30/08/2022
In formation for medicine students 👨🔬👩🔬.....
Biochemistry....
The topic of metabolism...
1.carbohydrates metabolism:-
1.cellular respiration:-
its importance is to produce ATP ⚡that the cell energy shape or currency 💲💲, it's divides into 3 steps 🪜🪜🪜....
1.glycolysis:-
that's the process of breakdown the glucose(6 carbon atoms ⚛️⚛️⚛️⚛️⚛️⚛️) molecule into 2 molecules of pyruvate (3 carbon atoms ⚛️⚛️⚛️) in the aerobic pathway in presence of O2 or 2 lactate in absence of O2 that is with also 3 carbon atoms ⚛️⚛️⚛️.
Results:2 pyruvate or 2 lactate+2 ATP+2NADH.
Site:the cell cytoplasm.
2.Kreb's cycle 🤯🌀:-
Site:the mitochondrial matrix
Steps:that pyruvate will enter to this cycle in present of oxygen after the oxidation step 🪜 when the 2 pyruvate converts into acetyl COA (3 carbon atoms ⚛️⚛️⚛️) when the 2NAD convert to 2 NADH,this acetyl COA is condensed with oxaloacetate that will make it enter the cycle that will over with oxaloacetate after many reactions with different enzymes.
Results:2ATP,2FADH2,NADH6.
3.Electrone transport chain ⛓️⛓️ (oxidative phosphorylation):-
The NADH & FADH2 that results from glycolysis and Kreb's cycle are convert to ATP ⚡🔥 by this chain.
Site:the mitochondria
Steps 🪜🪜🪜......
In the mitochondrial inter membrane space 🌌🌌 there are special proteins will form the chain ⛓️,they are taking the electrons of the NADH & FADH2 and move them between each other protein during this process there are protons H+ out from the matrix to the inter membrane space 🌌🚀 then they will accumulate and be toooooooo much but protons are hate the crowded places 😑😑💔then the ATP ⚡ synthase enzyme return them to the mitochondrial matrix and form the ATPs,this step will give us the biggest number of ATP ⚡⚡🔥
Results:10 NADH from steps 1and2 and every one give us about 3 ATP ⚡⚡⚡so they will give us 30 ATP,2FADH2 they will give us about 4 ATP ⚡⚡⚡⚡,4 ATP from steps 1 and 2,so the total number of ATP IS 38 ATP (⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡⚡).
2.The glycolysis:-
is complete oxidation of the glucose into two molecules of pyruvate, it's happen in the cytosol it's complete in the following steps....
1.glucose converts into glucose 6 phosphate by glucokinase or hexokinase enzymes so there's phosphorylation reaction.(irreversible)
2.the glucose 6 phosphate converts into fructose 6 phosphate by isomerase enzyme.(reversible)
3.the fructose 6 phosphate converts into fructose 1,6 bisphosphate by aldolase enzyme(irreversible)
4.the fructose 1,6 bisphosphate converts into DHAP by mutase enzyme then it will converts into glyceraldehyde 3 phosphate by isomerase enzyme.
5. The glyceraldehyde 3 phosphate converts into 1,3 bisphosphoglycerate by enzyme of GLA3P DH
6.1,3 bisphosphoglycerate converts into 3 bisphosphoglycerate by kinase enzyme.
7.3 bisphosphoglycerate converts into 2 bisphosphoglycerate by isomerase enzyme.
8.2 bisphosphoglycerate converts into phosphoenolpyruvate by enolase enzyme,then it will converts into pyruvate by enzyme of pyruvate kinase.
3.Glycogenesis:-
after we use the glucose, there are some amount of it that is store many body cells but with large amount in the following cells:-
1.liver cells
2.muuscle cells
They're store it as glycogen because it's needed to large space 🌌 to storage in its natural shape .
3.adipose cells: they store it as fats .
Other reason that explains the glucose can't store in its natural shape is..
The glucose is unstable substance can enter any reaction in the body.
Steps:-
1.the glucose converts into glucose 6 phosphate by glucokinase (liver) or hexokinase (muscles) enzymes,the ADP converts into ATP.
2.glucose 6 phosphate converts to glucose 1 phosphate by phosphogluco mutase enzyme,we must replace the glucose from position 6 to position 1 by the same enzyme.
3.adding of UDP molecule to glucose 1 phosphate by UDP glucose pyrophosphatase enzyme to form the UDP glucose that is the building blocks of the glycogen but 😳😳💔..
They can't stuck with each other to form the glycogen directly,they must connect to a branch of glucose that is already formed.
The primer:it is a small glycogen that is related to UDP glucose.
4.the glycogenin enzyme that is can connect between about 10 UDP glucose(they are form the primer) the glucose will replace from position 1 to 4 the bond is called alpha 1,4 glucosidic bond ,then the primer stuck with the UDP glucose.
5.the glycogenin enzyme form straight bond but the glycogen bond is with branches so.....
The branching enzyme 😎😎🔥 cut about 8 glucose atoms ⚛️⚛️⚛️⚛️⚛️⚛️⚛️⚛️ and add them to the 6th carbon in position 1 to form alpha 1,6 glucosidic bond and form the glycogen 🥱🥱🥵🥵.
This process will repeat 🔁 and repeat 🔁 by the glycogenin and the branching enzyme 😎🫀♾️.
The function of glycogen in the cells:-
1.liver cells:the glycogen is store till the need situation like fasting state it's store for 24 hours.
2.muscle cells:for it self for the exercise.
4.absorption of the carbohydrates:-
1.there're 4 glucose transporters 1,2,3,and4, they are divide into 2 types:
1.Insullin dependant:that is only glucose transporter 4.
2.Insullin non dependant:they are glucose transporters 1,2,and,3.
Sites of glucose transporters insulin non dependant:KRBILA is an abbreviation of these sites...
K: kidney,R:RBCs and the eye 👁️ retina,B:the brain 🧠,I:the intestines,L:the lung and the liver,A:the adrenal medulla.all those transporters are called the glutes they are found in the following sites 🪑:-
1.in the RBCS.
2.in the intestine,liver,and kidney.
3.in the brain 🧠.
Steps 🪜🪜 of the absorption:-
1.the monosaccharides in the small intestine lumen must transport to the cell wall 🧱.
2.the sodium-glucose co transport channel enter the glucose and sodium into the cell,this transport is active so it's needed to energy.
3.water molecules are love 😘💕 the sodium so they will follow it to the cell,but 😕the cell may ruptured by this high concentration of water 💦💦 molecules.
4.in the other side there's Na+-K+pump ⛽⛽ that will out the sodium atoms ⚛️⚛️⚛️⚛️⚛️ and enter the potassium atoms ⚛️⚛️⚛️⚛️⚛️⚛️⚛️.
5.the sodium will enter the blood circulation,by the glucose transporter 2 the glucose will enter the blood circulation too by the portal vein to the liver then to the all body 👅👁️🫀🧠👃👂🫁🩸🦷✋🦵🦶🦴.
5.glycogenolysis:-
Definition:it is the process of breakdown the glycogen in the need situation.
Note 🎶:the glycogen is made up of many glucose molecules in two bonds alpha 1,4 glucosidic bond that attached by branch of glucose to alpha 1,6 glucosidic bond.
Steps 🪜:
1.the glycogen phosphorylase enzyme works only in the straight bonds (alpha 1, 4 glucosidic bond) it separate every glucose as glucose 1 phosphate till the 4 residue glucose molecules.
2.the debranching enzyme separate 3 of the 4 residue glucose molecules and connect them to a branch and make the phosphorylase keep working in the alpha 1, 4 glucosidic bond.
3.the last glucose molecule that attached to the alpha 1,6 glucosidic bond is separated by the debranching enzyme so it is with the following functions....
1.separation of 3 of the 4 glucose residue molecules (transferase activity).
2.breakdown of the last glucose molecule in the alpha 1,6 glucosidic bond (glucosidase activity).
Note 🎶:each one glucose molecules converts⁴ into glucose 1 phosphate...
The glucose 1 phosphate fate:
1.in the liver:-
The glucose 1 phosphate converts to glucose...
1.glucose 1 phosphate converts to glucose 6 phosphate by the phosphogluco mutase enzyme.
2.glucose 6 phosphate converts to glucose by glucose 6 phosphatase,this glucose enter the blood circulation.
2.in the muscles 💪🏼:
The glucose 1 phosphate converts to glucose 6 phosphate by phosphogluco mutase enzyme that is enter the 1st step 🪜 of the glycolysis by the hexokinase enzyme.
Sum: glycogen _glucose 1 phosphate _glucose 6 phosphate (in the muscles)_glucose.
6.Pentose phosphate pathway (HMP shunt):-
1.why?🤔
1.the NADPH formation,but why 🤪🌚??ok,ok 🤣 hold on man 😏😑, it's for...
1.FA synthesis
2.protect the cell from the oxidative stress and the free radicals.
Understand 😏😏??
I'll give you another reason,hold up 🌚😏..
2.the ribose-5-phoshate formation for the formation of DNA 🧬 &RNA.
2.where?🤔
It's happen in about 3\4 of the body 👅👁️ cells specially..(HMP meaning)
1.liver(hepatic)
2.mammary gland(mammary gland)
3.adrenal gland(cortex)(periphery)
3.)How?¿🤔وتاني 🤔
It's complete in two phases:-
1.oxidative phase:
with irreversible reactions as the followings:-
1.the glucose 6 phosphate come from the glycolysis and converts to 6-phosphogluconolactone by glucose 6 phosphate DH enzyme that is do oxidation reaction,in this reaction the 1st NADPH will form.
2.the 6-phosphogluconolactone converts to 6-phosphogluconate by gluconolactonase enzyme.
3.the 6- phosphogluconate converts to its isomer that is Ribulose-5-phosphate by 6- phosphogluconate DH enzyme that do the 2nd oxidation reaction and form the 2nd NADPH.
Note 🎶:all the previous reactions are irreversible reactions and all molecules with 6 carbon atoms ⚛️⚛️⚛️⚛️⚛️⚛️ except the Ribulose-5-phosphate that with 5 carbon atoms ⚛️⚛️⚛️⚛️⚛️ the missing one is out as CO2 in the second 🥈 oxidation reaction 🤝🏼.
The end 🔚 of the oxidative phase 🤝🏼🔒.
2.non oxidative phase:-
With reversible reaction as the followings....
1.the Ribulose-5-phosphate by..
1.Isomeras enzyme: converts to Ribose-5-phoshate that's we need it 🥳🥳🥳🎉🎊.
2.Epimerase enzyme: converts to xylulose-5-phosphate .
Transketolase &transaldolase: they are enzymes share the carbon atoms ⚛️⚛️ (ketolase)⚛️⚛️⚛️(aldolase)...
2.by transaldolase enzyme the ribose-5-phoshate converts to Glyceraldehyde 3 phosphate and the xylulose-5-phosphate converts to sedoheptulose-7-phosphate.
3.by transaldolase enzyme the glyceraldehyde 3 phosphate will convert to fructose 6 phosphate,and the sedoheptulose-7-phosphate will convert to Erythrose 4 phosphate.
4.the Erythrose 4 phosphate will form another xylulose-5-phosphate by reversible reaction of conversation of it to fructose 6 phosphate,so..
By transketolase enzyme the Erythrose 4 phosphate converts to fructose 6 phosphate, and the xylulose-5-phosphate converts to Glyceraldehyde 3 phosphate.
Note 🎶:all the previous reactions are reversible reactions with3,4,5,6,and7 carbon atoms.
I have a question ❓❓🔥😏🌚🙂🙂...
In the 1st step 🪜 of the non oxidative phase we have form the ribose-5-phoshate that we want it from this pathway,why are we moving on the reactions??
Because these reactions are reversible reactions can form their opposites according to the body need.
7.urea cycle:-
Function:When our body breakdown the amino acids with extra amount and form the amonia that is toxic and can't be removed in its original shape,it must converts it to a molecule that's less toxic and can be removed that is the UREA 😎🙂via the urea cycle 🤯...
Steps: it's complete in two parts in different sites 🪑🪑...
1\part inside the mitochondria:-
A carbon dioxide atom ⚛️ added to the amonia in the present of carbamoyl phosphate synthatase, they are convert to carbamoyl phosphate that is from 2 bicarbonate.
2\part inside the cytoplasm:-
1.the carbamoyl phosphate will stuck with a non essential amino acid in the cytoplasm that called ornithin in present of the ornithin transcarbomylase enzyme, they are convert to citrulline.
2.the citrulline will stuck with the aspartate in present of the arginino succinate synthatase and convert to arginino succinate.
3.the arginino succinate converts to arginine and out the fumarate in present of arginino succinase enzyme .
4.the arginine by arginase enzyme converts to ornithin 🥳❤️❤️🥺and out the UREA 🥳🔥.
Then the urea enter the blood and then to the kidney that will out it with the urine in the bathroom 🛁🤣🤣🤣💔.
Note 🎶:every synthatase enzyme needed to ATP to work and it will synthesis the molecule that is named with.
The End 🔚🥳.
8.fructose metabolism:-
It's a monosaccharide (the simplest carbohydrate) so we can't break it down to simpler molecules.
Sources: fruits 🍓🍒🍎🍉🍑🍊🥭🍍🍌🍋🍈🍏🍐🥝🫒🫐🍇🥥,honey 🍯,and others,it was using as a sugar for some foods and drinks.
Metabolism problem: it's not familiar to the body so it is going to convert it to the glucose that is familiar to it and it has its metabolic pathway (glycolysis).
Steps 🪜🪜:-
1.In the liver cells:that is with most of fructose in the body.
1.the fructose converts to fructose 1 phosphate by the hexokinase enzyme,the ATP converts to ADP.
2.the fructose 1 phosphate converts to DHAP and GLA by fructose 1 phosphate aldolase enzyme.
3.the GLA converts to GLA3P by triose kinase enzyme,then it will enter the glycolysis in the 4th step.
2.In the muscle cells:the fructose converts to glucose 6 phosphate by hexokinase enzyme.
The end 🔚🥳.
9.galactose metabolism:-
It's a monosaccharide like the fructose and glucose,and it's the epimer of the fructose ,but they differ in the OH group position.
Sources: milk 🥛 and some dairy 🧈, fruits 🍓🍒🍎🍉🍑🍊🥭🍍🍌🍋🍈🍏🍐🥝🫒🫐🍇🥥,and vegetables 🍅🌶️🥕🍠🧅🌽🥦🥒🥬🫑🥑🍆🧄🥔🌰.
Site:in the liver .
Steps 🪜🪜....
1.the galactose converts to galactose 1 phosphate be galactokinase enzyme.
2.the galactose 1 phosphate converts to glucose 1 phosphate by galactose 1 phosphate uridyl-transferase enzyme.that happen in the presence of UDP glucose that converts to UDP galactose.
3.the glucose 1 phosphate converts to glucose 6 phosphate by phosphogluco mutase enzyme,the glucose 6 phosphate enter the 1st step 🪜 of glycolysis.
4.the UDP galactose converts to UDP glucose by epimerase enzyme.
The End 🔚🥳.
nagm
