Biochemistry final Flashcards
(400 cards)
1
Q
Where is the high energy bonds in Phosphocreatine used?
A
Nerve cells and muscle cells for storage
2
Q
Creatine reaction
A
Phosphocreatine + ADP = ATP + Creatine
3
Q
Enzyme of 1st step in Creatine synthesis (in kidney)
A
Arginine- Glycine- Transamidinase
4
Q
Enzyme of 2nd step in Creatine synthesis (in liver)
A
Guanidinoacetate-methyltransferase
5
Q
Thioester bond forms between…
A
A carbocylic acid and a thiol (SH) group
6
Q
Enzyme of Folic acid/ Vit.B9 synthesis
A
Dihydrofolate reductase
7
Q
Dihydrofolate (FH2) reductase synthesis can be inhibited by antivitamins. Which ones?
A
Aminopterine, Ametopterine and Trinutoprim
8
Q
Biochemical role of Vit.B9/ Folic acid
A
To transfer carbon fragments. Carbon group is carried on N5, N10 or a bridge between them.
9
Q
Deficiency of Folic acid/ Vit.B9
A
Slow cell division, Slow growth, this will cause low RBC amount. Macrocytic hyperchrom anaemia
10
Q
Which receptor binds to Insulin?
A
Receptor tyrosine kinase
11
Q
Which enzyme is activated by Glucagon in the signal pathway?
A
Adenylate cyclase
12
Q
Where is Glycogen stored?
A
Liver and muscle
13
Q
Biochemical role of Vit. E/ Tocoferol
A
Stop free radical attack in biological membranes by antioxidant activity.
14
Q
ROS (reactive oxygen species) free radicals:
A
Superoxide anion radical, Hydroxyl radical, Peroxyl radical
15
Q
ROS (reactive oxygen species) non-free radicals:
A
Hydrogen peroxide produced på oxidase
16
Q
RNS (reactive nitrogen species) free radicals:
A
Nitrogen oxide, Oxidized NO=smoke, fog
17
Q
RCS (reactive chloride species) non free radicals:
A
Hipochloric acid (HOCl), produced by neutrophyls by myeloperoxidase enzyme during
18
Q
Location of Glycolysis
A
Cytoplasm of each cell, muscle and RBC
19
Q
Which steps in Glycolysis produces energy?
A
Glyceraldehyde-3-P –> 1,3biP-glycerate in form of NADH-H+,
1,3-biP-glycerate –> 3-phosphoglycerate in form of ATP,
and Phosphoenolpyruvate –> Pyruvate in form of 2 ATP
20
Q
Deficiency of vitamins in general:
A
Decrease enzymatic processes, disturb metabolic processes and pathological state may develop
21
Q
Name some fat soluble vitamins:
A
Retinol (Vit.A), Calciferol (Vit.D), Tocoferol (Vit.E) and Phylloquinone (Vit.K)
22
Q
Name some water soluble vitamins:
A
Vit. B&C (Thiamine/B1, Biotin, Riboflavin/B2, Pyroxidine/B6)
23
Q
Role of fat soluble vitamins
A
Role in bile, role as transporters, in storage
24
Q
Role of water soluble vitamins
A
Role as cofactors/prostetic groups
25
Where is gluconeogenesis located?
Cytoplasm in liver (kidney and intestines), but pyruvate--> OAC happens in mitochondria
26
Where is gluconeogenesis important?
Brain, testes, erythrocytes and kidney
27
Energy balance for Gluconeogenesis
If the product is glucose: -6 ATP is used
| If the product is Glycogen: -7 ATP is used
28
Enzyme needed for OAC--> Phosphoenolpyruvate
Phosphoenolpyruvate carboxykinase
29
Enzyme needed for Pyruvate--> OAC
Pyruvate carboxylase (regulator enzyme)
30
Which lipotropic factors do we have?
Choline and Inositol
31
Synthesis of Choline happens in...?
Liver in the hepatocytes:
| Serine --> ethanolamine --> choline
32
Sources of Choline
egg yolk, soya, peanuts, wheat germ
33
Deficiency of Choline
Fatty liver, haemorrhagic kidney degeneration, less AcCoA, slow growth
34
Source of Inositol
yeast, grains (diet contains inositol mainly in Phytate form
35
synthesis of Inositol happens in...?
Liver (and kidney)
36
Deficiency of Inositol
mostly in experimental conditions: fatty liver, slow growth
37
Main role of AcCoA
to deliver the acetyl-group to the TCA cycle to be oxidized for energy
38
What is needed in the complex of oxidation of Pyruvate to AcCoA
The enzyme is pyruvate dehydrogenase. We also need: Thiamine pyrophosphate (TPP) to remove CO2, Lopoic acid to add HS-CoA, NAD+ and FAD which removes H+ by oxidation.
39
Location of Glycerol phosphate shuttle
skeletal muscle and brain
40
Concept of Glycerol phosphate shuttle:
NADH+H+ needs to be transported into the mitochondria, which is the only place ATP can be produced. NADH+H+ cannot cross the mitochondrial membrane, so it needs to be taken up by dihydroxyacetone phosphate
41
Source of Vit.K/Phylloquinone
Green plants, kale, avocado
42
Role of Vit.K/Phylloquinone
Gamma carboxylation of glutamate activates blood clotting factors. Vit.K also activates osteoralsin which is a bone protein, so this helps in bone formation
43
How does blood clotting occur?
Prethrombin gets converted to Prothrombin which activates the blood clotting factors. Gamma-carboxyglutamate plays a role in the conversion of prethrombin to prothrombin.
44
Deficiency in Vit.K/ Phylloquinone
Often in young chicken,
Decreased bone formation, bleeding syndrome in newborns. The reason for this bleeding syndrome is the low synthesis of Vit.K from mother to featus is not good enough.
So low prothrombin level in blood is the cause.
45
An anitvitamin for Vit.K/Phylloquinone
Warfarin, which blocks epoxyreductase in the formation of Vit.K (rat poison)
46
The TCA is located in....?
Mitochondrial matrix, in all cells except RBC
47
Energy balance of TCA cycle:
12 ATP per cycle= 24 ATP
48
Regulators of TCA cycle:
```
Citrate synthase (in=NADH+H+, ATP) (stim=ADP, AcCoA),
Isocitrate DH (in=NADH+H+, ATP) (stim=NAD+, ADP),
Succinate DH (in=oxaloacetate) (stim= succinate)
```
49
Enzyme used during Pyruvate --> AcCoA:
Pyruvate DH
50
Enzyme used during AcCoA --> Citrate
Citrate synthase (regulating enzyme)
51
Enzyme needed for Citrate --> Isocitrate
Aconitase
52
Enzyme needed for Isocitrate --> alpha-ketoglutarate
icocitrate DH (regulating enzyme)
53
Enzyme needed for alpha-ketoglutarate --> Succinyl-CoA
alpha-ketoglutarate DH
54
Enzyme needed for Succinyl-CoA --> Succinate
Succinyl-CoA synthetase
55
Enzyme needed for Succinate --> Fumarate
Succinate DH (regulating enzyme)
56
Enzyme needed for Fumarate --> Malate
Fumarase
57
Enzyme needed for Malate --> OAC
Malate DH
58
Enzyme needed for OAC --> AcCoA
Oxaloacetate DH
59
Name the two main types of Vit.D/Calciferol
Ergocalciferol/Viit. D2 and Cholecalciferol/Vit.D3
60
Dietary vitamin of calciferol is..?
Ergocalciferol is present in sun-cured hay
61
active form of Vit.D/Calciferol
Hydroxylation of vit.D3 make 25-hydroxy-cholecalciferol. The enzyme is 25-hydroxylase.
25-hydroxy-cholecalciferol is further hydroxylated to 1,25-dihydroxycholecalciferol by the enzyme 1-alpha-hydroxylase
62
Regulators in GNG
Hormonal regulaton: Insulin (inhibits) and Glucagon (stimulates).
Allosteric regulation: Citrate, AcCoA (stimulates), ADP, Fructose-2.6-BP (inhibits)
63
Where is the two enzymes in synthesis of 25-hydroxycholecalciferol and 1.25-hydroxycholecalciferol located?
25-hydroxylase enzyme in liver microsomes, and alpha-1-hydroxylase enzyme in kidney mitochondria
64
What is the chemiosmotic theory?
The theory of proton pumping which results in ATP
65
Inhibitor of Complex I in respiratory chain:
Rotenone, which blocks electron flow from Fe-S to UQ
66
Inhibitor of Complex II in respiratory chain:
Malonate
67
Inhibitor of Complex III in respiratory chain:
Antimycin-a, which blocks electron flow from Cytochrome bL to UQ
68
Inhibitor of Complex IV in respiratory chain:
Cyanide and carbon monoxide, which blocks acess of O2 to Cytochrome A3
69
Inhibitor of Complex V in respiratory chain
Oligomycin, which damages FO subunit
70
Role of VIt.D/Cholecalciferol in young animals:
In young animals it is increasing the mineralization of newly formed bones.
71
Role of Vit.D/Cholecalciferol in older animals:
In older animals Vit.D will demineralizate the pre-existing bones because of parathormone (PTH) like activity of Vit.D.
72
Role of Vit.D/Cholecalciferol in any ages:
At any ages, Vit.D will have a Ca2+ and Pin absorption that increases in the intestinal epithelial cells
73
Deficiency of Vit.D/Cholecalciferol in young animals:
Decreased mineralization of newly formed bones -> rickets (bowed legs)
74
Deficiency of Vit.D/Cholecalciferol in older animals:
Demineralization of pre-existing bones because of parathormone secretion (concequence of low Ca2+ in blood) -> Osteomalacia (softening of bones)
75
Deficiency of Vit.D/Cholecalciferol at all ages:
Blood test -> Ca2+ and Pin is deacreased, and also alkaline phosphate activity is increased because of stimulated osteoblast function in order to repair damaged bones.
Alkaline phosphate test is to measure the amount of ALP in the blood. It is used to diagnose liver damage and bone diseases.
76
Symptoms of Hypervitaminosis of Vit.D:
Ca2+ and Pin increases in the blood, that leads to atherosclerosis, calcification of organs, tissues and membranes: gastrointestinal problems. Also, Ca2+ and Pin reabsorption increases in the kidney tubular epithelial cells that leads to Ca2+ and Pin precipitation in the lumen: Kidney failure!
Also: slow growth,
77
Role of PPP
Primarily an anabolic pathway that utilizes the 6-carbon sugars (glucose) to create 5-carbon sugars and reducing equivalents (NADPH). PPP will completely oxidize glucose to CO2 and H2O
78
What is the NADH+H+ created from PPP used in?
In synthesis of FA and steroid/cholesterol synthesis.
79
Primary function of PPP
Provide cell with ribose-5-P for synthesis of nucleotides and nucleic acids, AND metabolize dietary pentose sugars derived from digestion of nucleic acids, and rearrange carbon skeletons of dietary carbohydrates into glycolytiv/gluconeogenic intermediates.
80
Location of PPP
cytosol in liver, adipose tissue, adrenal cortex, testis and lactating mammary glands. These locations have high levels of PPP enzymes.
81
Regulation of PPP
1. NADPH + H+ increases, Pentose increases = Whole PPP doesn't work. It gets inhibited.
2. NADPH + H+ increases, Pentose decreases = No oxidative PPP.
3. NADPH + H+ decreases, Pentose increases = whole PPP will work (normal direction).
4. NADPH + H+ decreases, Pentose decreases = oxidative part will work, non-oxidative part doesn't work.
82
What does the oxidative part of the PPP?
Producing NADPH and is irreversible
83
What does the non-oxidative part of PPP?
Produces RIbose-5-phosphate and it inconvert sugars. It is reversible.
84
The conversion of B-carotene til Vit.A in cattle happens in...?
liver and mammary gland
85
The conversion of B-carotene to Vit.A happens in...?
the wall of the small intestine in most mammalian spp.
86
Which enzyme takes place in the breakdown of B-carotene?
B-carotene 15,15'-dioxygenase (carotenase)
87
How many Retinol is formed from 1 B-carotene?
2 Retinol/Vit.A molecules
88
Retinol is converted to Retinal by the enzyme....?
Retinol DH
89
Name som derivates of Retinol/Vit.A:
Retinal, 3-dehydroretinol, Retinoic acid and Retinyl-ester
90
Where is Retinol stored?
in the liver as Retinyl-esters
91
How is the blood glucose level regulated?
by glycogenolysis, glycogenesis, glycolysis and GNG
92
Blood glucose level in non-ruminants:
4-5 mmol/L
93
Blood glucose level in ruminants:
2-3 mmol/L
94
Blood glucose level in birds:
8-9 mmol/L
95
What so special with the blood glucose level in birds?
Newborn ungulates in the 1-3 first days - the fructose gives the blood sugar.
96
What happens in the pancreas when the body has too low blood glucose level?
The pancreas releases glucagon from the alpha-cells.
97
What happens in the pancreas when the body has too high blood glucose level?
The pancreas releases insulin from the beta-cells.
98
What does the liver do when the blood glucose level is too low?
The liver release glucose INTO the blood.
99
What does the fat cells do when the blood glucose level are too high?
The fat cells take in glucose FROM the blood
100
GLUT-1 transporter gives glucose to...?
erythrocytes and brain
101
GLUT-2 transporter gives glucose to...?
liver, kidney and intestines
102
GLUT-3 transporter gives glucose to...?
brain
103
GLUT-4 transporter gives glucose to...?
muscle and adipose tissue
104
What is so special about the GLUT-4 transporter?
GLUT-4 is insulin sensitive. This means that insulin is binding to this transporter and an insulin receptor makes a signal transduction cascade which allows GLUT-5 to transport glucose into the cell.
105
What effect does adrenalin have on blood glucose conentration?
It will cause hyperglycemia
106
Where is adrenalin produced?
Adrenal medulla
107
Which affected pathways and how will adrenalin affect?
```
Muscle glycogenolysis (positive)
Muscle glycogenesis (negative)
```
108
What effect does glucagon have on the blood glucose concentration?
It will cause hyperglycemia
109
Where is glucagon produced?
In pancreas alpha-cells
110
Which affected pathways and how will glucagon affect?
Liver glycogenolysis, GNG (positive)
| Liver glycogenesis, glycolysis (negative)
111
What effect does glucocorticoids have on the blood glucose concentration?
It will cause hyperglycemia
112
Where is glucocorticoids produced?
In adrenal cortex
113
Which affected pathways and how will glucocorticoids affect?
GNG (positive)
| Glycolysis (negative)
114
What effect does ACTH have on the blood glucose concentration?
It will cause hyperglycemia
115
Where is ACTH produced?
in adenohypophysis
116
Which affected pathways and how will ACTH affect?
Glucocorticoids (positive)
117
What effect does STH (growth hormone) have on the blood glucose concentration?
It will cause hyperglycemia
118
Where is STH (growth hormone) produced?
in adenohypophysis
119
Which affected pathways and how will STH (growth hormone) affect?
Lipolysis (positive)
| GNG from amino acids (negative)
120
What effect does insulin have on the blood glucose concentration?
It will cause hypoglycemia
121
Where is insulin produced?
in pancreas beta-cells
122
Which affected pathways and how will insulin affect?
Glucose uptake, glycogenesis, glycolysis (positive)
| Glycogenolysis, GNG, fat and liver degradation (negative)
123
Name some of Pyridoxine/Vit.B9
Pyridoxamine, Pyridoxal, Pyridoxal phosphate, Pyridoxamine phosphate.
124
Role of Vit.B9/Pyridoxine
Maintaining brain function, make RBC, breakdown of proteins and antibody synthesis
125
Source of Vit.B9/Pyridoxine:
beans, nuts. egg, meat, fish, grains, cereals, green vegetables.
126
Which is the common available synthetic form of the vit.B9?
Pyridoxine hydrochloride, which is easily crystallizable and odorless. This is the form of pyridoxine typically used in nutrient supplements and animal diets.
127
With help of which enzyme does pyridoxine gets converted to pyridoxal?
NADP+-dependent pyridoxine DH
128
What happens with Pyridoxine/Vit.B9 in presence of ATP?
pyridoxal kinase phosphorylates pyridoxal into the active coenzyme "pyridoxal phosphate" (PALP)
129
Which is the final elimination product of Vit.B9?
the biologically inactive pyridoxic acid, which is excreted in the urine.
130
Can Vit.B9/Pyridoxine get stored in the body?
Yes, in small amounts only. Because the microflora in rumen and colon is able to synthesize the vitamin B9.
131
Location of fructolysis
Cytoplasm in liver
132
Enzyme of convertion from Fructose-1-P to both Dihydroxyacetone-P AND Glyceraldehyde in Fructolysis
Fructose-1-P aldolase
133
Location of fructogenesis?
Placenta in ungulates, other spp: cytoplasm in seminal vesicle.
134
Steps of fructogenesis:
Glucose to Sorbitol to Fructose. The enzymes are = aldolase reductase, and sorbitol DH
135
Location of Galactolysis:
In liver
136
Location of Galactogenesis
Mammary gland (lactose synthesis), bone and cartilage
137
Components of milk
Dry matter is 13 % of the whole. It consists of milk protein, milk fat and milk sugar. Then we have the water phase which is 87 % of the whole.
138
Milk protein consists of...?
Casein, lactalbumins (alpha and beta), beta-lactoglobulin
139
Where does the milk fat come from?
synthesized from mammary gland or derived from blood
140
Components of milk fat:
Triacylglyerols (plasma), FFA (plasma), cholesterol, phospholipids, fat soluble vitamins, essential fatty acids.
141
What is milk sugar?
Lactose (disaccharide) = Beta-D-glucose + Beta-D-Galactose, in Beta-1,4 bond
142
Where is milk sugar made?
Only made in mammary gland and made through lactose synthesis.
143
What is lactose intolerance?
Not enough lactase due to genetics or virus. Will cause diarrhea.
144
How to effect the percent of milk fat?
Diet=less roughage (less fiber), more forage.
Leads to the chewing= less saliva (pH=8,5.
Leads to rumen in pH gets low.
Leads to that proprionate-producing microbes grow intensively, but acetic acid-producing microbes grow slowely.
Leads to AcCoA decreases.
Leads to FA synthesis decreases.
145
Where is Vit.E/Tocoferol stored?
In the liver and adipose tissue
146
Source of Vit.E/Tocoferol:
Plant oils, wheat, corn, avocado, fish and alfalfa
147
What can destroy the activity of the vitamin E/Tocoferol?
UV light and oxidation
148
How is Vit.E excreted?
it is oxidized, then bound to glucoronic acid
149
Deficiency of vit.E/Tocoferol?
Products of auto-oxidation (lipd peroxides) are detected in the adipose tissue. These toxic products cause ultra-structural &biochemical changes in a number of cellular membranes.
150
Where is the predominant route of absorption of Vit.E?
Lymph
151
Main excretory route of Vit.E metabolites?
The bile
152
Biochemical role of Vit.B2/Riboflavin:
H-uptake and transport, Aerob dehydrogenase (H2O2 production), Anaerob dehydrogenase (respiratory chain), AND Redix enzymes
153
Deficiency of Vit.B2/Riboflavin:
Rat: dermatitis, growth failure, keratitis of cornea.
Poultry: leg paralysis (curled toe paralysis), feather loss.
Horse: Periodic opthalmia ("moon blindness") and secondary infection of cornea.
Mammals: Fatty liver (beacuse of accumulating fatty acids as triacylglycerols), dermatitis, hair loss.
All species: Glossitis, angular stomatitis, pale lips, ulcerated corners of mouth
154
Where does oxidative deamination take place?
In all tissues, especially the liver, under aerob condtitions.
155
How does an amino acid become a keto acid?
Amine functional group is removed as ammonia (ammonia enters Urea cycle) and is replaced by a ketone group.
156
Which amino acid does the oxidative deamination often occur to?
Glutamate, because it's the endproduct of many transamination reactions.
157
How is the oxidative deamination regulated?
By allosteric regulation og de enzyme glutamate dehydrogenase by ATP (inhibiton) and ADp (stimulating)
158
Which compound is made from oxidative deamination of Glutamate?
alpha-ketoglutarate
159
Name some ketogenic amino acids
Leucine
160
Name some glucogenic amino acids
Alanine and glycine
161
Which is the most usual keto acid involved in the transaminations?
alpha-ketoglutarate
162
What is the enzymes called during transamination?
Transaminases. All amino acids have transaminase, except Thr, Lys and Pro
163
Which hormones can stimulate GNG in the liver which also function as an antagonist to insulin (not Glucagon)
Cortisol and Cortison (from adrenal cortex)
164
Steps of metabolism of Vit.B3/Nicotinamide
Feeds containing pyridine nucleotide-derivates are broken down in digestive tract to make nicotinic acid, which is absorbed in the circulation system, transported via portal vein to liver. There, nicotinic acid or nicotinamide is converted to NAD+ (nicotinamide adenin dinucleotide). NAD+ can be later phosphorylated into NADP+ (nicotinamide adenine dinucleotide phosphate)
165
Which other synthesis can we make Nicotinic acid? (not from pyridine nucleotide)
Nicotinic acid can be synthesized in the liver from the essential amino acid Tryptophan. Only done when very high amount of Tryptophan.
166
How is Vit.B3/Nicotinamide excreted?
In the urine unchanged by ruminants, but is methylated before excretion in monogastric animals
167
What are essential amino acids?
Amino acids that can not be synthesized in the body so they have to be included in the diet.
168
Name som essential amino acids:
MATT VILPHLY = Methionine, Isoleucine, Leucine, Phenylalanine, Histidine, Lysine
169
Which compound serves usually as the amine group source in the transamination for non-essential amino acids?
Glutamate
170
How do we get a biogenic amine? how is the synthesis?
Decarboxylation of an amino acid with help of coenzyme PALP (Vit.B3). We can also achieve a biogenic amine from transamination of ketones.
171
Location of carboxylation of amino acids:
brain, intestinal epithelial cells, intestines
172
Role of biogenic amines:
precursor of hormones, alkaloids, nucleic acids, proteins and amines. They are also a source of nitrogen.
173
It is safe to eat biogenic amines?
Yes, in fermented food, but NOT in non-fermented food.
174
Biogenic amines is synthesized of what?
microbes in the gut, and animal metabolites
175
Decarboxylation of Histidine. What happens? Which role does the biogenic amine has?
We get Histamine. With help from enzyme HIstidine decarboxylase. Role in inflammation, allergic reaction, neurotransmitter.
176
Decarboxylation of Tyrosine. What happens? Which role does the biogenic amine has?
We get Tyramine. With help from Tyrosine decarboxylase. Role in vasocontrictor, neurotransmitter, muscle contriction, in headache.
177
Decarboxylation of 5-OH-Tryptophan. What happens? Which role does the biogenic amine has?
We get Serotonine. With help from 5-OH-Tryptophan decarboxylase. Role in neurotransmitter, regulation of sleep/wake.
178
Decarboxylation of Serine. What happens? Which role does the biogenic amine has?
We get Cholamine. With help from Serine decarboxylase. Role in constituent of phospholipids.
179
Decarboxylation of Cysteic acid. What happens? Which role does the biogenic amine has?
We get Taurine. Role in conjugating bile acids to bile salts
180
Decarboxylation of Gamma-Glutamate + Cysteine + Glycine. What happens? Which role does the biogenic amine has?
We get Gluthathione. Role in antioxidant (eliminate ROS, free radicals). PPP supplies RBC with NADPH+H+ to maintain the reduced form of Gluthathione.
181
What can be the cause if we have inability to maintain reduced form of Gluthathione in RBC?
It leads to increased collection of peroxides which weakens the cell wall and Hemolysis (rupture) occurs.
182
Gamma-Glutamyl cycle: Amino acids goes through cell membrane and gets converted to....? with help of enzyme....?
Glutathione. Enzyme is Gamma-glutamyl transpeptidase
183
Gamma-Glutamyl cycle: Glutathione gets converted to.....? With help of enzyme....?
Gamma-Glutamyl-Amino acid. Enzyme is Gamma-glutamyl transpeptidase
184
Gamma-Glutamyl cycle: Gamma-Glutamyl-Amino acids gets converted to.....? With help of enzyme....?
5-oxo-Proline. Enzyme is Gamma-glutamyl cyclotransferase
185
Gamma-Glutamyl cycle: 5-oxo-Proline gets converted to.....? With help of enzyme....?
Glutamate. Enzyme is 5-oxoprolinase
186
Gamma-Glutamyl cycle: Glutamate gets converted to.....? With help of enzyme....?
Gamma-glutamyl-Cysteine. Enzyme is Gamma-Glutamylcystein synthetase
187
Gamma-Glutamyl cycle: Gamma-Glutamyl-Cysteine gets converted to.....? With help of enzyme....?
Glutathione. Enzyme is Glutathione synthetase
188
Explain the degradation of biogenic amines:
Biogenic amines gets converted to Imine with help of MAO enzyme (monoamine oxidase). Then Imine gets converted to Ammonia (NH3) and Aldehyde. The Ammonia and aldehyde gets oxidized to Acid. Acid enters Beta-oxidation.
189
Metabolism of vit.K1/Phylloquinone
indirect product of photosynthesis in plant leaves. E.g: cabbage, alfalfa.
190
Metabolism of Vit.K2/ Menaquinone
product of microbial synthesis. E.g: dairy products. Nor storage in liver
191
Metabolism of Vit.K3/Menadione
synthetic origin. No side chains. Produced in the liver.
192
Derivates of Vit. K/Phylloquinone
Phylloquinone (K1), Menaquinone (K2) and Menadione (K3). They are all substituted naphtoquinones and transported by chylomicrons to liver.
193
Excretion of Vit.K:
with urine and bile, bound to Glucuronate
194
Special about metabolism of Vit.K
Naphtoquinone ring cannot be synthesized in body so it has to be added through diet. Plant or animal origin. Comes with bile to intestine. Needs bile for absorption to liver.
195
Source of Ascorbic acid/Vit.C:
fresh fruit, leafy vegetables, citrous fruit.
196
What kind of absorption of Vit.C is in the instestines?
Aktive transport/energy-requiring (human, primates, guinea pig) and passiv transport/simple diffusion (all others)
197
Where is Vit.C/Ascorbic acid found in the body?
Glandular tissue (pituitary gland, andrenal gland, corpus luteum)
198
Why can't human, monkey and guinea pig synthesize Ascorbic acid/Vit.C?
apparently due to the absence of Gulonolactone oxidase, which is found in the liver of those species that synthesize the vitamin.
199
Precursor of Vit.C/Ascorbic acid
D-Glucoronic acid (formed from Glucose)
200
Where does the synthesis of Vit.C/Ascorbic acid take place?
In the liver, but birds can also synthesize it in the kidney.
201
Excretion of Vit.C/Ascorbic acid:
Happens in the oxidized form /Dehydroascorbic acid or Oxalic acid)
202
Name the whole synthesis of Ascorbic acid/Vit.C
Glucose - UDP-Glucose - UDP-glucoronic acid - D-glucoronic acid - L-Gulonate - L-gulonolactone - 2-keto-L-gulonolactone - L-ascorbic acid
203
Most important enzyme in the synthesis of Vit.C/Ascorbic acid?
L-gulonolactone oxidase. Lacks in human, monkey and guinea pig.
204
Name the enzymes that catalyzes the synthesis of Ascorbic acid/Vit.C:
UDP-glucose - Glucoronidase - Glucoronate reductase - Aldonolactonase - L-gulonolactone oxidase. Final step is an isomerisation to Ascorbic acid.
205
Why is ammonia toxic?
It can cross the blood brain barrier, it can remove alpha-ketoglutarate from the TCA cycle som no energy gets produced, and it can cause nervous system symptoms.
206
How can we detoxificate ammonia?
By urea cycle (most important, tho its missing in birds), Glutamine synthesis/transport, purine syntheis (birds)
207
How can ammonia enter the body?
By L-Glutamate synthesis with L-glutamate dehydrogenase enzyme in the oxidative deamination. Ammonia can also enter through the biogenic amine degradation and through the GI tract via absorption e.g ruminants. Final way is the protosystemic shunt: NH3 goes from intestine to circulation, bypassing the liver which can lead to possible toxicosis. It happens when blood from portal vein enters vena cava and not the liver. If ammonia reaches the brain, it will cause an inhibiton og TCA cycle.
208
Where is the location of the urea cycle?
in the mitochondria and cytoplasm of the liver
209
Alternative detoxification pathways of ammonia:
1) Glutamine synthesis, where Glutamate + NH3 becomes Glutamine with help of Glutamine synthase enzyme.
2) Asparagine synthesis, where Aspartate + NH3 becomes Asparagine with help of Asparagine synthase enzyme.
3) L-glutamate synthesis, where alpha-ketoglutarate + NH3 becomes L-Glutamate with help of L-glutamate DH.
4) Purine synthesis (in birds), where the start molecule is PRPP (phosohooribosyl pyrophosphate). It binds to 4 N of purine base. So: CMP becomes Glutmate, and AMP becomes Aspartate
210
Name the molecules in the urea cycle, step by step:
NH3 + H2CO3 becomes carbamoyl phosphate with the enzyme "carbamoyl-P-synthetase". Then carbamoyl-P and Ornithine (from final product of Urea cycle, so; last step of the previous cycle) gets converted together to Citrullin with help of "Ornithine carbamoyl transferase". This happens in the mitochondria. Then Citrullin --> Argininosuccinate with enzyme "Argininosuccinate synthetase" since Aspartate enters the cycle. This is now happening in the cytoplasm. Argininosuccinate --> Arginine with enzyme "Argininosuccinase lyase". At the same time, Fumarate leaves the cycle and becomes Malate-->OAC-->Aspartate (TCA cycle) This Aspartate will enter the cycle again at the step of Citrullin becomes Argininosuccinate. Arginine-->Ornithine. Urea leaves at this step and is excreted in the urine.
211
How can the body get essential fatty acids?
Only via diet! From plants!
212
Name some unsaturated, essential fatty acids:
1) Linoleic acid
2) Linolenic acid
3) Arachidonic acid
213
Tell something about Linoleic acid!
It is an unsaturated, essential fatty acid. Produced in plants and found in animals. Produced from Oleic acid. It is a 18-carbon chain, 2 double bonds (9,12) and Omega 6
214
Tell something about Linolenic acid!
It is an unsaturated, essential fatty acid. Only found in animal membranes, synthesized in plants. Produced from Oleic acid. It is a 18-carbon chain, 3 double bonds (9,12,15) and Omega 3
215
Tell something about Arachidonic acid!
It is an unsaturated, essential fatty acid. It becomes essential if there is lack of linoleic acid, or inability to convert linoleic acid to Arachidonic acid. It is a 20-carbon chain, 4 double bonds (5,8,11,14) and omega 6
216
Tell about the synthesis of Omega-6-fats!
Linoleic acid - Gamma-linoleic acid - Arachidonic acid - Proinflammatory prostaglandins and leukotrienes.
217
What is the role of omega-6-fats?
Promotes blood clotting. Leads to high blood pressure.. Mood swings.
218
Tell about the synthesis of Omega-3-fats!
Linolenic acid - Eicospentainoic acid (EPA) - Docosahexaenoic (DHA) - Anti-inflammatory prostaglandins and leukotrienes
219
What is the role of Omega-3-fats?
Promotes blood thinning, which leads to lower blood pressure. Mood stabilization.
220
Sources of essential fatty acids:
Linoleic & linolenic acid is found in vegetable oil. Arachidonic acid is found in animal fat.
221
Tell 2 interesting facts about Essential fatty acids!
1) Mammals cannot produce double bonds beyond C9 & C10.
| 2) Omega 1-9 cannot be synthesized by birds & mammals
222
What is the result of deficiency in essential fatty acids?
It's rare, but it may be observed in young animals with low -fat diet. It will cause membrane damage, skin problems, hair loss, fertilization problems, inflammation problems (chronic) and blood clotting issues. Symptoms of deficiency can be prevented by an essential fatty aid intake of 1-2 % of the total energy.
223
Biochemical role of essential fatty acid
1) Membrane formation
2) EFA found in structural lipids (phospholipids) of cell membrane.
3) Prostaglandins synthesis - Formed in all tissues, dietary precursor of prostaglandins --> Linoleic acid converted to Arachidonic acid with help of "desaturase"-enzyme
224
Can animals synthesize essential fatty acids?
No. Plants can synthesize linoleic acid and linolenic acid from Oleic acid, but animals are unable to do that. On the other hand, animals can synthesize Arachidonic acid from Linoleic acid.
225
How do we create prostaglandins in the body (from essential fatty acids)?
The dietary precursor of prostaglandins is Linoleic acid. It is converted to the immediate precursor of the prostaglandins; Arachidonic acid. The next step is the oxidation and cyclization of arachidonic acid to create prostaglandins.
226
Where is the location of the purine nucleotide synthesis?
In cytosol in each cell type
227
Name the purine bases!
Adenine & Guanine
228
Describe the synthesis of purine nucleotides!
Glucose - Glucose-6-P - Ribose-5-P (trough PPP-pathway) - 5-phosphoribosyl-1-pyrophosphate (PRPP) - 5-phosphoribosyl-amine - Inosine monophosphate (IMP)
229
Allosteric regulation of purine nucleotide synthesis:
Inhibition or stimulation of the enzyme "PRPP amidotransferase".
Stimulation: PRPP
Inhibition: IMP, AMP, GMP
230
What is the location of degradation of purine nucleotides?
In cytosol in each cell type, only until Uric acid - then the liver.
231
What is the clinical relavence of dedradation of purine nucleotides?
Uric acid is bad soluble in water, therefore it will precipitate in joints, serosal membranes and kidney. This will lead to inflammation, gout/uricosis.
232
What can be the treatment after precipitation of Uric acid in the joints, serosal mebrane and kidney that can lead to inflammation and uricosis?
Allopurinol, which is an inhibitor of xanthine oxidase, since it has similar structure as hypoxanthine.
233
What is the coenzyme used in degradation of purine nucleotides?
FAD- makes FADH2
234
Which animals can excrete uric acid in urine?
Primates, birds and reptiles, and dalmation, because they don't have the enzyme "Uricase" which catalyzes Uric acid to Allantoine.
235
Which animals can excrete allantoine in urine?
Dogs, cats, horses, ruminants and pigs. NOT dalmation, because fast transport-gene of Uric acid in liver is mutated.
236
Biochemical role of NIcotinamide/ Vit.B3
H+ uptake and transport:
Becomes NAD+ - acts as a cofactor in e.g. Lactate-DH, Pyruvate-DH, Malate-DH, Isocitrate-DH.
Becomes NADP+ and produces NADPH+H+ - acts as a cofactor in e.g. Glucose-6-P DH, 6-P-Gluconate DH. NADPH+H+ is needed in 1st and 2nd reductase of FA synthesis, Gluthatione reductase, Epoxy reductase.
237
NAD+ is used in...?
Glycolysis, Gluconeogenesis, TCA cycle, FA degradation, Ketogenesis
238
NADP+ is used in...?
PPP, FA synthesis, cholesterol synthesis
239
Deficiency in Nicotinamide/ Vit.B3:
Pellagra:
Human: diarrhea, dermatitis, dementia (DDD)
Dog: Black-tongue
Birds: poor growth, slipped tendons, leg disorders.
240
Where is the location of synthesis of pyrimidine nucleotides
Cytosol in each cell type
241
Allosteric regulation of synthesis of pyrimidine nucleotides:
1) Carbamoyl phosphate synthetase II (eukarytoes) with PRPP as stimulator and UTP as inhibitor.
2) Aspartate transcarbamoylase (prokaryotes).
3) CTP-synthetase with GTP as stimulator and CTP as inhibitor.
242
Energy balance of synthesis of pyrimidine nucleotides is....?
-7 ATP
243
Where is the location for degradation of pyrimidine nucleotides?
In cytosol in each cell type
244
Regulation of the degradation of pyrimidine nucleotides:
It depends on the substrate concentration, amount of nucleotides to degredated.
245
Name the pyrimidine bases:
Cytosine, Uracil and Tymidine
246
What are the sources of biotin/Vit.H?
Plant origin: nuts, soybean, grains, vegetables.
Animal origin: milk, liver, egg yolk (egg white contains avidin, which is an antivitamin that makes the biotin non-absorbable).
Yeast
247
Does biotin/ Vit.H has microbial synthesis?
Yes
248
Storage or no storage of Biotin/ Vit.H in the body?
No storage
249
Are biotin/ Vit.H absorbed by active or passiv transport?
Passive
250
Where does the synthesis of biotin/ Vit.H enzyme happen?
In the liver
251
In which form is biotin/ Vit.H excreted by urine
excreted as Biotin sulpoxide
252
Biochemical role of Vit.H/ Biotin
1) Role in Pyruvate carboxylation (in GNG). Pyruvate and CO2 gets converted to Oxaloacetate with help from Pyruvate carboxylase and Biotin.
2) Role in AcCoA carboxylation (in FA synthesis). AcCoA, Biocarbonate and ATP gets converted to Malonyl-CoA and ADP+p with help from AcCoA carboxylase and Biotin.
3) Role in Proprionyl-CoA carboxylation (very important in Ru!). ProprionylCoA, ATP and HCO3 gets converted to D-methylmalonyl-CoA + ADP+p with help from ProprionylCoA carboxylase and Biotin.
4) Activates protein/Aa metabolism in hair and hoof!
253
What can be caused by deficiency of Biotin/Vit.H?
1. Raw egg white (contains Avidin that makes biotin non-absorbable.
2. Rats: "spectacle eyes". dermatitis, slow growth and weight loss.
3. Poultry: Low microbial synthesis, dermatitis, poor feathering, reduced egg production.
4. Pigs: loss of hair, scaliness, bloody ulcer on feet and tongue epith.
5. Horses: damaged hooves
6. All spp: Hair loss
254
Biochemical role of Haemoglobin:
Binds the oxygen in the RBC. It is carried around the body to allow aerob respiration to provide energy. Haemoglobin can also bind to competitive inhibitors like CO, and allosteric ligands such as CO2 and NO
255
Location of Haemoglobin synthesis is....?
in mitochondria and cytoplasma.
256
Location for Haemoglobin degradation is...?
spleen, liver, bone marrow - MPS cells.
257
Regulatory enzyme of Haemoglobin is...?
Aminolevulinic acid synthase
258
Source of Vit.B1/Thiamine:
Ruminants which has bacteria that can provide this vitamin. Other animals must get thiamine from the diet. e.g. ceral grains.
259
Metabolism of Thiamine/ VIt.B1:
The vitamin is absorbed in the small intestines (duodenum/jejunum) and transported to the liver. In the liver, it is phosphorylated with help of ATP to Thiamine pyrophosphate (TPP) which is a coenzyme. The enzyme catalyzing this process is "thiamine kinase". The coenzyme TPP helps in the reaction of pyruvate DH and alpha-ketoglutarate DH
260
Tell about the storage of Thiamine/ Vit.B1!
The vitamin is stored in very small amounts in the body, EXCEPT in swine! Pork muscle is relatively rich in thiamine.
261
Average lifespan of porphyrines is...?
60-160 days
262
What happens with the old cells in the body?
the old cells are removed from circulation and degradated in the spleen ( a little bit in bone marrow and other tisses).
263
What happens when we break down the hemoglobin?
leads to a separation of Heme and globin. The globin is hydrolysed to Aa which is used in protein synthesis
264
What happens during the first step of Heme after splitting Heme and Globin?
A split of methylene bridge to form Biliverdin. This is catalyzed by heme oxygenase (need O2 and NADPH). Fe3+ gets released and reduced to form new Hb molecules
265
After the split of methylene bridge of Heme, to form Biliverdin, what happens next?
The central methiene bridge if biliverdin is reduced by biliverdin reductase to form Bilirubin. (need NAPH)
biliverdign & bilirubin = bile pigments.
266
After forming Bilirubin by biliverdin reductase, what is the next step?
Bilirubin (indirect) is transported to liver by binding to albumin.
267
What happens with the Indirect bilirubin after entering the liver by attaching to albumin?
It dissociates from albumin and enters hepatocytes
268
What happens after the indirect bilirubin dissociates with albumin in the liver and enters the hepatocytes?
It gets conjugated to glucoronic acid and is now called direct bilirubin. it is soluble in water and is the usual form of bilirubin in bile.
269
What happens after indirect bilirubin gets conjugated by glucoronic acid and become direct bilirubin?
Direct bilirubin is secreted into bile, and then intestines.
270
What happens after direct bilirubin is secreted into bile and then intestines?
It is hydrolyzed into urobilinogen/stereobilinogen by bacterial enzymes.
271
What happens after direct bilirubin is hydrolyzed into Urobilinogen and sterobilinogen by bacterial enzymes?
Some of the urobilinogen/stereobilinogen is oxidized to urobilin/stereobilin, and this gives urine and feces its color. UBG can also be absorbed by the portal system, and oxidized to direct bilirubin again and excreted in bile (enterohepatic circulation). Small amount of UBG can escape removal from blood by the liver. This is excreted by the kidney instead.
272
Tell me about Myoglobin!
1 heme + 1 polypeptide chain. It is the O2 binding molecule in skeletal muscles. For diving animals, such as seals and whales. Whe? They are able to be under water for a long time because they have a large amount of myoglobin in the muscle.
Location: red skeletal muscle and heart.
Myoglobin binds O2 more firmly than Hb.
273
What is a porphyrin?
Porphyrins are derivate of porphin. Porphin is cyclic compund formed by the linkage of 4 pyrrole rings with methenyl bridges
274
Tell me about cytochromes!
they are hemoproteins. Ulike the heme groups of hemoglobin, the cytochrome iron atom is reversibly converted from its Fe3+ to its Fe2+ form. It is a reversible carrier of electrons in the respiratory chain. We have 3 major groups of cytochromes: a & a3, b, and c
275
Tell me about Catalase!
Contains Fe3+ protoporphyrin IX. Has the ability to react with H2O2. Consists of 4 subunits (heme-groups). Peroxisomes in liver contains a lot of catalse.
H2O2 --> H20 + 1/2 O2, with help of catalase.
It has the same function as peroxidase
276
Tell me about peroxidase!
Contains Fe3+ protoporphyrin IX. Ability to react with H2O2. And it catalyzes the overall peroxidatic reaction:
SH2 + H2O2 ---> S + 2H20, with help of peroxidase.
It has the same function as catalase
277
Tell me about Iron uptake!
Dietary iron is in the Fe3+ form. The iron must first enter the acidic environment in the stomach. The acidity will release the iron from proteins. The iron will then pass into the alkaline environment of the small intestine. Ascorbic acid/Vit.C will reduce Fe3+ to Fe2+ which will then be available for absorption.
278
Tell me about Iron absorption!
The amount of apoferritin and its degree of saturation in the mucosal cells, control the iron absorption. Apoferritin is a water-soluble protein which can bind to Fe3+ irons. The complex of apoferritin and iron is called ferritin. When all the apoferritin in the mucosal cells is saturated with iron to form ferritin, no further absoption can occur (mucosal block)
279
Tell me about Iron transport!
After the absorption of the iron in the mucosal cells, the iron is rapidly bound to Transferrin in the plasma. Transferrin is a protein which has the ability to bind to 2 Fe3+ ions.
280
Tell me about Iron distribution/storage!
In the tissues, iron that is not required for hemoglobin and myoglobin synthesis, is transferred to the reticulo-endothelial cells of liver, spleen and bone marrow for storage. It is stored as these iron-storage compounds called ferritin and hemosiderin.
So: Iron is used in RBC (70-80 % Fe2+ in haemoglobin), Muscle (in myoglobin) and storage (in form of Ferritin and Hemosiderin)
281
Tell me about iron excretion!
Excretion of iron in the normal body is very low. The very small amounts lost in exfoliated skin cells, hair, nails, milk and urine remain constant.
Large unabsorbed amount of iron is excreted through the feces.
282
What is the disease when the body absorbs too much iron?
Hemochromatosis
283
Biochemical role of Vit.B1/Thiamine
1. Cofactor in oxidative decarboxylation of alpha-keto acids (pyruvate and alphaketoglutarate)
2. Coenzyme of transketolase in PPP (Ribose-5-P --> Fructose-6-P with enzyme Transketolase and coenzyme TPP.
284
Name some defeciency in Thiamine/Vit.B1:
Lower production of ATP since Thiamine plays a role in the oxidation of pyruvate and alphaketoglutarate which is in the carb metabolism - yielding energy.
Humans: Beri-Beri disease that affects the muscles, heart and nerves.
Poultry: affects nervous sytem: lameness, retracted head.
Ruminants: can produce thiaminase in the rumen, which destroys the thiamine. This will cause Cerebrocortical neurosis.
285
How is lipids absorbed?
Absorbed from the diets in the intestines -> they are insoluble in water. Goes through emulsification via bile salts. Bile salts are synthesized in liver and excreted in bile. Bile salts are amphipathic (one hydrophilic and one hydrophobic part) and so they surround the fat droplets to form micelles. This provides an increased surface area for the action of the enzyme "pancreatic lipase".
The lipids are absorbed by the villi on the intestinal wall, and after crossing the intestinal membrane, the FA reform to Triglycerides.
286
What are lipids broken down to?
2 FA and 1 monoglyceride.
287
Where is the location of lipolysis?
In the adipose tissue
288
How is lipolysis regulated?
+ : adrenalin and glucagon
| - : insulin
289
What is the role of lipolysis?
To make energy of the stored fat by breaking dow lipids. It involves hydrolysis of triacylglycerides into glycerol and free fatty acids.
290
Where is the location of Lipogenesis?
In the liver and adipose tissue
291
How is Lipogenesis regulated?
Stimulated by a diet high in carbs, and several hormones. Insulin stimulates and Glucagon inhibits.
High concentration of long chain FA also inhibits lipogenesis.
292
What is the role of Lipogenesis?
It's a process where AcCoA is converted to triglycerides (fat). Through lipogenesis, the energy contained in AcCoA can be stored for a long time in form of fats when the total energy that comes with food is not needed immediately for metabolic processes. Lipogenesis is the process of both fatty acid synthesis and triglyceride synthesis.
293
Where are fatty acids produced?
In the cytoplasm of cells by repeaetedly adding two-carbon units to AcCoA.
294
Where are triglycerides produced?
in the endoplasmic reticulum of cells by bonding three fatty acids to each glycerol molecule.
295
What is the coenzyme under Lipogenesis?
Fatty-acyl-CoA
296
What is the biochemical role of vit.A/Retinol that has something to do about the epithelial cells?
Maintenance of normal epithelial cell multiplication and differentiation. Hypovitaminosis will cause xerophthalamia (drying condition of cornea and conjunctiva of eye), abnormal keratinization of GI-tract, airway epith. and skin (loosing appetites because of keratinizationof the taste buds)
297
What is the biochemical role of Vit.A/Retinol that has something to do about glycoproteins?
Role in synthesis of glycoproteins (mucus formation). Hypovitaminosis will cause skin and mucus membrane damages because of decreased mucus formation.
298
What is the biochemical role of Vit.A/Retinol that has something to do about chondroitinsulphate?
Role in chondroitinsulphate synthesis. Hypovitaminosis will cause abnormal bone develpoment.
299
What is the biochemical role of Vit.A/Retinol that has something to do about hormones?
Role in male and female steroid hormone synthesis. Hypovitaminosis will cause disorders of the reproductive system and fertilization problems.
300
What is the biochemical role of Vit.A/Retinol that has something to do with vision?
Role in (night) vision. Retinol is oxidized to Retinal which reacts with a molecule eye called "opsin". This makes Rhodopsin. When a photon of light hits Rhodopsin, the Retinal-part of this complex changes from 11-cis to all-trans-form. This will result in transmission of an impulse up the optic nerve. Hypovitaminosis will cause night blindness.
301
Name the biochemical roles of Vit.A/Retinol!
1) Maintenance of normal epithelial cell multiplication & differentiation.
2) Role in syntheis of glycoproteins (mucus formation)
3) Role in chondroitinsulphate synthesis.
4) Role in male and female steroid hormone synthesis.
5) Role in (night) vision.
302
What is the cause of hypervitaminosis in Vit.A/Retinol?
Beta-carotene will never cause hypervitaminosis, because excess is stored in fat reserves. But it can be an deficiency in ruminant and affects reproduction!
- Decreased bone formation
- Change in metabolism of fat-soluble vitamins.
303
Where is the location for degradation of fatty acids/Beta-oxidation?
- Carnithine-shuttle from cytoplasma to mitochondrial matrix.
- B-oxidation in matrix of liver and muscle
304
What is the carnithine-shuttle?
It is responsible for transferring long-chain fatty acids across the barrier of the inner mitochondrial membrane to gain access to the enzymes of B-oxidation.
305
How is the regulation of B-oxidation/degradation of fatty acids?
- CAT I
| - Citrate
306
Role of B-oxidation/Degradation of fatty acids?
It produces energy from fat/FA
307
Name some saturated fatty acids!
- Palmitic acid (C16)
| - Stearic acid (C18)
308
Name some unsaturated fatty acids!
- Oleic acid (C18)
- Linoleic acid (C18)
- Linolenic acid (C18)
- Arachidonic acid (C20)
309
How is Hormone-sensitive lipase activated?
When several hormones (adrenaline, noradrenaline, glucagon, ACTH) bind to receptors on the cell membrane and activate Adenylate cyclase. This enzyme catalyses the synthesis of 2nd messenger cAMP from ATP. cAMP activates protein kinase which activates in cascade of reactions the Hormone-sensitive lipase. The enzyme is not active in the presence of high plasma insulin, since this hormone reduces the intracellular level of cAMP.
310
What is the role of the Hormone-sensitive lipase?
It hydrolyzes stored triglycerides to free fatty acids.
311
What is the body's major fuel storage depot?
Fatty acids stored in adopise tissue in form of triacylglycerols.
312
Where does the fatty acid synthesis take place?
In the cytoplasma of liver, adipose tissue and mammary gland.
313
How is the fatty acid synthesis regulated?
Regulation of the enzyme "AcCoA-carboxylase". Citrate stimulates, FA-CoA inhibits.
314
Food sources of Riboflavin/Vit.B2 is...?
cereals, nuts, milk,eggs,green leaf, vegetables, meat
315
How is Riboflavin transported within the organism?
It is bound to albumin and transported to liver and other tissues
316
How is Riboflavin/Vit.B2 excreted in the body?
Through urine as FMN and through bile as FAD
317
What is the enzyme called that converts Riboflavin to FMN?
Riboflavin kinase
318
What is the enzyme called that converts FMN to FAD?
FMN pyrophosphorylase
319
Where is the location for synthesis of FMN and FAD?
liver
320
What happens under ketogenesis?
Production of ketone bodies under fasting by the liver from AcCoA. Leads to ketosis. Ketone bodies e.g: acetoacetate, Beta-hydroxybutyrate and acetone.
321
Where is the location of Ketogenesis?
Mitochondria of liver (kidney and mammary gland)
322
Why does ketogenesis occur?
AcCoA produced from the B-oxidation of FA can only be used to produce ATP if there is enough OAC around. When carbohydrate intake is low (fasting, diabetes), the liver will use up the OAC to produce Glucose through GNG. Under these conditions, the liver diverts AcCoA to form ketone bodies
323
Locarion of ketolysis
in mitochondria of extrahepativ tissue
324
Energy balance in Ketolysis
26 ATP (from B-OH-butyrate) or 23 ATP (from Acetoacetate)
325
Importance of ketolysis
Source of energy to the body
326
What happens during ketolysis?
Ketone bodies produced in the liver in mitochondria are converted to AcCoA which can go into TCA cycle and oxidative phosphorylation and produce energy.
327
Why is Cobalamine/ Vit.B12 important for the body?
Vit.B12 is important for metabolism, RBC and maintenance of CNS, including brain and spinal cord
328
Source of Cobalamine/Vit.B12?
egg, milk, poultry and shell-fish. Only food from animal origion contains cobalamine, so microbial synthesis is important for herbivores!
329
What happens with cobalamine/Vit.B12 in the stomach? absorption?
In the stomach, intrinsic factor (IF) and R-Glycoprotein are produced. Cobalamine is bound to the R-protein, and in duodenum it is also bound to intrinsic factor (IF).. Absorption by active transport of ileum.
330
Where is Cobalamine/Vit.B12 stored?
In the liver
331
How is Cobalamine/Vit.B12 transported and excreted?
Transported in blodd and cells. Excreted by urine and bile.
332
What is the name of the metabolically active form of Cobalamine/Vit.B12? What is the role?
Deoxyadenosylcobalamine. Function as a coenzyme of methylmalonyl-CoA mutase (B-oxidation)
333
Location of synthesis of Cholesterol?
liver, gonades, (intestines)
334
What is the importance of cholesterol syntheis?
membrane constituent (strength, fluidity), precursor of bile salts and steroids, and Vit.D
335
Source of cholesterol:
food of animal origin
336
Where is cholesterol found in the body?
In membranes, bound to phospholipids, and in blood by "atheromatous plaque".
337
Where are primary bile acids conjugated?
In the liver
338
What happens when primary bile acids enter the intestines?
7-OH is removed by microbial enzymes (deconjugation) and makes secondary bile acids. These goes into feces.
339
What is the biochemical function of Bile acids?
It is amphipathic, so it has one hydrophobic part (-CH3) and one hydrophilic part (-OH). This enables functions as:
1) emulsification of fats.
2) Solubilization and transport of lipids.
3) Participate in cholesterol metabolism, acting as hormones that alter the transcription of rate limiting enzymes.
4) Remove cholesterol from body through bile acid synthesis.
340
Biochemical role of Pyridoxine/Vit.B6:
1) Role in transamination.
2) Role in amino acid decarboxylation --> production of biogenic amines.
3) Role in heme synthesis
4) Role in nicotinic acid synthesis
5) Role in amino acid degradation
341
Deficiency of Pyridoxine/Vit.B6
3 different symptoms can be observed:
1) Neuropathic = not enouch neurotransmitter synthesis.
2) Anemic = due to low heme synthesis.
3) Pellagrous = due to low endogenous nicotinic acid synthesis.
342
How does the transaminases enzymes act?
act by transferring the amino group of an amino acid to the coenzyme to generate pyridoxamine phosphate (PALP). Pyridoxamine phosphate reacts then with an alpha-keto acid to form an amino acid and regenerates the original aldehyde form of the coenzyme PALP.
343
Tell something about degradation of carbs in ruminants!
Happens in rumen. Enzymes is frlom microbial origin. Ruminal microbes is e.g: bcteria, protozoa, fungi. A change in diet will result in change in microbes in rumen.
344
Tell something about VFA production in ruminants!
Microbes in the rumen ferment carbs into Volatile fatty acids. They are then absorbed in the rumen wall into the blood stream.
Influence frlom the food on VFA production is:
- Forage: starch will increase production, chewing will decrease production, low pH will produce proprionate.
- Roughage: cellulose and chewing will increase production, high pH will produce acetate.
345
Tell something about the absorption of VFA in ruminants!
by simple diffusion! If low pH, this will increase the absorption!
Also, facilitated passice diffusion with MCT-1 (mono carboxylate transporter) and HCO3-/SCFA(short-chain fatty acid) antiporter.
346
Tell something about VFA metabolism in ruminants!
- Acetate
- Proprionate
- Butyrate
347
Tell something about the formation of acetate in ruminant metabolism!
Acetate is a VFA fermented from carbs in the rumen by ruminal microbes. Acetate is activated to AcCoA and is then used in several reactions in the body.
In liver = used in TCA cycle, FA synthesis, Ketogenesis.
In adipose tissue and lactating mamamry gland= used in TCA, FA synthesis.
In muscle= used in TCA cycle.
348
Tell something about the formation of Proprionate in ruminant metabolism!
Proprionate is a VFA fermented from carbs in the rumen by ruminal microbes. Proprionate is activated to Proprionyl-CoA and is then used in several reactions in the body.
In liver= Propr.CoA is used in GNG and odd-carbon FA synthesis.
In adipose tissue= used in odd-carbon FA synthesis.
349
Tell something about the formation of Butyrate in ruminant metabolism!
Butyrate is a VFA fermented from carbs in the rumen by ruminal microbes. Butyrate is activated to Butyryl-CoA. Butyryl-CoA can be converted to 2x AcCoA. Butyryl-CoA can be used in several reactions in the body.
In liver= Butyryl-CoA is used in TCA, FA synthesis and ketogenesis.
In adipose tissue/lactating mammary gland= used in TCA, FA synthesis.
In muscle= used in TCA
In rumen= ketogenesis --> B-hydroxybutyrate!
350
Name some B-vitamins!
- Panthothenic acid/Vit.B5
- Thiamine/Vit.B1
- Nicotinamide/ Vit. B3
- Riboflavin/ Vit.B2
- Pyridoxine/Vit.B6
- Folic acid/Vit.B9
- Cobalamine/vit.B12
351
Source of Pantothenic acid:
Green vegetables and grains contains Pantothenic acid. Sources from animal products e.g: milk, meat, egg.
352
How is pantothenic acid/Vit.B5 excreted?
Excreted as pantothenic acid in urine and some in feces.
353
How can we get HSCoA from pantothenic acid/Vit.B5?
Pantothenic acid/Vit.B5 + 4 ATP + Cysteine --> HSCoA + CO2
354
What is the function of CoA-SH?
The SH-group (thiol-group) acts as a carrier molecule of acyl groups, forming activated thiol esters. The acyø-sulfur bond is a high energy bond
355
Deficiency of Panthothenic acid/Vit.B5:
found rarely, since the vitamin is supplied in almost all feeds and is also synthesized by microorganisms in the rumen and the intestines. However, some spp. show symptoms. In rats show lesions of the adrenal cortex. In black rats loss of hair color (a diet enough with panthothenic acid restores much of the black pigment). In young chicks and turkeys dermatitis can occur. Feathers are rough.
Pigs will show locomotor disturbances ("goose stepping"), and sometime paralysis. Dogs will have fatty liver, nervous symptoms and gastrointestinal disorders.
356
How is microbial proteins degradated in the ruminant?
Proteins (degradable) gets converted to Amino acids by protease enzyme. This AA can then be converted into alpha-keto acids (later VFA) and they can also contain ammonia.
Undegradable proteins can be degradated in abosmasum by pepsin, or in pancreas by trypsin. They are sort of "protected" by the microbes in the rumen. so they must be degradated else where. In young calves , abomasum also contains the enzyme "chymosin" which is the enzyme for milk digestion, beacuse the animal is just consuming milk the first time of life-
357
What is NPN agents?
Non-protein nitrogen. E.g urea, carbamide, ammonium salt, eaten by the ruminant. They can be converted into proteins by the microbes in rumen.
358
What is bypass proteins?
Proteins in ruminant by dietary intake, that bypass rumen and is not taken up by the microbes. Goes directly to the abomasum and intestines.
359
What is the endproducts of the metabolism of nitrogen containing compounds in ruminants?
bacterial protein, and ammonia (toxic) -> regulated by the ruminohepatic circulation.
360
WHat is toxicosis in ruminants?
Caused by overfeeding of NPN (non-nitrogen protein). Ammonia increases (hyperammoniaemia). Brain TCA cycle decreases, and this is the main cause for nervous system symptoms in ruminants. Treatment: acidify rumen by acetic acid.
361
Treatment of ketosis in ruminants:
give glucose intravenously, propylene glycol, glycerol.
362
Biochemical role of Cobalamine/Vit.B12
1) Intramolecular rearrangement:
- Homocystein converted to Methionine by "Homocystein methyltransferase" and methylcobalamine.
- Ribonucleotide DP converted to deoxyribonucleotide DP by "ribonucleotide diphosphate reductase" and DA cobalamine.
2) Role in GNG and beta-oxidation of odd chain FA synthesis.
363
Deficiency of Cobalamine/Vit.B12:
- Human: macrocytic hyperchromanemia = slower DNA syntheis, slower erythrocyte division, because of lack of intrinsic factor. Intrinsic factor is neccessary for absorption of Vit.B12.
- Ruminants: Normocytic and normochromic anemia = intesity og GNG is low.
- Pigs: Low vitality of piglets and slow growth.
- Birds: Mild normocytic anemia, decreased egg production, bad feed utilization and reproductive failures.
364
Background of ketosis in ruminants:
NEB (negative energy balance) is created in early lactation periods. GNG intensity is very high and uses all the OAC in this process. LL and B-oxidation intensity is very high and creates a lot of AcCoA, but there is no OAC to enter TCA, so AcCoA will produce ketone bodies wthout OAC present.
365
What kind of types of ketosis do we have in ruminants?
1) Primary ketosis = when alot of energy is needed, for dairy ketosis, pregnancy ketosis.
2) Secondary ketosis= When there is not enough energy uptake. Starvation/fasting, diabetes, GI disease.
366
Where is the location of lipid metabolism in ruminants?
In mammary gland, adipose tissue- "de novo".
367
What is the precursor for lipid metabolism in ruminants?
Butyrate, lactate - which becomes AcCoA. (Glucose becomes AcCoA in monogastric animals! remember this difference!)
368
Where can the ruminants get lipids from?
By diet, but the ruminants have a low lipid diet (2-5%). The diet contains high % of unsaturated C18 FA, and the rumen microorganisms will hydrogenate these FA to form Stearic acid (C18,0). Stearic acid will be absorbed and incorporated into depot fats.
The rumen microorganisms also synthesize long chain fatty acids and incorporate them into their membranes. These FA contains a high proportion of branched-chain FA derived from amino acids such as Valine, Leucine and Isoleucine, and of odd-numbered FA derived from synthesis from proprionate produced by fermentation in the rumen.
369
Biochemical role of pantothenic acid:
It is a carrier of acyl groups. Most important acids bound to CoA is:
Acetyl-CoA, Succinyl-CoA, Malonyl-CoA, proprionyl-CoA, Butyryl-CoA, Acetoacetyl-CoA, HMG-CoA.
Pantothenic acid is a component if coenzyme A and fatty acid synthase complex.
370
Primary bile salts from cholesterol that goes into the intestine is..?
Glycocholic acid and taurocholic acid
371
What are the two major metabolic pathways for detoxification of NH3 released during Aa catabolism?
- Urea cycle (mammalian liver)
- Uric acid cycle (avian liver)
Where toxic NH3 is converted into larger, non-toxic compounds and excreted in the urine.
372
What kind of detoxification methods does the body have?
Urea cycle, Oxidation (hydroxylation and conversion to acids and aldehydes), Reduction (hormones and other compounds are degradated and detoxified, e.g insulin which gets inactivated by reducing the disulphide bonds, Hydrolysis (hydrolytic cleavage of ester, amide glucoside linkage, e.g: glucosidic cardiac drugs AND Conjugation (compounds containing phenolic or alcaholic hydroxyl groups are conjugated to form glucoronides, e.g: some steroids and antibiotics. In this method, sulphuric acid is used for detoxification
373
Biochemical role of ascorbic acid/ Vit.C:
1) H-donator of "FH2 reductase": FH2 --> FH4
2) Reducing agent/electron donator: Fe3+ --> Fe2+
3) Antioxidant effect: H2O2 --> 2 H2O (H-donator) on free radicals.
4) Hydroxylation : OH-Pro/ OH-Lys: "Pro,Lys-hydroxylase" (in collagen synthesis)
374
Deficiency of ascorbic acid/Vit.C
Scurvy, because of decreased "Pro/Lys hydroxylase" activity which will decrease collagen synthesis. Symptoms will be capillary damage, small bleedings, weak bones (less osteoid matrix made), bleeding in gum.
Also: Decreased stress hormone synthesis, e.g heat stress in poultry and pig.
Also:: microcytic hypochromanaemia, beacuse of less Fe2+ which will lead to less intestinal absorption of iron to produce hemoglobin.
Also: Less FH2 synthesis ( FH2-reductase needs ascorbic acid) for DNA synthesis.
Also: after burning skin, ascorbic acid is needed to produce skin collagen.
375
What is muscle fibers composed of?
Consists of myofibrils which are extremely long and multinucleated cells. Their plasma membrane is known as sarcolemma.
376
What are myofibrils composed of?
two types of myofilaments: Myosin (thick) and actin (thin).
377
What is the name for the IC fluid surrounding the myofibrils in the muscle fibers? And what dows it contain?
sarcoplasm.
| It contains myoglobin, glycogen, creatine-P, glycolytic enzymes, amino acids, peptides and electrolytes.
378
What is the difference between red and white muscles?
Red are capable of continuously activity and have higher rate of O2 utiilization that white muscles. They have more and larger mitochondria, more myoglobin, more cytochrome.
Red muscles are dependent upon continuous energy production through mitochondrial oxidative reactions.
White muscles contains larger high-energy phosphate reserves and have higher capacity to derive energy from glycolytic reactions. It is organized to produce much ATP very fast by anaerobic processes.
379
What is the physiological regulator of muscle contraction?
Ca2+.
380
What happens in the muscles when it is in resting state and the levels of Ca2+ is low?
The interaction of actin and myosin is inhibited by the regulatory proteins "troponin and tropomyosin". Tropomyosin blocks the myosin binding sites on actin units. Nerve signals triggers the release of Ca2+. The released Ca2+ binds to troponin and causes conformational changes that are transmitted to tropomyosin and then to actin. Now, the myosin binding sites are free.
381
What happens when the heads of myosin interact with actin units?
actomyosin is formed
382
What is the precursor for the chemical energy that is transformed to the mechanical energy of contraction?
Since ATPase enzyme activity of Myosin is increased by F-actin, ATP is hydrolyzed and chemical energy is produced. ( Actin occurs in two forms: G-actin (globular) and F-actin (fibrous).
383
What is the "sliding of filament theory"?
movement of myosin heads towards the center of the sarcomere will lead to pulling the actin along and shortenong of the sarcomere. Actin filaments slide against myosin filaments.
384
What is the source of energy for contraction of muscles?
The amount of ATP found in the muscle are small in relation to the amount of chemical energy required to support contraction.
Skeletal muscle contains the high-energy compound "phosphocreatine". Creatine phosphokinase catalyzes the transfer of phosphoryl group from phosphocreatine to ADP to from ATP.
Main source of energy in red muscle: respiration.
Main source of energy in white muscle: glycolysis.
385
What is the difference between striated muscles and cardiac muscles?
The principles of metabolism apply to cardiac muscle the same as for striated muscles, but there are som differences:
1) Under normal conditions, the cardiac muscle which is rich in mitochondri shows high respiratory activity. The source of energy is FAs, but under anaerobic conditions: anaerobic glycolysis occurs: production of lactic acid -> cardiac pain.
2) In contrast with the striated muscle, where glycogen stores decrease significantly after starvation. , the cardiac glycogen level remains relatively stable.
3) The amino acid metabolism and protein synthesis is more intensive in cardiac muscle than in striated.
386
Tell me something about the Adipose tissue in the body!
Energy storage of mammals: Fat 80%, Proteins 20% and Carbs >1%. .
Adipose celles are specialized for the synthesis and storage of triacylglycerols, and for their mobilization into fuel molecules that are transported to other tissues by the blood.
387
What is the origin of the depot fat in the body?
Dietary fat which is absorbed and transported as plasma chylomicrons or lipoproteins. AND De novo synthesis, mayinly from Carbs and VFA. The energy comes from PPP.
388
WHat can of adipose tissue do we have in the body?
White adipose tissue for energy storage, padding material and heat isolation.
Brown adipose tissue for heat production (instead of ATP)
389
What happensif the amount of triacylglycerols increase?
- Hyperplasia= number of adipocytes increase
| - Hypertrophia= size of adipocytes increase.
390
Describe fat as energy source and store!
- Glycogen: 15 min energy supply (marathon runner)
| - Later: fat will be oxidzed
391
Tell me something about the brain!
consumes 20% of the total O2 used by the body, and 60-/5% of the glucose released from the liver.
It is storing Creatine-P and ATP.
The brain therefore reliies on a constant supply of glucose, O2 and blood to remove wate products!
392
What is blood brain barrier?
The brain has no significant stores of either glycogen or triacylglycerols. To provide energy for the brain, substrates must be able to cross the endothelial cells that line blood vessels in the brain, the "blood brainn barrrier". The blood brain barrier can be crossed by O2, Co2, NH3, Glucose(with GLUT 1 and 3) this is the main source of energy!, ketone bodies, some essential fatty acids and some electrolytes. Substrates that can NOT cross the barrier is Proteins and FAs, but they can cross over if they are shorter chain and unsat.FA!
393
Name some biochemical pathways in the brain!
-Glycolysis, Ketolysis
-Fat synthesis
-Non-essential Aa and protein synthesis
NO glycogen and fat store!
394
What is the reason for neural symptoms?
Detoxification of NH3. Alpha-KG + NH3 = Glutamate.
| Alpha-KG is removed from the TCA cycle, and the TCA cycle will be inhibited.
395
Tell something about the kindey!
It has Glutaminase enzyme-activity: Glutamine + H2O = Glucose + NH3.
NH3 is then converted to NH4+ which is excreted in the urine.
The glucose uptake in kidney needs transporter molecules: GLUT-2 and SGLT-1 and -2.
396
Biochemical pathways in the kidney:
- Glycogenesis
- Glycogenolysis
- Glycolysis
- GNG
- Ketolysis
- FA B-ox
397
Give a short review about the metabolism in ruminants!
Rumen: microbes! Carbs converted to VFA. NO glucose absorption - they are eatin by the microbes! Therefore, Ruminants have low blood sugar concentration (2-3 mmol/L)
Lipids: glycerols (VFA) and FAs which gets saturated by microbial lipids - absorbed in the intestines.
Proteins: ketoacids (VFA), NH3 from microbial aa + proteins --> digraded and absorbed in intestines. Therefore, NO actual need for essential Aas in Ru.
398
What happens during ammonia toxicosis?
Comes from non-nitrogen sources.
Treatment: giving acetic acid or easily digestible carbs -->VFA. The pH will go down, NH4+ will get produced, which leads to slower absorption and the risk of NH3 toxicosis decreases. This is called the ruminohepatic shunt.
399
How do we influence milk fat?
Give more roughage (hay), which increase chewing (alkaline) and the pH goes up. Them more acetate producing microbes increses. So the milk fat increases!
400
What happens during rumen acidosis?
It can be acute or subacute.
High amount of carbs (easily degraded) --> VFA production increases.
This will cause acidosis. Low pH will cause more dissociated VFA production and the VFA absorption increases.
