TAILIEUCHUNG - Biochemistry, 4th Edition P70

Biochemistry, 4th Edition P70. Continuing Garrett and Grisham's innovative conceptual and organizing framework, "Essential Questions," BIOCHEMISTRY guides students through course concepts in a way that reveals the beauty and usefulness of biochemistry in the everyday world. Streamlined for increased clarity and readability, this edition also includes new photos and illustrations that show the subject matter consistently throughout the text. New end-of-chapter problems, MCAT practice questions, and the unparalleled text/media integration with the power of CengageNOW round out this exceptional package, giving you the tools you need to both master course concepts and develop critical problem-solving skills you can draw upon. | How Is Carbon Dioxide Used to Make Organic Molecules 653 3-phosphoglycerate. In the course of this metabolic sequence the NADPH and ATP produced in the light reactions are consumed as indicated earlier in Equation . The Calvin cycle of reactions starts with ribulose bisphosphate carboxylase catalyzing formation of 3-phosphoglycerate from CO2 and RuBP and concludes with ribulose-5-phosphate kinase also called phosphoribulose kinase which forms RuBP Figure and Table . The carbon balance is given at the right side of Table . Several features of the reactions in this table merit discussion. Note that a total of 18 equivalents of ATP consumed in hexose formation are expended reactions 2 and 15 12 to form 12 equivalents of 1 3-bisphosphoglycerate from 3-phosphoglycerate by a reversal of the normal glycolytic reaction catalyzed by 3-phosphoglycerate kinase and six to phosphorylate Ru-5-P to regenerate 6 RuBP. All 12 NADPH equivalents are used in reaction 3. Plants possess an NADPH-specific glyceraldehyde-3-phosphate dehydrogenase which contrasts with its glycolytic counterpart in its specificity for NADP over NAD and in the direction in which the reaction normally proceeds. The Calvin Cycle Reactions Can Account for Net Hexose Synthesis When carbon rearrangements are balanced to account for net hexose synthesis five of the glyceraldehyde-3-phosphate molecules are converted to dihydroxyacetone phosphate DHAP . Three of these DHAPs then condense with three glyceraldehyde-3-P via the aldolase reaction to yield three hexoses in the form of fructose bisphosphate Figure . Recall that the AGfor the aldolase reaction in the glycolytic direction is kJ mol. Thus the aldolase reaction running in reverse in the Calvin cycle would be thermodynamically favored under standard-state conditions. Taking one FBP to glucose the desired product of this scheme leaves 30 carbons distributed as 2 fructose-6-phosphates 4 glyceraldehyde-3-phosphates and 2 DHAP. .

• Sinh học
• Nền tảng của hóa sinh học
• trao đổi chất protein
• RNA trao đổi chất
• nguyên tắc của hóa sinh
• Axit amin
• công nghệ DNA