1. Give TWO (2) examples of sterols responsible for the synthesis of Vitamin D. How these sterols can be converted into Vitamin D? 2. Geranylgeranyl pyrophosphate (GGPP) is a universal precursor for all diterpene/diterpenoids. How GGPP is converted to linear, monocyclic, bicyclic and tricyclic diterpene/diterpenoids? Explain.

1. Give TWO (2) examples of sterols responsible for the synthesis of Vitamin D. How these sterols can be converted into Vitamin D? 2. Geranylgeranyl pyrophosphate (GGPP) is a universal precursor for all diterpene/diterpenoids. How GGPP is converted to linear, monocyclic, bicyclic and tricyclic diterpene/diterpenoids? Explain.

Biochemistry

6th Edition

ISBN:9781305577206

Author:Reginald H. Garrett, Charles M. Grisham

Publisher:Reginald H. Garrett, Charles M. Grisham

Chapter27: Metabolic Integration And Organ Specialization

Section: Chapter Questions

Problem 20P: Figure 27.3 illustrates the response of R (ATP-regenerating) and U (ATP-utilizing) enzymes to energy...

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1. Explain the reaction mechanism involved how glucogenic amino acids can yield either a pyruvic acid or an oxaloacetic acid. In what pathway will pyruvic or oxaloacetic acid be used and why is this pathway important? 2. Discuss the reaction mechanism involved how the -NH2 groups of amino acids are being metabolized. 3. Explain why gluconeogenesis under conditions of starvation or diabetes breaks down body proteins. Complete answer please. Thank you. |
1.Why do you think glutathione occurs in a concentration as high as glucose? 2.Explain why glutathione must be transported from cytosol to mitochondria. 3.Explain why glutathione can confer therapeutic benefit when taken orally.
3. (a) Wakil's pioneering studies on fatty acid synthesis included the crucial observation that bicarbonate is required for the synthesis of palmitoyl-CoA. He was surprised to find that very low levels of bicarbonate could sustain palmitate synthesis; that is, there was no correlation between the amount of bicarbonate required and the amount of palmitate produced. Later he also observed that 14C-labeled bicarbonate is not incorporated into palmitate. Explain these observation (b) The condensation reaction catalyzed by B-ketoacyl-ACP synthase generates a 4-carbon unit by combining a 2-carbon unit with a 3-carbon unit and loss of CO2. Write with structural formulas how this occurs. What is the thermodynamic advantage of this way of generating the 4-carbon unit over combining two 2-carbon units as occurs fatty acid oxidation or ketone body reactions" (c) Decide where labeled carbon atoms will be found in palmitate if (i) (3-1“C)malonyl-SCOA or (ii) (2- 14C)malonyl-SCOA are used.
19. Which statement is TRUE of sphingolipid synthesis? 1.All of the carbon atoms of palmitate and serine are incorporated into sphingosine. 2CDP-sphingosine is the activated intermediate. 3CO2 is produced during the synthesis of ceramide from palmitate and serine. 4Glucose 6-phosphate is the direct precursor of the glucose in cerebrosides. 5Phosphatidic acid is a key intermediate in the pathway.
16. The overall reaction for the glycolysis reaction is C6H₁2O6(aq) + 2NAD+ (aq) + 2ADP³(aq) + 2HPO(aq) + 2H₂O(1) 2CH3COCO₂ (aq) + 2NADH(aq) + 2ATP4 (aq) + 2H3O+ (aq). What is A,G at chemical equilibrium?
1. Prostaglandins are a class of eicosanoids, fatty acid derivatives with a variety of extremely potent actions on vertebrate tissues. They are responsible for producing fever and inflammation and its associated pain. Prostaglandins are derived from the 20- carbon fatty acid arachidonic acid in a reaction catalyzed by the enzyme prostaglandin endoperoxide synthase. This enzyme, a cyclooxygenase, uses oxygen to convert arachidonic acid to PGG2, the immediate precursor of many different prostaglandins. (a) The kinetic data given below are for the reaction catalyzed by prostaglandin endoperoxide synthase. Focusing here on the first two columns, determine the Vmax and Km of the enzyme. (b) Ibuprofen is an inhibitor of prostaglandin endoperoxide synthase. By inhibiting the synthesis of prostaglandins, ibuprofen reduces inflammation and pain. Using the data in the first and third columns of the table, determine the type of inhibition that ibuprofen exerts on prostaglandin endoperoxide…
1. Draw the products that would be produced from phospholipase C cleavage of a glycerophospholipid with a phosphoserine head group, an alpha linoleic acid attached to C2 of the glycerol and a linoleic acid attached to the C3 of glycerol. Draw these products at pH=1. Be sure to number the fatty acid carbons in your products
2. Consider a preparation that contains all of the enzymes and cofactors needed for fatty acid biosynthesis from added malonyl-CoA and acetyl- COA. a. If [2-H) acetyl-CoA (labeled with deuterium) H-c-C-COA and an excess of unlabeled malonyl-CoA are added as substrates, how many deuterium atoms are incorporated into each palmitate? What are their locations in the palmitate structure? (Draw an expanded structural formula for palmitate showing the locations of the deuterium atoms (as drawn in acetyl-CoA above). Explain your answer.
Help filling in the blanks: Pyridoxal phosphate, PLP, is produced from pyridoxine or vitamin B6. PLP is considered a/an [1C/2C/acyl/amino/carboxyl] carrier. In transaminases, PLP forms a [Schiff base/acetal/phosphoanhydride/condensation] with an amino acid and causes the [a- amino/a-carbon/a-carboxyl] to become [electrophilic/nucleophilic] allowing replacement of the amino group on the amino acid with a ketone. PLP is also used by several other enzymes that work on amino acids because in forming a covalent bond with amino acids it provides for an opportunity for nucleophilic attack and because PLP is conjugated, the cofactor is able to [delocalize/transfer/reduce/stabilize] pi electrons in the substrate and thus [stabilize/delocalize/transfer/reduce] the transition state of the reaction. Production of citrulline occurs in the [cytosol/mitochondrial matrix] while the rest of the urea cycle occurs in the [cytosol/mitochondrial matrix]. Urea is produced in the…
In the first cycle of fatty acid synthesis via the acyl carrier protein system, the acetyl group on fatty acid synthase condenses with the malonyl-ACP complex. Draw the structure of the products of this reaction. · Represent ACP by R1. Do not include the free synthase in your drawing. • Be sure to include charges on atoms at pH = 7. • Draw one structure per sketcher. Add additional sketchers using the drop-down menu in the bottom right corner. · Separate multiple products using the + sign from the drop-down menu. ? n []
2. Fatty acid synthase is a multi functional protein which carries out the synthesis of fatty acids from malonyl-CoA and acetyl-CoA building blocks. The enzyme contains two reactive sulfhydryl groups, one on the long arm of the acyl carrier protein (ACP), the other on the b-keto-acyl ACP synthase domain (KS). These two -SH groups are shown schematically in the figure below. a) Draw the structure of the complex that results from“charging"with the malonyl-CoAand acetyl CoA substrates. b) Following condensation of the malonyl and acetyl groups, ab-ketobutyrylgroup bound to the enzyme is generated. Draw the structures of the substrates and products of the steps that convert the ketone group of the b-ketobutyryl group to a methylene carbon. When a cofactor/cosubstrate is involved, identify it. || CH3-C-CH2-c- HŞ KS MT АT АСР KR ER HD B-Ketobutyryl-ACP
5. There is reciprocal regulation of glycolytic and gluconeogenic reactions interconverting fructose-6-phosphate and fructose-1,6-bisphosphate. Which one of the following statements about this regulation is not correct? FGP A) Fructose-2,6-bisphosphate Fructose-2,6-bisphosphate activates phosphofructokinase-1. Gen inhibits fructose-1,6-bisphosphatase. reaction is exergonic. ATP F16BP BOLALA The fructose-1,6-bisphosphatase D) The phosphofructokinase-1 reaction is endergonic. This regulation allows control of the direction of net metabolite flow through the pathway.