BIOCHEMISTRY- Processes Videos Flashcards
(176 cards)
1
Q
From where is energy extracted?
A
From food via oxidation
2
Q
Which are the processes of energy extracted from food?
A
- Hydrolyzed in the GI tract to a diverse set of monomeric building blocks
- Building blocks are degraded to a common metabolic intermediate, acetyl CoA
- Citric acid cycle oxidizes acetyl CoA to CO2
- Extraction of energy from food is oxidative phosphorylation in which the energy of NADH and FADH2 is released via the ETC and used by an ATP synthase to produce ATP
3
Q
Which cycle oxidizes acetyl CoA to CO2?
A
Citric acid cycle
4
Q
What is increased every time metabolism is increased?
A
CO2
5
Q
What is the first substrate of TCA cycle?
A
Acetyl CoA
6
Q
Which are the products of TCA cycle?
A
2 CO2, 3 NADH and FADH2
7
Q
What activates NADH and FADH?
A
Dehydrogenases
8
Q
What do NADH and FADH2 produce?
A
Electrons
9
Q
What happens to the electrons produced by NADH and FADH?
A
The electron transporter chain take them
10
Q
Where does Electron Transporter chain work?
A
In the inner mitochondrial membrane
11
Q
Who is the acceptor of electrons?
A
O2
12
Q
Which is the most common cause of damage tissue?
A
Hypoxia–> Decrease the production of energy
13
Q
Three main causes of hypoxia
A
Vessels
Heart/lung
Red blood cells
14
Q
Which enzyme derives the energy of the electron transport chain?
A
ATP synthase
15
Q
What is the function of ATP synthase?
A
Derives the energy of the E;ectron Transport chain to make ATP
16
Q
Which is the process of how ATP is produced by ATP synthase?
A
By oxidative phosphorylation
17
Q
What are the main sources of Acetyl CoA?
A
Carbohydrate → Glucose → Pyruvate
Fat → Fatty acids
Protein → Aminoacids
18
Q
Which is the process where GLucose becomes Pyruvate?
A
Glycolysis
19
Q
What else is produce in Glycolysis?
A
ATP (in the abscense of Oxygen)
20
Q
From where is ATP produce in the abscense of Oxygen?
A
From anaerobic Glycolysis
Substrate Level phosphorylation
21
Q
Which enzyme is required from pyruvate conversion to Acetyl CoA?
A
PDH
22
Q
When do Carbohydrates produce Acetyl CoA?
A
After a meal
23
Q
When do Fat produce Acetyl CoA?
A
Between meals
24
Q
Process that leads from fatty acids to Acetyl CoA?
A
β oxidation
25
Which hormone is present after a meal?
Insulin
26
Which hormones are present between meals?
Glucagon, Cortisol, epinephrine
27
Who are the main source of Acetyl CoA when you are between meals?
Fatty acids
28
Which is the only organ that uses Fatty acids after a meal?
Heart
29
What is GLycogen?
Taking a lot of glucose and forming a large chain of glucose
| Storage form of glucose
30
Which hormone forms glycogen?
Insulin
31
What controls the formation of glycogen?
Insulin
| High levels of ATP from burning sugar
32
Which is the starting point of Gluconeogenesis?
In the liver starting from pyruvate
33
From where can we get pyruvate?
From aminoacids, alanine by alanine transmaminase
| From lactate coming from Red blood cells by cori cycle
34
Which organ produces Ketone bodies?
Liver
35
Which organs use ketone bodies to make Acetyl CoA?
Heart, kidneys
36
Once ATP is high, what is the effect of insulin?
Make glycogen or make fat
37
Once ATP is high, what is the effect of Glucagon?
Make ketones
Make glucose thorugh gluconeogenesis
Release glucose from glycogen through gluconeogenesis
38
Which food are high carb meals?
Starch, sucrose, lactose
39
After digestion of starch, sucrose and lactose by amylase... What are the results?
Maltose, isomaltose, sucrose, lactose
40
Who breaks maltose, ismolatose, sucrose and lactose?
Brush border disaccharidases
41
What are the products of brush border disaccharidases?
Glc, Gal, Fru (Monosacharides)
42
Which forms of carbohydrates can't be absorbed?
Disacharides, they have to be monosacharides
43
How are monosacharides absorbed in the intestinal lumen?
By active transport by Na+/ Gl symporter
44
Which are the insulin dependent tissues?
Liver, adipocytes anb muscle
45
Which GLUT is very associated with insulin?
GLUT 4
46
What is the effect of increased insulin related to GLUT 4?
Increases the number of plasma membrane GLUT 4 transporters
47
Where are GLUT 4 found?
In muscle and adipose tissue
48
What is the effect of GLUT 4?
Glucose removal out of Blood
49
How are GLUT 4 made?
Cytoplasmic vesicles with membrane bound GLUT 4 transporters
50
Which is the sign for GLUT 4?
Insulin effect, opening the vesicle to free GLUT 4
51
How is responsable of opening the vesicle who frees GLUT?
Insulin binds to the receptor → All the systems activated → PI3 kinase → Open vesicles
52
What is the effect of insulin in the adipose tissue?
↑ LPL (lipoproteinlipase) → break down tryglycerides and Fatty acids
53
Why do we require LPL?
Because Tryglycerides can't go into the membrane; so membrane they break down to fatty acids pass thorugh the membrane and once again inside the adipocyte become tryglyceride and stored
54
Where do we find GLUT 1?
Most tissues (brain, red cells)
55
Where do we find GLUT-2?
Liver, Pancreatic β cells
56
Where do we find GLUT 3?
Most tissues
57
Where do we find GLUT 4?
Skeletal muscle
| Adipose tissue
58
Which GLUT manage basal uptake of glucose?
GLUT-1 and GLUT-3
59
What is the function of GLUT-2?
Uptake and release of glucose by the liver; β cell glucose sensor
60
It's function is insulin stimulated glucose uptake; stimualted by exercise in skeletal muslce
GLUT 4
61
Which are the normal glucose concentration?
4-6 mM (72-110 mg/ dL)
62
Which are the GLUT that transport GLucose at a constant rate regardless of blood GLucose?
GLUT 1 and GLUT 3 (1mM value)
63
km glucose levels of GLUT 2
15 mM
64
Which GLUT serves as a glucose sensor in the pancreas?
GLUT 2 in β pancreatic cells
65
What is the process of glucose once it gets to the pancreas?
1. Enter β cell by GLUT 2
2. GLucokinase phosphorylate GLucose
3. Glucose phosphate enters glycolysis in Mitochondrion
4. Oxidation is done making a lot of ATP
66
What is the effect of high ATP levels in β pancreatic cells?
Closes K ATP channel → Decreased membrane depolarization → Opens Ca2+ channel (calcium enters pancreatic cells) → Activates ATPases → COnversion of proinsulin to insulin → insulin is released out of the pancreas into blood stream
67
How is insulin secretion?
Biphasic:
1. Preformed insulin (occurs within 10-15 minutes)
2. Newly synthesized insulin (last up to 2 hours)
68
Which enzyme converts Glucose to Glucose 6 P?
Hexokinase
69
Who regulates Hexokinase?
The product which is Glucose 6P
70
Which enzyme is found in the liver and has the same activity as Hexokinase?
Glucokinase
71
What is the function of Kinase?
Phosphorylate the product = ATP → ADP
72
Who regulates Glucokinase?
Insulin
73
Which is one of the most important enzymes in glycolysis?
PFK-1 (Phosphofructokinase- 1 )
74
What is the effect of PFK 1?
Conversion of Fructose 6P to Fructose 1,6 bis P
75
What is the importance of PFK-1?
Is highly regulated by a lot of things but the main ones: AMP (+), ATP (-) and Citrate (remember this last one is pruduced during Kreb cycle)
76
From all the processes of glycolysis, how do we get to Pyruvate?
From Phosphoenolpyruvate, thanks to Pyruvate kinase effect it becomes pyruvate
77
Which enzyme makes Acetyl CoA from Pyruvate?
Pyruvate dehydrogenase
78
Which are the main pathway that Acetyl CoA can cause?
TCA of Fatty acid synthesis
79
Type of enzyme defect found with Pyruvate defect?
Partial defect
80
Pathologies associated with Pyruvate kinase
Hemolytic anemia
Increased BPG
NO HEINZ BODIES
81
What is the function of Pyruvate kinase?
It catalyzes the transfer of a phosphate group from phosphoenolpyruvate (PEP) to ADP, yielding one molecule of pyruvate and one molecule of ATP
82
Second most common cause of Hemolytic anemia
Pyruvate kinase deficiency
83
Which are the only metabolic pathway remain in Erythrocytes?
Glycolysis
| Hexomonophosphate shunt
84
Why do RBC require GLycolysis?
Because they require energy for the pumps of channels in the memebrane to maintain a gradient, of not the cells shape is lost which leads to hemolytic anemia
85
Why do erythrocytes require NADH?
Antioxidant
Conversion of Methemoglobin to hemoglobin. Remember that NADH gives electrons and those electrons are required for the conversion of Fe+3 (methemoglobin) to Fe2+ (normal hemoglobin)
86
What is the effect of 2,3 BPG in the RBC?
↓ O2 affinity for Hb
| ↑ O2 unloading
87
What is found in erythrocytes structure in G6P deficiency?
Heinz bodies
88
Most common cause of Hemolytic anemia
G6P deficiency
89
What are the effects after high carb meal?
↑ ATP
↓ PFK-1
↓ GLycolysis
90
Where is PFK-2 6-P found?
Liver
91
What is the result of PFK-2?
Fructose 6P → Fructore 2,6 P
92
What is the function of PFK-2?
Force PFK-1 to work in the liver to conclude forming fatty acids
93
Who regulates positively PFK-2?
Insulin
94
Who turns off PFK-2?
Glucagon
95
How many ATP are generated in anaerobic glycolysis?
2
96
Where does 2,3 BPG bind in the RBC?
To β subunits
97
?What is the function of 2,3 BPG
Kick out the oxygen of the erythrocyte in order to oxygenate tissues
98
Does 2,3 BPG bind to HbF?
NO
99
What is the function of Lactase?
Convert Lactose to Glucose and Galactose
100
Where does Galactose enters?
Liver and Brain
101
Which enzyme catabolizes Galactose?
Galactose kinase and the product is Galactose 1-P in the liver and the brain
102
What enzyme is required for galactose1-P to become Glucose 1-P?
Gal 1- P Uridyl transferase
103
Which enzymes might be deficient in Galactosemia?
Galactokinase
| Gal 1- P Uridyl transferase
104
Clinical findings of Glacatokinase deficiency
Cataracts early in life
105
Clinical findings of Gal 1- P Uridyl transferase deficiency
```
Cataracts early in life
Vomiting, diarrhea after lactose ingestion
Letharghy
Liver damage, hyperbilirubinemia
Mental retardation
```
106
If galactose accumulate where does it go?
To the lens
107
Once galactose goes to the lens what happens?
Aldose reductase catabolizes it, becoming Galactiol (Polyol)
108
What is the effect of Galactiol in the lens?
It gets trapped causing cataracts and swelling
109
What explains cataracts in diabetics?
Glucose accumulate in the lens becoming sorbitol thanks to aldolase reductase
110
What are the components of Sucrose?
Glucose+ Fructose catalized by sucrase
111
Where does Fructose go?
Liver and kidney
112
In fructose metabolism which are the main enzymes?
Fructokinase and aldolase B
113
What does Fructokinase catalize?
Fructose to Fructose 1-P (phosphorylates)
114
What does Aldolase B catalize?
Fructose 1P → Glyceraldehyde or DHAP
115
Alternative name for fructokinase deficiency
Essential fructosuria
116
Findings of Aldolase B deficiency
```
Lethargy, vomiting
Liver damage, hyperbilirubinemia
Hypoglycemia
Hyperuricemia
Renal proximal tubule defect (Fanconi)
```
117
Alternative name for Aldolase B deficiency
Hereditary Fructose Intolerance
118
Which enzyme catalizes the conversion of Pyruvate to Acetyl CoA?
Pyruvate dehydrogenase
119
Where is Pyruvate dehydrogenase located?
In the Mitochondria
120
What does Pyruvate dehydrogenase do?
Two paths:
Take the electrons of Pyruvate; from NAD form NADH and generate 3 ATP and CO2
Becomes Acetyl CoA enters TCA cycle and form more ATP
121
Which is the main characteristic of Pyruvate Dehydrogenase?
Highly regulated
122
Who regulates Pyruvate dehydrogenase?
Acetyl CoA (the product- negatively)
123
What does Pyruvate Dehydrogenase need to work?
```
Tender Loving Care For Nancy
Thiamine pyrophosphate (TPP) form vitamin Thiamine
Lipioc acid
Coenzyme A (CoA) from panthothenic
FAD (H2) from riboflavin
NAD (H) from niacin
```
124
Which enzymes require the mnemonic "Tender Loving Care For Nancy"?
Pyruvate Dehydrogenase
α ketoglutarate
Branched-chain ketoacid dehydrogenase
125
Why can IV glucose solution kill alcoholic patients?
Because of Lactic acidosis
126
Why IV solution cause lactic acidosis in alcoholic patients?
Thiamine deficiency → Bad function of Pyruvate dehydrogenase → Pyruvate not becoming Acetyl CoA → Pyruvate accummulate out of mitochoncria in the cytoplasm → Lactic dehydrogenase start working on accumulated Pyruvate → Lactic Acidosis → Dead
127
How many ATPs are generated by Acetyl CoA in Kreb Cycle?
12 ATP per Acetyl CoA, but glucose generate 2 acetyl CoA so 24 ATP total
128
In TCA cycle what is the function of α ketoglutarate dehydrogenase?
Catabolize α ketoglutarate to Succinyl CoA producing CO2 and NADPH
129
What does α ketoglutarate need to work?
```
Tender Loving Care For Nancy
Thiamine pyrophosphate (TPP) form vitamin Thiamine
Lipioc acid
Coenzyme A (CoA) from panthothenic
FAD (H2) from riboflavin
NAD (H) from niacin
```
130
Which is the most important enzyme of Kreb cycle?
Isocitrate dehydrogenase
131
What regulates Isocitrate dehydrogenase?
ATP, NADH (low ATP, NADH → ↑ Isocitrate dehydrogenase; High ATP, NADH → ↓ Isocitrate dehydrogenase)
132
Once Isocitrate dehydrogenase is inhibited what is the effect?
Isocitrate accummulates in the mitochondria → Citrate spills out to cytoplasm → Citrate accumulation on cytoplasm → Inhibition of PFK 1 (Top regulator of glycolysis)
133
Alternative names for Coenzyme Q
Ubiquinone
CoQ
CoQ10
134
What is Coenzyme Q?
A lipid
135
In oxidative Phosphorylation pathway in electron chain reaction which are the bypass reaction for Ubiquinone?
Succinate dehydrogenase FADH2 Complex II (krebs cycle)
Fatty Acyl CoA dehydrogenase FADH2 (β oxidation)
GLycerol-P shuttle FADH2 (Glycolysis)
NADH dehydrogenase Comple I
136
Which enzyme does β oxidation?
Fatty Acyl CoA dehydrogenase FADH2
137
During Oxidative phosphorylation on the mitochondria which drugs inhibit NADH dehydrogenase Complex I?
```
Barbiturates
Rotenone (an insecticide)
```
138
How do Barbiturates and Rotenone inhibit the production of ATP?
Stop electron flow from NADH dehydrogenase Complex I to Coenzyme Q (Ubiquinone)
139
In oxidative Phosphorylation who affects complex IV cytochrome oxidase?
Cyanide
140
How does cyanide kill?
Because it binds Fe in its Fe3+ form in Complex IV, then when electrons come down in electron transport when they get in complex IV, electrons can't go to complex IV in the Fe3+ because there is cyanide, so electrons back up (electrons flow stop) so no ATP is made
141
What are the antidotes for cyanide poisoning?
1) Nitrite
| 2) Thiosulfate
142
How does Nitrite work as antidote for Cyanide poisoning?
1) Nitrite (oxidative agent, removes electrons) → making Methemoglobin
Hb (Fe2+) + Nitrite → Hb (Fe3+)
Once Methemoglobin is formed (thanks to nitrite), cyanide will look for Fe3+ and bind to it, instead of binding to the Fe3+ of the Complex IV
143
How does Thiosulfate work as antidote for Cyanide poisoning?
Will convert cyanide to thiocyanate (less toxic)
144
What does CO bind to?
To Fe2+ form
145
How does CO affect Complex IV?
Because it binds to Fe2+ form of the complex IV, preventing the electron to bind to Fe2+, so no ATP generated
146
What is the function of the F0 channel?
Transportation of protons to the F1 compartment in the phosphorylation of ADP to ATP
147
How does Oligomycin inhibit ATP formation?
By inhibiting F0 channel, so no proton transportation to F1 compartment, so no ADP Phosphorylation to ATP
148
Which drug inhibits F0 channel in Mitochondrioa in ATP formation?
Olygomycin
149
Which antiporter system moves ATP out of the mitochondrioa?
ATP/ ADP translocase
150
What is the function of ATP/ADP translocase?
Works as Antiporter moving ATP out of the mitochondria and introducing ADP once again into the mitochondria
151
Who regulates Oxidative phosphorylation?
ADP (controls rate- respiratory control)
152
In the oxidative phosphorylation process who works as an uncoupler?
2,4 DNP
153
What is the effect of 2,4 DNP?
Weak base which allows H+ back in matrix, so no ATP production, because protons do not reach F1 compartment
154
Which drugs are consider uncouplers?
Aspirin (High dose)
| Thermogenin
155
How is glycogen formed?
By α 1, 4 glucose attachment to another α 1,4 glucose, thanks to glycogen synthase
After 12-13 glucose residues, a branching enzyme make it α 1,6 glucose linkage
156
Who positively regulates glycogen synthase? Where?
Insulin, in the liver and muscle
157
Who turns off glycogen synthase?
Glucagon
158
Which enzyme breaks down Glycogen in order to form Glucose 1 P?
Glycogen Phosphorylase
159
What is the function of Glycogen Phosphorylase?
Adds inorganic phosphate to cleave sugar bonds converting Glycogen to Glucose 1-P
160
Which are the two most important phosphorylases?
Glycogen phosphorylase
| Purin Nucleoside Phosphorylase
161
Which is the accesory enzyme that helps Glycogen Phosphorylase?
Debranching enzyme, which debranch the α 1,6 Glucose, depolarizing
162
Who regulates Glycogen Phosphorylase?
Glucagon (Liver)
Epinephrine (liver, muscle)
AMP (muscle)
163
Who inhibits or dephosphorylates Glycogen Phosphorylase?
Insulin
164
Which enzyme catabolizes the conversion of Glucose 6 P to Glucose?
Glucose 6 Phosphatase
165
Where can we find glucose 6 Phosphatase?
In the liver
166
In the muscle what happens to GLucose 6 P?
Enters glycolysis, becoming pyruvate in the end generating Lactate or ATP, CO2 + H20
167
Where is glycolysis made?
In the muscle
168
What is purpose of glucose 6- Phosphatase found only in the liver?
Because it maintains glucose in the body
169
Glycogen storage diseases
von Gierke
Pompe
Cori disease
Andersen disease
170
Which pathology is associated to GLucose 6 phosphatase deficiency?
von Gierke disease (GLycogen storage disease)
171
Cardinal clinical features of von Gierke disease
Severe hypoglycemia, lactic acidosis, hepatomegaly, hyperlipidemia, hyperuricemia, short stature, doll like facies, protruding abdomen, emanciated extremities
172
How is glycogen synthesis in von Gierke disease?
Normal
173
Deficient enzyme in Pompe disease
Lysosomal α 1,4 glucosidase
174
Cardinal clinical features Pompe disease
Cardiomegaly, muscle weakness, death by 2 year
175
How is glycogen synthesis in Pompe disease?
Glycogen like material in inclusions bodies
176
Deficient enzyme in Cori disease
Glycogen debranching enzyme
