BIOCHEMISTRY FINAL REVIEWBy MiLo, Chim, Cú, Heo, Cá Trê, Bông

*13 vs 15 bỏ :3 đề mà ra là thí 2 câu đó :3*

1) Glycolysis is an almost universal pathway for extraction of the energy available from carbohydrates, shared among prokaryotes and eukaryotes, aerobes and anaerobes alike. By your understanding, discuss it and classify the 10 enzymes into six categories as you learnt.

Glycolysis is an almost universal pathway for extraction of the energy available from carbohydrates, shared among prokaryotes and eukaryotes, aerobes and anaerobes alike. In anaerobes, glycolysis is the only significant source of energy from carbohydrates. In aerobic organisms, considerably more energy can be harvested downstream from glycolysis in the citric acid cycle. Glycolysis produces energy in the form of ATP and NADH.

The intermediate products of glycolysis can be used for other pathways.-For instance, during active energy production, pyruvate, the product of

glycolysis, enters the citric acid cycle. In the absence of oxygen, fermentation converts pyruvate into lactic acid.

-When energy levels are high, glucose-6-phosphate, an intermediate of glycolysis, can enter glycogenesis to be stored as glycogen, or enter PPP to provide R5P for nucleic acid synthesis. PPP also produces GAP, an intermediate for glycolysis.

- Glyceraldehyde-3-phosphate, which is produced by photosynthesis, is also a glycolytic intermediate, so it can be directed from this anabolic pathway into glycolysis when energy is needed

-Glycogenolysis can degrade glycogen to Glucose-6-phosphate for Glycolysis to go on in situation where there is shortage of glucose.

(pathway glycolysis xem câu 7)

Step 1: Hexokinase: transferaseStep 2: phosphoglucoisomerase: IsomeraseStep 3: phosphofructokinase: transferaseStep 4: aldolase: lyaseStep 5: tri-isomerase: isomeraseStep 6: triose phosphate dehydrogenase: oxidoreductaseStep 7: phosphoglycerokinase: transferaseStep 8: phosphoglyceromutase: isomeraseStep 9: enolase: lyaseStep 10: pyruvate kinase: transferase

2) You have learnt methods to determine soluble protein, total soluble sugar, calcium content and enzymatic activity (Bromelain) in a sample. Choose one and describe the principle, chemicals, experimental design and analysis for the final result.

Hartree Lowry method to determine soluble protein in a sample.

1. Principle: The protein content in a sample is determine based on the quantitative reaction between copper ion and phosphomolybdic/phosphotungtic acid (Folin Cioucalteu reagent) with protein.

The blue color is form by 2 reactions:The bond formation between copper ion and nitrogen in peptide bonds.The reduction of phosphomolybdic/phosphotungtic acid by phenol residue of tyrosine and tryptophan amino acid in protein. The intensity of blue color is measure to determine the concentration of protein.

2. Chemicals:

0.1% albumin solution is used as standard. The standard should be the purified source of the protein to be quantified or the purified source of a protein with similar structure or in the same family. 0.1% albumin solution is prepared by taking exactly 0.1g of albumin and dissolving in water to get 100 mL of solution. Solution A contains Na2CO3 and NaOH (to create alkaline condition for reduction of phosphomolybdic/phosphotungtic acid).Solution B contains CuSO4.5H2O and Sodium citrate.Solution C is the mixture between solution A and B with ratio 49:1. Solution C is easily degraded so it must be freshly prepared. When solution loses it pale blue color, it no longer can be used.Folin Cioucalteu reagent should be preserved at 4°C and can be kept for 1 year. Fresh Folin reagent is yellow-orange. When the color turn yellow-green, it cannot be used.

3. Experimental design Prepare the sample: pulverize sample in blended or stone mortar Extract protein from the sample:

Take the pulverized sample into stone mortar or blended with distilled water. Grind down the sample and collect extracted solutionRepeat this step several times to extract as much protein as possible.

Construct standard curve:

Standard curve is the graph that shows the relationship between absorbance (OD value) and the concentration of protein in the solution. Standard curve is prepared with a series of test tube with increasing concentration of standard protein.

Quantify protein content:

Prepare 2 types of test tube:Test tube with 100-diluted extracted protein solution. 100-diluted solution is made by adding distilled water into 100mL volumetric flask containing extracted protein solution until the marked level is reached. Test tube with 10000-diluted extracted protein solution. 10000-diluted solution is made by adding 99mL distilled water into 1mL of 100-diluted solution. Add solution C and Folin reagent respectively into all test tubes including test tubes of standard curve. Keep test tubes for 10 minutes after each addition.Dilute all test tube by adding distilled waterMeasure at A750nm.

4. Analysis:

Use Excel to construct the standard curve and obtain the equation (y= ax +b) showing the relationship between OD value and concentration of protein. The y-axis is OD value and x-axis is concentration. Use the obtained equation to calculate protein concentration in extracted solution. The OD value in 100-diluted test tube is out of range so it is rejected. Insert the OD value into the standard curve equation to obtain the concentration. The amount of protein in the used pulverized sample is: n= (protein concentration) × 10000 (g)The amount of protein in the whole sample is: m= (n × (weight of the whole sample)) ÷ (weight of the used pulverized sample) (g)

3) The citric acid cycle is a central metabolic pathway that completes the oxidative degradation of fatty acids, amino acids, and monosaccharides. Based on your understanding, clarify the above statement.

The citric acid cycle is a central metabolic pathway that completes the oxidative degradation of fatty acids, amino acids, and monosaccharides.During aerobic catabolism, these biomolecules are broken down to smaller molecules that ultimately contribute to a cell’s energetic or molecular needs.

In early metabolic steps, From monosaccharides (a six-carbon sugar) in glycolytic pathway with the activity of the pyruvate dehydrogenase yield a two-carbon fragment -an acetyl groupAcetyl group is linked to a large cofactor known as coenzyme A (or CoA). Next, during the citric acid cycle that acetyl-CoA is oxidized to carbon dioxide with the reduction of the cofactors NAD+ and ubiquinone.

Fatty acids are source of Acetyl CoA

When a cell’s metabolic needs increase, free fatty acids enter the mitochondrion where the degradative reactions called Beta oxidation takes place.

In each round of Beta oxidation, a fatty acid is shortened by two carbon atoms and a release of a free acetyl-CoA molecule

Acetyl-CoA initiates the citric acid cycle Amino Acids

Typically, the amino group of an amino acid is removed in a deamination reaction. The remaining carbon skeleton is broken down to various a product depending on which of the twenty amino acids is undergoing catabolism. In some cases, the remaining carbon skeleton is broken down to acetyl-CoA or to pyruvate, which is then converted to acetyl-CoA. Alternatively, a citric acid cycle intermediate such as a-ketoglutarate may result. In all cases, the citric acid cycle plays a large role in breaking down the amino acid skeleton to carbon dioxide. For example, catabolism of lysine yields carbon dioxide and acetyl-CoA, while glutamate breaks down to a-ketoglutarate, carbon dioxide, and acetyl-CoA. Acetyl-CoA initiates the citric acid cycle.

4) You have learnt metabolic pathways of carbohydrate, protein, lipid and nucleic acid, show your overview by drawing the relation among their metabolism.

- Đề kêu draw thôi nhưng viết ra cho đọc để hiểu hình cho dễ thuộc dễ vẽ-Glucose is oxidized by glycolysis, an energy-generating pathway that converts it to pyruvate. In the absence of oxygen, pyruvate is converted to lactate. In the presence of oxygen, pyruvate is further degraded to form acetyl-CoA. Excess glucose is converted to its storage form, glycogen, by glycogenesis. When glucose is needed as a source of energy or as a precursor molecule in biosynthetic processes, glycogen is degraded by glycogenolysis.Glucose can be converted to ribose-5-phosphate (a component of nucleotides) and NADPH (a powerful reducing agent) by means of the pentose phosphate pathway. Significant amounts of energy in the form of ATP can be extracted from acetyl-CoA by the citric acid cycle and the electron transport system.Acetyl-CoA is generated from the breakdown of fatty acids and certain amino acids. When acetyl-CoA is present in excess, a different pathway converts it into fatty acids. That pathway is called lipogenesis.Glycerol also enters the Gluconeogensis in bypass step 2.

The process Gluconeogenesis is a process that builds up glucose from pyruvate and noncarbohydrate precursor such as lactate, amino acid, glycerol,…

Proteins in our body have nitrogen pool or amino acid pool which is a component of tissue protein and also produce NH3. NH3 enter Urea cycle.The urea cycle describes the conversion reactions of ammonia into urea. The urea cycle and CAC are linked (common connections are Fumerate, Oxaloacetate, alpha-ketogluterate)

5) Oxidative phosphorylation utilizes the chemical energy of these reduced molecules from glycolysis and C.A.C to produce ATP. How is your opinion and discuss it.Oxidative phosphorylation happen in mitochondrion, is the process by which electrons from the reduced cofactors NADH and ubiquinol are funneled in a stepwise manner to oxygen. Electrons flow much like electricity through the concomitant formation of a proton gradient. In the end the investment of reduced cofactors results in the production of ATP.Reduced electron carries NADH and ubiquinol are produced during glycolysis and citric acid cycle, as well as fatty oxidation pathway. During the cellular process of respiration oxidative phosphorylation utilize the chemical energy of these reduced molecules to produce ATP.

6) Pentose phosphate pathway is to provide reduced NADPH for synthetic reactions and ribose-5 phosphate for nucleic acid synthesis. By your understanding, discuss about oxidative and non-oxidative pathways.

The pentose phosphate pathway is an alternative metabolic pathway for glucose oxidation in which no ATP is generated.

It occurs in cytosol Two phases: oxidative phase and non-oxidative phase:a. Oxidative : NADPH is generated when glucose 6-phosphate is oxidized to ribose

5-phosphateb. Non-oxidative involves the isomerization and condensation of a number of

different sugar molecules: three-, four-, five-, six-, and seven-carbon sugarsDuring the remaining reactions of the pathway transketolase and transaldolase catalyze the interconversions of trioses, pentoses, and hexoses.The intermediates in this process that are useful in other pathways

i. fructose-6-phosphate (glycolysis)ii. glyceraldehyde-3-phosphate (glycolysis)

7) Gluconeogensis is the pathway to form new glucose from simpler molecules, called noncarbohydrate precursors, happening mainly in liver (~90%) and kidneys from pyruvate, lactate, glycerol, amino acids, and TCA cycle intermediates. The purpose is to make glucose when blood glucose level is low. By what you have learnt, choose one precursor and discuss how to result in glucose.

- In humans the main gluconeogenic precursors lactate, glycerol, alanine and glutamine. - Lactate produced by active skeletal muscle and erythrocytes(or red blood cells).

Erythrocytes lack mitochondria and can never oxidize glucose completely. In contracting skeletal muscle, the rate at which glycolysis produces pyruvate exceeds the rate at which the citric acid cycle oxidizes it.

- Lactate is a dead end in metabolism. It must be converted back into pyruvate before it can be metabolized.

- The lactate that enters the liver is oxidized to pyruvate. Pyruvate in the liver is converted into glucose by the gluconeogenic pathway. Glucose then enters the blood and is taken up by skeletal muscle.

- Gluconeogensis is the pathway to form new glucose from simpler molecules, called noncarbohydrate precursors, happening mainly in liver (~90%) and kidneys from pyruvate, lactate, glycerol, amino acids, and TCA cycle intermediates.Gluconeogenesis pathway consists of 11 steps which are reverse of glycolysis and there are 3 bypass steps- which use different enzymes and mechanisms compare with glycolysis. (cái b ng là so sánh bypass steps) (hình cho d hình dung Gluconeogenesis)ả ễ

8) When referring to the glycogen metabolism, three contents must be remembered as glycogenesis, glycogenolysis or regulation related to insulin, glucagon & epinephrine (adrenalin). Among them, choose one and discuss it.

General Intro about glycogen:• A carbohydrate• Large number of glucose by α-1,4 and α-1,6-glycosidic bonds

Storage of glycogen:• In muscle à forms as cytosolic granules with a diameter of 10 to 40 nm - the same

as the size of ribosome.• Concentration (liver cells) > concentration (muscle cells)• Total amount of glycogen in muscle cells > in the liver.• In the uterus, glycogen is stored during pregnancy to nourish the embryo.• In vagina, glycogen is secreted and then converted into lactic acid to maintain the

acidic environment in order to protect vagina from outside bacteria infections. • In kidneys, brain and white blood cells.

Glycogenesis• Excess of glucose• Glycogen is synthesized from glucose-6-phosphate.• Glycogen can either enter into pentose-phosphate pathway or contribute to the

process of glycolysis.Involves 3 steps:

1. Synthesis of glucose-1-phosphate2. Synthesis of UDP-glucose3. Synthesis glycogen from UDP-glucose

Glycogenesis is the formation of glycogen from glucose. Glycogen is synthesized depending on the demand for glucose and ATP (energy). If both are present in relatively high amounts, then the excess of insulin promotes the glucose conversion into glycogen for storage in liver and muscle cells. (It means that insulin inhibits glycogenolysis by inhibiting Glycogen phosphorylase enzyme activity.)

In muscle cells, glycogen degradation serves to provide an immediate source of glucose-6-phosphate for glycolysis, to provide energy for muscle contraction.

In liver cells, the main purpose of the breakdown of glycogen is for the release of glucose into the bloodstream for uptake by other cells. The phosphate group of glucose-6-phosphate is removed by the enzyme glucose-6-phosphatase, which is not present in myocytes, and the free glucose exits the cell via GLUT2 facilitated diffusion channels in the hepatocyte cell membrane.

9) Fatty acids are an important energy source as their yield over twice as energy as an equal mass of carbohydrate or protein. The two main pathways of fatty acid metabolism are β oxidation and fatty acid synthesis. β oxidation result in the formation of reduced cofactors and acetyl-CoA molecules, which can be further catabolized to release free energy. By what you have learnt, discuss a round of β oxidation and focus on the changing of each reaction, the energy yield, and name of enzymes.The activated fatty acid is called a fatty acyl-coenzyme A, or fatty acyl-CoA.

-In the first step of β oxidation, an acyl-CoA dehydrogenase catalyzes the oxidation of the acyl group, resulting the formation of a double bond between carbons two and three. The two electrons removed from the acyl group are transferred to an FAD prosthetic group. These electrons are transferred to ubiquinone through a series of electron transfer reactions.

-In the second step of β oxidation, a hydratase adds a molecule of water across the double bond produced in the first step.

-In the third step of β oxidation, another dehydrogenase catalyzes the oxidation of the hydroxyacyl group. In this case, NAD+ is the cofactor. The fourth and final step of β oxidation is called thiolysis. In this step, a thiolase catalyzes the release of acetyl-CoA from the ketoacyl-CoA.Energy yield: One round of β oxidation yields three products—one ubiquinol cofactor, one NADH cofactor, and one molecule of acetyl-CoA.

-During oxidative phosphorylation, 1 ubiqunol -> 2 ATP; 1 NADH -> 3ATP, 1 actyl-CoA -> 12ATP => total 17 ATP, and the net ATP is 15 (2 was used for fatty acid activation)

10) Call the names of below fatty acids and calculate the energy yield followed by equation of β oxidation

Name : acid panmitic Calculate the energy yield of this fatty acid:

- There are 16 carbon in this fatty acid (n=16), so the round number of it is: (n/2)-1 = (16/2) – 1 = 7 (rounds)

- One round of β oxidation produces the equivalent of 17 molecules of ATP.- In the 1st round, 2 ATP molecules were used for activation step.- The final product of complete β oxidation is an additional molecule of acetyl-CoA, which

are equivalent to12 molecules of ATP.- The total energy yield of this fatty acid is: (16/2 – 1 ) x 17 + 12 – 2= 129 ATP molecules.

Name: The name of this fatty acid is Linoleic acid (Linoleoyl-CoA)Calculate the energy yield of this fatty acid:

- There are 18 carbon in this fatty acid (n=18), so the round number of it is: n/2 – 1 = 18/2 – 1 = 8

- One round of β oxidation produces the equivalent of 17 molecules of ATP.- Double bonds at odd-numbered position cost 2 ATP molecules. - Double bonds at even-numbered position cost 3 ATP molecules.- In the 1st round, two ATP molecules were used for activation step.- The final product of complete β oxidation is an additional molecule of acetyl-CoA, which

are equivalent to12 molecules of ATP. - The total energy yield of this fatty acid is: 8 x 17 + 12 – 2 – 2 – 3 = 141 ATP molecules.

11) . About nitrogen metabolism, choose one and discuss a. - Essential & non-essential amino acids (mấy câu ở dưới khó wá, fải học urea

cycle hết nên đành chọn câu này ><)b. - Show out points where nitrogen metabolism links to glycolysis and C.A.Cc. - Urea cycle for NH3 deaminationd. - Mechanism to cause Gout disease

There are 20 amino acids used by human body. Amino acids are the building blocks of protein. Amino acids can be classified either as essential or non-essential. Essential amino acids are those that cannot be synthesized within our body and therefore, are essential in diet. Non-essential amino acids are those that can be synthesized from other amino acids or from substance in the diet and metabolism.

essential amino acidsarginine*♪ histidine ♪ isoleucine ♪ leucine ♪ lysine ♪ methionine* ♪ phenylalanine* ♪ threonine ♪ tryptophan ♪valine ♪non-essential amino acidsalanine ♪ asparagine ♪ aspartate ♪ cysteine ♪ glutamate ♪ glutamine ♪ glycine ♪proline ♪ serine ♪tyrosine♪

The amino acids arginine, methionine and phenylalanine are considered essential for reasons not directly related to lack of synthesis. Arginine is synthesized by mammalian cells but at a rate that is insufficient to meet the growth needs of the body and the majority that is synthesized is cleaved to form urea. Methionine is required in large amounts to produce cysteine if the latter

amino acid is not adequately supplied in the diet. Similarly, phenylalanine is needed in large amounts to form tyrosine if the latter is not adequately supplied in the diet.

12) Why do doers have to pay attention to the safety concern in the Biochemistry Lab? List out the hazardous factors that doers may encounter. List out all the concentration units that are commonly used in the Biochemistry Lab.Safety concern is very important in the Biochemistry Lab. When perform tasks in the lab, doers have to due with many toxic, erosive strong chemicals, as well as hard to handle machines, and electricity. The safety concerns are to help the doers yield the best result for their experiments in the safe way.-Toxic chemicals, strong acids, base.-Explosive, exothermal reactions.-Burning of chemicals-Fire-Electric shock-Production of hazardous gas.-Breakage of instruments.-Malfunctioning instruments.

Concentration units that are commonly used in the Biochemistry Lab:

-Molarity (M) M=n(mol solute )V (L solution)

-Molality m=n(molsolute )kg(solvent )

-Normality N=nmol equivalentsL solution

- μg/mLmọi người góp ý, chỉnh sửa bổ sung câu này dùm với :3

13) Show your acknowledgement and evaluation upon the presence and roles of Cholesterol ( in total, in HDL and in LDL forms) in human body

HDL cholesterol:

HDL stands for high-density lipoproteins, which is known as the "good" cholesterol.

HDL cholesterol carries the cholesterol away from arteries in into liver, thereby preventing heart disease.

A high HDL level helps to preserve brain cell function and prevent against mental decline in the elderly.

High levels of HDL are also used as a tool for diagnosing metabolic syndrome, thereby preventing heart attack.

HDL contains antioxidant molecules that may prevent LDL from being changed into a lipoprotein, which helps prevent heart disease.

LDL cholesterol:

LDL stands for low-density lypoproteins which is also known as the "bad" cholesterol for human health;

High levels of LDL in blood stream, it deposits the cholesterol into arteries, which can cause blockage and lead to heart attack.

LDL cholesterol an add to the build-up of plaque in arteries and increase risk of getting coronary heart disease.

In total:

- Total cholesterol is the sum of HDL cholesterol, LDL cholesterol and 20% of the triglyceride value. o Total cholesterol = HDL cholesterol + LDL cholesterol + (Triglyceride/5)

- In case of setting ( or low) amount of total cholesterol in body, we have to consider carefully that: o If high total cholesterol level is caused by high HDL level, we do not need to worry. Because

HDL cholesterol is good for our health. It transports cholesterol form the tissue back to the liver where it is secretes in the bile.

o If a high total cholesterol level is caused by high LDL level, we need to pay more attention to our diet, our inputs in order to avoid heart disease, obesity…

In brief, both HDL and LDL play an important role in human body. Total cholesterol has the relation with HDL and LDL. The higher or lower of HDL and LDL affects the level of total cholesterol, which has effects on human body.

14) What are the most commonly known functionalities of fatty acids in human body? First, fatty acids are building blocks of phospholipids and glycolipids-

amphipathic molecules that are important components of biological membranes. Second, many proteins are modified by the covalent attachment of fatty acids,

which targets them to membrane locations. Third, fatty acids are fuel molecules. They yield over twice as much energy as an

equal mass of carbohydrate or protein. They are stored as triacylglycerols (also called neutral fats or triglycerides), which are uncharged esters of fatty acids with glycerol. Fatty acids mobilized from triacylglycerols are oxidized to meet the energy needs of a cell or organism.

Fourth, fatty acid derivatives serve as hormones and intracellular messengers. Cholesterol is a lipid with a hydrocarbon tail linked to the steroid (built from four linked hydrocarbon rings) at one end, and a hydroxyl group attached at the other end. It is a common component of cell membrane and a precursor for the synthesis of other steroid such as vertebrate sex hormones (estradiol and testosterone). Intracellular messengers are generated by activated receptors on cell membrane to transmit information into the cell, diacylglycerol and triphosphoinositol are examples of intracellular messengers.

15) What is the closed correlation of cholesterol and fatty acids? Cholesterol and fatty acids are 2 forms of lipid, which circulate in your bloodstream. - They are both necessary for life itself. Cholesterol is necessary for building, maintaining key parts of our cells and making several essential hormones (estrogen, progesterone, testosterone…). While triglycerides, which are chains of high-energy fatty acids, provide energy for tissues to function. - High levels of both cholesterol and fatty acids can cause heart disease. - Cholesterol includes HDL, LDL and total cholesterol. Total cholesterol is the sum of HDL, LDL and 20% triglycerides of value. It is clarified by formula: Total cholesterol= HDL cholesterol + LDL cholesterol+ Triglycerides/5- Triglycerides has 2 sub-classes, which relate to cholesterol

16) What are amino acid catabolism and deamination? Amino acid catabolism: the breaking down of amino acids into carbon skeleton and amino moiety (A specific segment of a molecule) in order to generate ATP. There are 3 major steps of AAs catabolism:

1. Removal of amino group, deamination, by:- Transamination: Transfer of amino group to a-ketoglutarate yielding glutamate

- Oxidative deamination: removal of amino group from glutamate to release ammonia

- Other deamination processes.

2. Urea Cycle: Conversion of NH3 to urea for excretion3. Metabolic break down of carbon skeleton to generate common intermediates that can be

catabolized to CO2 or used in anabolic pathways to be stored as glucose or fat.

Amino acid deamination: Deamination is the process by which amino acids are broken down if there is an excess of protein intake. The amino group is removed from the amino acid and converted to ammonia. The rest of the amino acid is made up of mostly carbon and hydrogen, and is recycled or oxidized for energy.

Deamination is also an oxidative reaction that occurs under aerobic conditions in all tissues but especially the liver. During oxidative deamination, an amino acid is converted into the corresponding keto acid by the removal of the amine functional group as ammonia and the amine functional group is replaced by the ketone group. The ammonia eventually goes into the urea cycle.

17) Show the general outline chemistry of deamination

18) Discuss about roles of the amino acid carbon skeletons in the deamination process. The carbon skeletons of the α-ketoacids are converted to common intermediates of energy producing, metabolic pathways. These compounds can be metabolized to CO2 and water, glucose, fatty acids, or ketone bodies by the central pathways of metabolism.The carbon skeletons of the α-ketoacids, from deamination, results in the formation of seven products: pyruvate, acetyl-CoA, acetoacetyl-CoA, α-ketoglutarate, suc-CoA, fumarate andoxaloacetate (Kreb Cycle). Amino acids are divided into glucogenic and ketogenic amino acids:

Ketogenic amino acids (leucine and lysine) lead to the formation of acetyl-CoA and acetoacetyl-CoA.

Glucogenic amino acids (serine, threonine, cysteine, methionine, aspartate, glutamate, asparagine, glutamine, glycine, alanine, valine, proline, histidine and arginine) include those that lead to the formation of the remaining five products – pyruvate, α-ketoglutarate, suc-CoA, fumarate or oxaloacetate 

Amino acids called keto- and glucogenic amino acids (isoleucine, phenylalanine, tyrosine and tryptophan) have two degradation products – one of them being glucogenic and second one ketogenic.

The following overview shows degradation products of particular amino acids:1) Acetyl-CoA and acetoacetyl-CoA – Lys and Leu are purely ketogenic amino acids, some other amino acids (Phe, Tyr, Trp, Ile) provide glucogenic and ketogenic degradation products2) α-ketoglutarate – five-carbon amino acids – Glu, Gln, Pro, Arg a His3) Suc-CoA - nonpolar amino acids – Met, Ile a Val4) Fumarate - Phe, Tyr5) Oxaloacetate – four-carbon amino acids – Asp a Asn6) Pyruvate – Cys, Ala, Ser, Gly, Thr, Trp

Hình cho mọi ngừoi dễ hình dung thui nha

19) ATP synthesis via oxidative phosphorylation occurs via two separate systems in the mitochondrion. What are they? Briefly summarize the involving steps in the ATP synthesis.

Oxidative phosphorylation is the synthesis of ATP from ADP (phosphorylation), that occurs when NADH and FADH2 are oxidized throughout electron transport chain (oxidation).Inner membrane of mitochondria is the site of oxidative phosphorylation in eukaryotes A. Oxidation step: electron transport chain NADH + H+ + O2 NAD+ + H2OFADH2 + O2 FAD + H2OB. Phosphorylation stepADP + Pi ATP

The electron transport chain is series of protein complexes embedded in mitochondrial membrane.

This chain is consisting of 4 complexes and ATP Synthesis. 4 complexes are:- NADH (Complex I)- FADH2 (Complex II) - Cytochrome b-c (Complex III)- Cytochrome oxidase (Complex IV) ATP synthesis via oxidative phosphorylation occurs via two separate systems in the

mitochondrion.1. Electrons are “transported” via numerous membrane-bound carriers from NADH to O2. During these reactions, a proton gradient is formed across the mitochondrial inner membrane.2. The proton-motive force in the gradient is then harnessed to produce ATP.

- Mitochondrial structure plays a critical role in forming and utilizing the proton gradient to synthesize ATP.

- Protons are “pumped” from the matrix across the inner membrane into the intermembrane space.

- ATP is synthesized in the matrix, as protons flow back through the membrane.

Briefly summarize the involving steps in the ATP synthesis (1)A complex channel protein known as ATP synthase, also called complex V, is the final enzyme in the oxidative phosphorylation pathway. It allows the controlled flow of protons back into the matrix while, at the same time, harnessing the free energy of proton flow to convert ADP and phosphate into ATP. ATP can be thought of as a form of portable free energy, or an energy currency, that can be used for energy-requiring reactions elsewhere in the cell. This is analogous to water flowing through the turbines of a dam to generate electricity.

NADH: The flow of 2 e‐ (to reduce1 oxygen atom O) through complexes I, III & IV results in the translocation of 3 ATPsFADH2: The flow of 2 e‐ through complexes II, III & IV results in the translocation of 2 ATPs

Briefly summarize the involving steps in the ATP synthesis (2)Synthesis of ATP is coupled with the oxidation of NADH and the reduction of O2. There are three key steps in this process:

1. Electrons are transferred from NADH, through a series of electron carriers, to O2. The electron carriers are proteins embedded in the inner mitochondrial membrane.2. Transfer of electrons by these carriers generates a proton (H+) gradient across the inner mitochondrial membrane.3. When H+ spontaneously diffuses back across the inner mitochondrial membrane, ATP is synthesized. The large positive free energy of ATP synthesis is overcome by the even larger negative free energy associated with proton flow down the concentration gradient.

20) Briefly discuss about relation of the Pentose phosphate pathway (PPP) and Glycogen metabolism.

Both glycogen metabolism and pentose phosphate pathway is considered as glucose anabolism processes. The relation of PPP and glycogen metabolism is briefly discuss by the following figure.

Glucose-6-phosphate is material for both glycogenesis (glycogen anabolism) and PPP. Furthermore, glycogenolysis (glycogen catabolism) process has final product is glucose-

6-phosphate this process give material for the PPP.In summary, the relation between PPP and glycogen metabolism is briefly discussed through glucose-6-phosphate.