficiency due to mutation in mitochondrial DNA
181
how is mitochondrial DNA (mtDNA) inherited
through mother
182
what is the cause of Leber hereditary optic neuropathy
mutation in mtDNA
183
what is the cause of Leigh syndrome
a mutation in oxidative phosphorylation
184
carbohydrates are primarily composed of what 3 elements
C, O, H
185
how much energy does 1 gram of carbohydrate provide
4cal
186
what are the most abundant dietary source of energy
carbohydrates
187
what 2 cells are mostly dependent on carbohydrates are their energy source
brain cells
RBC
188
what is the energy storage form of carbohydrates
glycogen
189
what are amino sugars
a monosaccharide in which one or more hydroxyl groups are replaced by amino groups
190
chemically, carbohydrates are defines as ___ or ___
polyhydroxyl aldehydes or ketones
191
what are 2 examples of monosaccharides
glucose
fructose
192
what are 3 examples of dissacharides
lactose
sucrose
maltose
193
what are 3 examples of polysaccharides
starch
glycogen
cellulose
194
what is a monosaccharide
sugars that can't be hydrolyzed into simpler carbohydrates
(absorbable after digestion)
195
why is glucose identified as an aldose
it contains an aldehyde group
196
why is fructose identified as a ketose
it contains a ketone group
197
what are isomers
compounds with the same chemical formula but different structure
198
why are fructose, glucose, mannose, and galactose all considered isomers
they have the same chemical formula C6H12O6 but a different structure
199
what are epimeres
isomers that differ around only 1 specific carbon
200
what is an example of a C4 epimer
glucose and galactose
201
what is an example of a C2 epimer
glucose and mannose
202
what are stereoisomers
compounds with the same structural formula but different spatial arrangement
203
what are enantiomeres
structures which are mirror images of one another
204
what is an example of an enantiomer
D-glucose and L-glucose
205
what is considered the reference carbohydrate when looking at structural arrangement
glyceraldehyde
206
naturally occurring monosaccharides in humans are in L or D confirmation
D
207
what are anomers
structures that differ around carbon 1 (anomeric C)
208
__ and __ are used for anomers which are concerned with carbon __
alpha and beta
1
209
epimers are concerned with carbon __
2, 3, or 4
210
enantiomers are concerned with carbon __
5
211
what does dextrose mean
glucose in solution
212
why is glucose in solution referred to as dextrose
it is dextrorotary (based on rotation of light)
213
what bond links monosaccharides
glycosidic
214
what are disaccharides
sugars that yield 2 molecules of monosaccharide (same or different) following hydrolysis
215
lactose produces what 2 molecules following hydrolysis
glucose
galactose
216
sucrose produces what 2 molecules following hydrolysis
glucose
fructose
217
what is the storage form of carbohydrates in humans
glycogen
218
what are the 2 main components of starch
amylose
amylopectin
219
what bonds make up amylose
alpha 1,4 glycosidic, nonbranching
220
what bonds make up amylopectin
1, 4 and 1, 6 (branching)
221
what enzyme hydrolyzes starches
amylase
222
amylase acts on what type of glycosidic bonds
alpha
223
glycogen has a similar structure to amylose or amylopectin
amylopectin
224
what type of glycosidic bonds make up cellulose
beta 1,4
225
why can't cellulose be digested by animals
the bonds are beta, alpha amylase that animals (humans) have only breaks alpha bonds
226
what nutritional component is cellulose a major part of
fiber
227
what are 2 main functions of dietary fiber
decrease absorption of glucose and cholesterol from intestines
increase bulk of feces
228
what are the 2 primary sites of dietary carbohydrate digestion
mouth
lumen of intestine
229
what are the final products of carbohydrate digestion
glucose
galactose
fructose
230
what are the 2 isoenzymes of alpha amylase
salivary and pancreatic
231
why does alpha salivary amylase stop functioning in the stomach
due to acidic nature of the stomach
232
where are the enzymes located that break down the disaccharides of carbohydrate digestion
brush border in intestines
233
is insulin required with absorption of glucose
no
234
what type of transport is involved with absorption of carbohydrates (glucose)
secondary active transport
235
how does secondary active transport work in transport of glucose (carbohydrates)
Na+/glucose symport into cell
Na+ enters blood through Na+/K+ pump
glucose enters blood through GluT2 glucose uniporter (facilitative diffusion- through channel) on basal surface of intestinal cell
236
D-glucose and D-galactose are absorbed by ___ using ___
secondary active transport
SGLT (sodium-glucose/galactose co-transporter)
237
where is the SGLT transporter located
intestines
proximal convoluted tubule
238
the sodium ion dependent transport of glucose and galactose co-transports how many sodium ions for each glucose/galactose
2
239
the pumping of fructose into the cell uses what transport system
facilitative
240
what transporter is used with transport of fructose
GLUT5
241
where is GLUT2 located
liver, intestine, and pancreatic cells
242
where is GLUT4 located
muscle and fat cells
243
where is GLUT5 located
small intestine
244
what GLUT transporter is insulin reactive
4
245
dietary oligosaccharides enter the ___ and are fermented to form __
large intestines
gas
246
what can cause dissacharide degradation
intestinal diseases
malnutrition
drugs that injure mucosa of small intestines
247
what causes acquired enzyme deficiency
loss of brush border enzymes
248
what type of enzyme is lactase
brush border
249
what is primary lactose intolerance due to
genetically regulated reduction of lactase production
250
what is secondary (acquired) lactase intolerance due to
inflammation or infection
251
what are 2 cases that can cause secondary (acquired) lactose intolerance
celiac disease
giardiasis
252
what action is prevented by lactase deficiency
lactose-->glucose+galactose
253
without lactase, where is lactose transported from and to
from small intestine to large intestine
254
what is produced by lactose breakdown by bacteria in the large intestine without lactase
gas
255
what can be measured in the breath to determine lactase deficiency
H2
256
as a result of gas produced due to lactose breakdown by bacteria in the large intestine, what 4 symptoms may a patient experience
bloating
osmotic diarrhea
dehydration
flatulence (gas)
257
what is the main molecule in carbohydrate metabolism
glucose
258
why can glucose produce fructose and galactose
they are all epimers
259
what is metabolism
catabolic+anabolic pathways
260
proteins, carbohydrates, and fats are all broken down to give off the common product of ___
acetyl CoA
261
in glycolysis, 1 molecule of glucose produces __ molecules of pyruvate and __ ATP
2
2
262
what is the importance of glycolytic pathways
provides energy and intermediates for other metabolic pathways
263
what 2 cells require glycolysis for ATP production
brain cells
RBC
264
why do RBC need glycolysis to make ATP
they lack a mitochondria
265
where does glycolysis take place
cytosol
266
is glycolysis aerobic, anaerobic, or both
both
267
the ability of glycolysis to provide ATP in the absense of oxygen is especially important in ___ muscle because it allows the muscle to perform at high levels when oxygen supply is insufficient
skeletal
268
in low oxygen condition, pyruvate produced by glycolysis goes on to produce what
lactate
269
in normal oxygen condition, pyruvate produced by glycolysis goes on to what pathway
TCA
270
what are the 2 glucose transporters
Na+ dependent (SGLT)
Na+ independent (GLUT)
271
why is the first part of glycolysis called the investment phase
it uses ATP
272
glycolysis produces how many NADH per glucose molecule
2
273
what occurs during hexokinase reaction in glycolysis
irreversible phosphorylation of glucose, trapping glucose
274
is there conservation of free energy in the hexokinase reaction of glycolysis
yes
275
what is a requirement with the hexokinase reaction of glycolysis
Mg2+
276
does hexokinase have a high or low Km
low
277
why does hexokinase have a low Km
it has a high affinity for glucose at baseline
278
is hexokinase or glucokinase used during a fed state
glucokinase
279
is glucokinase or hexokinase used during a fasting state
hexokinase
280
is glucokinase or hexokinase used by the liver cells and beta cells of pancreas
glucokinase
281
is hexokinase or glucokinase used by RBC
hexokinase
282
why is glucokinase used instead of hexokinase during a fed state
there is a high glucose level that needs to be flooded away
283
what is the function of glucokinase in beta cells of the pancreas
acts as a glucose sensor determining threshold for insulin secretion
284
what is the function of glucokinase in liver cells
facilitate glucose phosphorylation during hyperglycemia
285
does glucokinase function when glucose levels are high or low
high
286
glucokinase functions especially after what type of macromolecule rich meal
carbohydrate
287
does glucokinase have a high or low Vmax
why
high
removal of flood of glucose post meal
288
what is the effect of glucokinase on hyperglycemia
minimizes hyperglycemia during absorptive period
289
what does a decrease in the activity of glucokinase lead to
maturity onset diabetes of the young type 2 (MODY2)
290
what inhibits hexokinase
glucose-6-phosphate
291
does glucokinase undergo feedback inhibition
no
292
what allows hexokinase to work at baseline glucose levels
low Km (high affinity)
293
is glucokinase or hexokinase induced by insulin
glucokinase
294
what does phosphofructokinase-1 of glycolysis catalyze
ATP dependent phosphorylation of fructose 6-phosphate to fructose 1,6-bisphosphate
295
what is the regulatory enzyme of glycolysis
phosphofructokinase-1
296
what are 2 inhibitors of PFK-1 in glycolysis
ATP
citrate
297
what are 3 activators of PFK-1 in glycolysis
fructose 2,6-bisphosphate
ADP/AMP (low ATP= low energy)
298
glycolysis produces how many ATP per glucose molecule
4
299
what 2 enzyme steps of glycolysis produce ATP by substrate level phosphorylation
phosphoglycerate kinase
pyruvate kinase
(*both kinases)
300
what enzyme step of glycolysis produces NADH
glyceraldehyde 3-phosphate dehydrogenase
301
how does arsenic poisoning work in relation to glycolysis
it inhibits glyceraldehyde 3-phosphate dehydrogenase by competing with Pi as a substrate
302
what are 2 inhibitors of glyceraldehyde 3-phosphate dehydrogenase
aresenic
iodoacetate
303
how does 1,3-bisphosphoglycerate of glycolysis generate ATP
substrate level phosphorylation
304
what enzyme of glycolysis is inhibited by fluoride
enolase
305
why is enolase inhibition by fluoride important in labs for blood glucose level checks
fluoride is added to blood to prevent glycolysis in order to receive an accurate blood glucose concentration
306
what 3 enzymes of glycolysis serve as control sites (regulation)
hexokinase
phosphofructokinase
pyruvate kinase
307
what molecule must be recognized for glycolysis to proceed
NAD+
308
in anaerobic respiration, pyruvate turns into what
lactate
309
in aerobic conditions, pyruvate turns into what
acetyl CoA
310
what respiration, anaerobic or aerobic, is required for oxidative phosphorylation
aerobic
311
in anaerobic respiration, pyruvate converts to lactate in order to make __ to continue glycolysis
NAD+
312
the formation of lactate is always occurring in what main blood cells. why
RBC
no mitohcondria
313
intense exercise of skeletal muscles results in elevated ___, favoring reduction of pyruvate to lactose
NADH:NAD+ ratio
NADH keeps building up= pyruvate to lactate
314
what enzyme converts pyruvate to lactate
lactate dehydrogenase
315
buildup of NADH encourages conversion of __ to __
pyruvate to lactate
316
what does buildup of lactate in muscle cause
muscle cramps
317
the extra lactate formed during intense exercise is converted to glucose by __ in the liver
gluconeogenesis
318
pyruvate to lactate requires __
NADH
319
lactate to pyruvate requires __
NAD+
320
when do we call glycolysis aerobic
when oxygen is required to oxidize NADH
321
when do we call glycolysis anaerobic
conversion of glucose to lactate
322
what muscle always oxidizes lactate to CO2 and H2O via TCA cycle
heart
323
what process is required to release energy from glycolysis
TCA cycle
324
in anaerobic glycolysis, there is a net production of __ ATP and __ NADH
2
0 (NADH is used to replenish NAD+)
325
in aerobic glycolysis, there is a net production of __ ATP and __ NADH
2
2
326
each NADH produces __ ATP
2.5/3
327
in RBC glycolysis, what step can be bypassed
substrate level phosphorylation ATP production step (phosphoglycerate kinase)
328
what stimulates the bypass of phosphoglycerate kinase in RBC
hypoxia
329
what is formed as a result of hypoxia in RBC in regards to glycolysis
2,3- BPG
330
in the presence of 2,3-BPG, oxyhemoglobin unloads __ (more or less) oxygen to tissues
more
331
what is 2,3-BPG formation called in RBC
BPG shunt
332
the BPG shunt occurs in what
RBC
333
transfused blood has a higher or lower 2,3-BPG level
lower
334
what is the effect of lower 2,3-BPG in transfused blood
less efficient at delivering oxygen to tissue
334
what is the primary anabolic hormone (fed state)
insulin
335
what is the primary catabolic hormone (fasting state)
glucagon
336
insulin and glucagon hormone regulation are involved in what 3 enzymes of glycolysis
glucokinase/hexokinase
phosphofructokinase
pyruvate kinase
337
what is hemolysis
high lysis of RBC
338
what enzyme of glycolysis deficiency can lead to hemolytic anemia
pyruvate kinase deficiency
339
what are 2 reasons RBC require ATP
to maintain biconcave, flexible shape of the cell
(if no ATP= RBC get trapped in narrow capillaries, leads to lysis)
to maintain Na+/K ATPase function (loss of function leads to osmotic fragility= RBC lysis)
340
how is NADH (reducing equivalent) at NADH step of glycolysis transferred to mitochondria from cytosol
glycerophosphate shuttle and malate shuttle
341
what is the result of the glycerophosphate shuttle in regards to ATP production
since glycerol-3-phosphate dehydrogenase of the mitochondria is linked to a flavoprotein instead of NAD as it is in the cytosol, 1.5 mole of ATP are formed per atom instead of 2.5
*NADH-->NAD+ gives 2.5/3 ATP
FAD+-->FADH2 gives 1.5/2 ATP
342
the glycerophosphate shuttle is present in __ but absent in __
brain
heart
343
is the phosphoglycerate or malate shuttle more universal
malate
344
what enzyme is used in the glycerophosphate shuttle
glycerol-3-phosphate dehydrogenase
345
the glycerophosphate shuttle is linked with what molecule
FAD
346
TCA cycle takes place in ___
mitochondria
347
what is the final common pathway for the oxidation of fuel molecules
TCA cycle
348
carbohydrates, protein, and lipids become __ to enter the __ cycle
acetyl CoA
TCA
349
what enzyme links glycolysis to TCA cycle
pyruvate dehydrogenase
350
pyruvate is transported into the mitochondria by a ___
protein symporter
351
pyruvate goes through __ to become acetyl CoA
oxidative decarboxylation
352
pyruvate is converted to acetyl CoA by what complex
pyruvate dehydrogenase complex
353
pyruvate dehydrogenase complex is found where
mitochondria
354
what are the 2 regulatory enzymes of the pyruvate dehydrogenase complex
pyruvate dehydrogenase kinase
pyruvate dehydrogenase phosphatase
355
in pyruvate dehydrogenase complex, e- is transferred from FAD to NAD+. why
e- transfer potential of FAD is increased by its association with the enzyme
356
what 3 molecules inhibit pyruvate dehydrogenase complex
acetyl CoA
NADH
ATP
357
if an enzyme is under the effect on glucagon, it is active in phosphorylated or dephosphorylated state
phosphorylated (kinase enzymes)
358
if an enzyme is under the effect on insulin, it is active in phosphorylated or dephosphorylated state
dephosphorylated (phosphatase enzymes)
359
what are the 5 coenzymes of pyruvate dehydrogenase complex
thymine, lipoic acid, CoA, FAD, NAD
360
what is the affect of calcium on the pyruvate dehydrogenase complex
calcium released during muscle contraction leads to dephosphorylation and activation of pyruvate dehydrogenase complex
361
what can cause lactic acidosis
pyruvate dehydrogenase complex deficiency
362
what is the treatment of pyruvate dehydrogenase complex deficiency
no treatment, remove carbohydrates from diet, supplementation with thiamine
(pyruvate dehydrogenase complex coenzyme)
363
what causes Leigh syndrome
mitochondrial ATP enzyme defects
(defect in enzyme of oxidative phosphorylation, mutation in genes that code for pyruvate dehydrogenase complex, or ATP synthase)
364
how many carbons enter the TCA cycle as acetyl CoA
2
365
acetyl CoA entering TCA cycle are balanced by 2 __ exiting
CO2
366
how many carbons does acetyl CoA have
2
367
in the TCA cycle the first step is acetyl CoA--->citrate. this is catalyzed by
citrate synthase
368
the first product of the TCA cycle, citrate, is inhibited by what
citrate
369
what are the 3 fates of citrate
go into TCA cycle
go to cytosol and activate acetyl CoA carboxylase for FA synthesis
inhibit phosphofructokinase-1 of glycolysis
370
where is the site of the TCA cycle
mitochondria matrix
371
citrate is isomerized to isocitrate by what enzyme
aconitase
372
is aconitase an Fe-S proteins
yes
373
isocitrate dehydrogenase releases what 2 products
CO2 and NADH
374
what are the 2 rate limiting steps of the TCA cycle
isocitrate dehydrogenase
alpha-ketoglutarate dehydrogenase
375
isocitrate dehydrogenase is activated by
ADP
Ca2+
376
isocitrate dehydrogenase is inhibited by __ and ___
ATP
NADH
377
what 2 enzymes of TCA release CO2
isocitrate dehydrogenase
alpha-ketoglutarate dehydrogenase
378
what is an energy rich compound produced during TCA cycle
succinyl CoA
379
the cleavage of thioester bond of succinyl CoA is coupled to phosphorylation of what
GDP
380
what are the 2 major concepts of succinyl CoA synthetase (succinate thiokinase)
substrate level phosphorylation
GDP-->GTP
381
what is the substrate level phosphorylation enzyme of TCA cycle
succinyl CoA synthetase (succinate thiokinase)
382
what is the only enzyme of the TCA cycle that is embedded in the inner mitochondrial membrane
succinate dehydrogenase (complex II)
383
what enzyme of the TCA cycle is an FAD containing enzyme
succinate dehydrogenase
384
what is the enzyme that allows the link between the TCA cycle and ATP formation
succinate dehydrogenase
385
if you see FMN or FAD, what is involved
riboflavin
386
FMN is a component of what ETC complex while FAD is a component of what ETC complex
FMN- complex I
FAD- complex II
387
malate dehydrogenase releases what
NADH
388
how many ATP are produced from one turn of TCA cycle
10/12
(3 NADH, 1 FADH2, 1 GTP)
389
what does it mean to say the TCA cycle is amphibolic
intermediates can come in and out
(it is both an oxidative and synthetic process)
390
what does it mean to say a reaction is anaplerotic in the TCA cycle
generate intermediates
391
can acetyl CoA convert back to glucose
no
392
the coenzyme thiamine pyrophosphate of the TCA cycle is derived from what
B1/thiamine
393
the coenzymes lipoic acid and CoA of the TCA cycle are derived from what
B5/pantotheic acid
394
the coenzyme flavin adenine dinucleotide (FAD) of the TCA cycle is derived from what
B2/riboflavin
395
the coenzyme nicotinamide adenine dinucleotide (NAD+) of the TCA cycle is derived from what
B3/niacin
396
the complete split of glucose by aerobic respiration produces how many ATP
38 (or 32)
397
the complete split of glucose by anaerobic respiration produces how many ATP
2
398
why can't acetyl CoA form glucose
acetyl CoA is released as CO2 through oxidative decarboxylation reaction
399
what is beriberi
thiamine deficiency leads to low transketolase activity of RBC
400
arsenic poisoning is due mostly to inhibition of enzymes that require __
lipoic acid (pyruvate dehydrogenase complex and TCA)
401
arsenic affects what 3 spots of the TCA cycle
fluoroacetate
arsenate
malonate
402
what is this only source of fuel for skeletal muscle under anaerobic conditions
glucose
403
what does gluconeogenesis help clear
lactate and glycerol
404
what is the first source of blood glucose in a fasting state
liver glycogen
405
what is gluconeogenesis
making glucose from non-carbohydrate sources
406
what are the 5 substrates for gluconeogenesis
lactate
pyruvate
glucogenic AA
propionate
glycerol
407
where is the location of gluconeogenesis
cytosol
408
during an overnight fast, which organs does gluconeogenesis occur in
liver (mostly, 90%)
kidney (10%)
409
during a prolonged fast, which organ is the main organ of gluconeogenesis
kidney
410
the 3 reversible steps of glycolysis are catalyzed by what 3 enzymes
hexokinase
phosphofructokinase
pyruvate kinase
411
what is required as a cofactor with pyruvate carboxylase in gluconeogenesis
biotin
412
where is pyruvate carboxylase of gluconeogenesis located
mitochondria
413
what activates pyruvate carboxylase
acetyl CoA
414
what is the rate limiting steps of gluconeogenesis
pyruvate carboxylase
phosphoenolpyruvate carboxykinase
fructose 1, 6-bisphosphatase
glucose 6-phosphate
415
if there is a carboxylase enzyme, what cofactor is always involved
biotin
416
what is a source of biotin deficiency
raw egg whites
*contains avidin which binds biotin and prevents it's absorption
417
in what state is pyruvate carboxylase activated by acetyl CoA
fasting
418
where is oxaloacetate of gluconeogenesis located
mitochondrial matrix
419
how does oxaloacetate, which is synthesized in the mitochondrial matrix, reach the cytosol to be converted to phosphoenolpyruvate
oxaloacetate is converted to malate through malate dehydrogenase
malate reaches the cytosol
malate is converted back to oxaloacetate by malate dehydrogenase
420
what are the 2 regulatory enzymes of gluconeogenesis
pyruvate carboxylase
fructose 1,6-bisphosphate
421
what enzyme converts glucose 6-phosphate to glucose in gluconeogenesis
glucose 6-phosphatase
422
in what organs is glucose 6-phosphatase, needed to convert glucose 6-phosphate to glucose, mostly located
liver
kidneys
423
in what organelle is glucose 6-phosphatase, needed to convert glucose 6-phosphate to glucose, located
endoplasmic reticulum
424
where in the body is glucose 6-phosphatase, an enzyme of gluconeogenesis, absent
muscle
425
what supplies the ATP required for gluconeogenesis
fatty acid oxidation
