metabolic pathways and energy production - … 18 metabolic pathways ... chapter 18 metabolic...
TRANSCRIPT
![Page 1: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/1.jpg)
1
18.1 Metabolism and ATP Energy
Chapter 18 Metabolic Pathways and Energy Production
![Page 2: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/2.jpg)
2
Metabolism involves • catabolic reactions
that break down large, complex molecules to provide energy and smaller molecules.
• anabolic reactions that use ATP energy to build larger molecules.
Metabolism
![Page 3: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/3.jpg)
3
Stages of Metabolism
Catabolic reactions are organized as • Stage 1: Digestion and hydrolysis break down
large molecules to smaller ones that enter the bloodstream.
• Stage 2: Degradation break down molecules to two- and three-carbon compounds. • Stage 3: Oxidation of small molecules in the citric
acid cycle and electron transport provides ATP energy.
![Page 4: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/4.jpg)
4
Stages of Metabolism
![Page 5: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/5.jpg)
5
Cell Structure and Metabolism
Metabolic reactions occur in specific sites within cells.
Copyright © 2009 by Pearson Education, Inc.
![Page 6: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/6.jpg)
6
Cell Components and Function
![Page 7: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/7.jpg)
7
ATP and Energy
In the body, energy is stored as adenosine triphosphate (ATP).
![Page 8: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/8.jpg)
8
Hydrolysis of ATP
• The hydrolysis of ATP to ADP releases 7.3 kcal. ATP ADP + Pi + 7.3 kcal
![Page 9: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/9.jpg)
9
ATP and Muscle Contraction
Muscle fibers • contain the protein fibers actin and myosin.
• contract (slide closer together) when a nerve impulse increases Ca2+.
• obtain the energy for contraction from the hydrolysis of ATP.
• return to the relaxed position as Ca2+ and ATP decrease.
![Page 10: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/10.jpg)
10
ATP and Muscle Contraction
Copyright © 2009 by Pearson Education, Inc.
![Page 11: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/11.jpg)
11
Learning Check
Match the following: 1) ATP 2) ADP + Pi A. used in anabolic reactions B. the energy-storage molecule C. coupled with energy-requiring reactions D. hydrolysis products
![Page 12: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/12.jpg)
12
Solution
Match the following: 1) ATP 2) ADP + Pi A. 1 used in anabolic reactions B. 1 the energy-storage molecule C. 1 coupled with energy-requiring reactions D. 2 hydrolysis products
![Page 13: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/13.jpg)
13
18.2 Digestion of foods
Chapter 18 Metabolic Pathways and Energy Production
Copyright © 2009 by Pearson Education, Inc.
![Page 14: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/14.jpg)
14
In Stage 1, the carbohydrates • begin digestion in the mouth, where salivary amylase
breaks down polysaccharides to smaller polysaccharides (dextrins), maltose, and some glucose.
• continue digestion in the small intestine, where pancreatic amylase hydrolyzes dextrins to maltose and glucose.
• maltose, lactose, and sucrose are hydrolyzed to monosaccharides, mostly glucose, which enter the bloodstream for transport to the cells.
Stage 1: Digestion of Carbohydrates
![Page 15: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/15.jpg)
Carbohydrate Digestion
15
![Page 16: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/16.jpg)
16
Digestion of Fats
In Stage 1, the digestion of fats (triacylglycerols)
• begins in the small intestine, where bile salts break fat globules into smaller particles called micelles.
• uses pancreatic lipases to hydrolyze ester bonds, forming glycerol and fatty acids.
• ends as fatty acids bind with proteins for transport to the cells of the heart, muscle, and adipose tissues.
![Page 17: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/17.jpg)
17
Digestion of Triacylglycerols
![Page 18: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/18.jpg)
18
Digestion of Proteins
In Stage 1, the digestion of proteins
• begins in the stomach, where HCl in stomach acid activates pepsin to hydrolyze peptide bonds.
• continues in the small intestine, where trypsin and chymotrypsin hydrolyze peptides to amino acids.
• ends as amino acids enter the bloodstream for transport to cells.
![Page 19: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/19.jpg)
19
Digestion of Proteins
![Page 20: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/20.jpg)
20
Learning Check
Match the end products of digestion with the types of food. 1) amino acids 2) fatty acids and glycerol 3) glucose A. fats B. proteins C. carbohydrates
![Page 21: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/21.jpg)
21
Solution
Match the end products of digestion with the types of food. A. fats 2) fatty acids and glycerol B. proteins 1) amino acids C. carbohydrates 3) glucose
![Page 22: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/22.jpg)
22
Chapter 18 Metabolic Pathways and Energy Production
18.3 Important Coenzymes in
Metabolic Pathways
![Page 23: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/23.jpg)
23
Oxidation and Reduction
To extract energy from foods • oxidation reactions involve a loss of 2 H (2H+ and 2 e–). compound oxidized compound + 2 H • reduction reactions require coenzymes that pick up 2 H. coenzyme + 2H reduced coenzyme
![Page 24: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/24.jpg)
24
Coenzyme NAD+
NAD+ (nicotinamide adenine dinucleotide) • participates in reactions that produce a carbon-oxygen double
bond (C=O). • is reduced when an oxidation provides 2H+ and 2 e–. Oxidation O || CH3—CH2—OH CH3—C—H + 2H+ + 2 e– Reduction NAD+ + 2H+ + 2 e– NADH + H+
![Page 25: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/25.jpg)
25
Structure of Coenzyme NAD+
• contains ADP, ribose, and nicotinamide.
• is reduced to NADH when NAD+ accepts 2H+ and 2 e–.
NAD+ (nicotinamide adenine dinucleotide)
![Page 26: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/26.jpg)
26
Coenzyme FAD
FAD (flavin adenine dinucleotide) • participates in reactions that produce a carbon-carbon
double bond (C=C). • is reduced to FADH2. Oxidation —CH2—CH2— —CH=CH— + 2H+ + 2 e– Reduction FAD + 2H+ + 2 e– FADH2
![Page 27: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/27.jpg)
27
Structure of Coenzyme FAD
FAD (flavin adenine dinucleotide) • contains ADP
and riboflavin (vitamin B2).
• is reduced to FADH2 when flavin accepts 2H+ and 2 e–.
![Page 28: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/28.jpg)
28
Coenzyme A
Coenzyme A (CoA) activates acyl groups such as the two carbon acetyl group for transfer. O O || || CH3—C— + HS—CoA CH3—C—S—CoA Acetyl group Acetyl CoA
![Page 29: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/29.jpg)
29
Structure of Coenzyme A
Coenzyme A (CoA) contains • pantothenic acid (Vitamin B3). • ADP. • aminoethanethiol.
![Page 30: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/30.jpg)
30
Learning Check
Match the following. 1) NAD+ 2) FAD 3) NADH + H+
4) FADH2 5) Coenzyme A A. coenzyme used in oxidation of carbon-oxygen bonds B. reduced form of flavin adenine dinucleotide C. used to transfer acetyl groups D. oxidized form of flavin adenine dinucleotide E. the coenzyme after C=O bond formation
![Page 31: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/31.jpg)
31
Solution
Match the following. 1) NAD+ 2) FAD 3) NADH + H+
4) FADH2 5) Coenzyme A A. 1 coenzyme used in oxidation of carbon-oxygen bonds B. 4 reduced form of flavin adenine dinucleotide C. 5 used to transfer acetyl groups D. 2 oxidized form of flavin adenine dinucleotide E. 3 the coenzyme after C=O bond formation
![Page 32: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/32.jpg)
32
Chapter 18 Metabolic Pathways and Energy Production
18.4 Glycolysis Oxidation
of Glucose
Copyright © 2009 by Pearson Education, Inc.
![Page 33: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/33.jpg)
33
Stage 2: Glycolysis
Stage 2: Glycolysis • is a metabolic
pathway that uses glucose, a digestion product.
• degrades six-carbon glucose molecules to three-carbon pyruvate molecules.
• is an anaerobic (no oxygen) process.
Copyright © 2009 by Pearson Education, Inc.
![Page 34: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/34.jpg)
34
Glycolysis: Energy-Investment
In reactions 1-5 of glycolysis, • energy is required to add phosphate groups to glucose. • glucose is converted to two three-carbon molecules.
Copyright © 2009 by Pearson Education, Inc.
![Page 35: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/35.jpg)
35
Glycolysis: Energy Investment
2
1 3
4
5
Copyright © 2009 by Pearson Education, Inc.
![Page 36: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/36.jpg)
36
Glycolysis: Energy Production
In reactions 6-10 of glycolysis, energy is generated as
• sugar phosphates are cleaved to triose phosphates.
• four ATP molecules are produced.
![Page 37: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/37.jpg)
37
Glycolysis: Reactions 6-10
6
7
8
9
10
Copyright © 2009 by Pearson Education, Inc.
![Page 38: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/38.jpg)
38
In glycolysis, • two ATP add phosphate to glucose and fructose-6-
phosphate.
• four ATP form as phosphate groups add to ADP.
• there is a net gain of 2 ATP and 2 NADH. C6H12O6 + 2ADP + 2Pi + 2NAD+ Glucose 2 C3H3O3
– + 2ATP + 2NADH + 4H+ Pyruvate
Glycolysis: Overall Reaction
![Page 39: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/39.jpg)
39
Learning Check
In glycolysis, what compounds provide phosphate groups for the production of ATP?
![Page 40: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/40.jpg)
40
Solution
In glycolysis, what compounds provide phosphate groups for the production of ATP?
In reaction 7, phosphate groups from two 1,3-
bisphosphoglycerate molecules are transferred to ADP to form two ATP.
In reaction 10, phosphate groups from two phosphoenolpyruvate molecules are used to form two more ATP.
![Page 41: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/41.jpg)
41
Under aerobic conditions (oxygen present), • three-carbon pyruvate is decarboxylated. • two-carbon acetyl CoA and CO2 are produced. O O Pyruvate || || dehydrogenase CH3—C—C—O– + HS—CoA + NAD+ Pyruvate O || CH3—C—S—CoA + CO2 + NADH Acetyl CoA
Pyruvate: Aerobic Conditions
![Page 42: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/42.jpg)
42
Under anaerobic conditions (without oxygen), • pyruvate is reduced to lactate. • NADH oxidizes to NAD+, allowing glycolysis to
continue. O O Lactate || || dehydrogenase CH3—C—C—O–+ NADH + H+
Pyruvate
OH O | || CH3—CH—C—O– + NAD+ Lactate
Pyruvate: Anaerobic Conditions
![Page 43: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/43.jpg)
43
During strenuous exercise, • anaerobic conditions are produced in muscles. • oxygen is depleted. • lactate accumulates. OH │ C6H12O6 + 1ADP + 2Pi 2CH3–CH –COO– + 2ATP Glucose Lactate • muscles tire and become painful. After exercise, a person breathes heavily to repay the oxygen debt and reform pyruvate in the liver.
Lactate in Muscles
![Page 44: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/44.jpg)
44
Pathways for Pyruvate
![Page 45: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/45.jpg)
45
Match the following terms with the descriptions. 1) catabolic reactions 2) coenzymes 3) glycolysis 4) lactate A. produced during anaerobic conditions B. reaction series that converts glucose to pyruvate C. metabolic reactions that break down large molecules to
smaller molecules + energy D. substances that remove or add H atoms in oxidation and
reduction reactions
Learning Check
![Page 46: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/46.jpg)
46
Match the following terms with the descriptions. 1) catabolic reactions 2) coenzymes 3) glycolysis 4) lactate A. 4 produced during anaerobic conditions B. 3 reaction series that converts glucose to pyruvate C. 1 metabolic reactions that break down large molecules
to smaller molecules + energy D. 2 substances that remove or add H atoms in oxidation
and reduction reactions
Solution
![Page 47: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/47.jpg)
47
18.5 The Citric Acid Cycle
Chapter 18 Metabolic Pathways and Energy Production
![Page 48: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/48.jpg)
48
In Stage 3, the citric acid cycle • operates under aerobic conditions only.
• oxidizes the two-carbon acetyl group in acetyl CoA to 2CO2.
• produces reduced coenzymes NADH and FADH2, and one ATP directly.
Citric Acid Cycle
![Page 49: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/49.jpg)
49
Citric Acid Cycle Overview
In the citric acid cycle, • acetyl (2-carbon)
bonds to oxaloacetate (4-carbon) to form citrate (6-carbon).
• oxidation and decarboxylation reactions convert citrate to oxaloacetate.
• oxaloacetate bonds with another acetyl to repeat the cycle.
![Page 50: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/50.jpg)
50
Citric Acid Cycle
![Page 51: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/51.jpg)
51
Reaction 1: Formation of Citrate
Oxaloacetate combines with the two-carbon acetyl group to form citrate.
Oxaloacetate Acetyl CoA Citrate
O
C O O –
C H 2
C
C O O –
S C o A
O C C H 3
C O O –
C H 2
C O O –
H O C C H 2
C O O –
![Page 52: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/52.jpg)
52
Reaction 2: Isomerization to Isocitrate
Citrate • isomerizes to isocitrate. • converts the tertiary –OH group in citrate to a
secondary –OH in isocitrate that can be oxidized.
Citrate Isocitrate
C O O –
C H 2
C O O –
H O C C H 2
C O O –
H H O H
C O O –
C
C O O –
C C H 2
C O O –
![Page 53: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/53.jpg)
53
Summary of Reactions 1 and 2
Copyright © 2009 by Pearson Education, Inc.
![Page 54: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/54.jpg)
54
Reaction 3: Oxidative Decarboxylation (1)
Isocitrate undergoes decarboxylation (carbon removed as CO2). • The –OH oxidizes to a ketone releasing H+ and 2 e–. • Coenzyme NAD+ is reduced to NADH.
α-Ketoglutarate Isocitrate
+ N A D H + C O 2 O
H
C O O –
C
H C
C H 2
C O O –
H H O
H
C O O –
C
C O O –
C
C H 2
C O O –
NAD+
![Page 55: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/55.jpg)
55
Reaction 4: Oxidative Decarboxylation (2)
α-Ketoglutarate • undergoes decarboxylation to form succinyl CoA. • produces a 4-carbon compound that bonds to CoA. • provides H+ and 2 e– to form NADH.
α-Ketoglutarate Succinyl CoA
NAD+
C o A
O S C C H 2
C H 2
C O O –
+ N A D H + C O 2
O
C O O –
C C H 2
C H 2
C O O –
CoA-SH
![Page 56: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/56.jpg)
56
Summary Reactions 3 and 4
Copyright © 2009 by Pearson Education, Inc.
![Page 57: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/57.jpg)
57
Reaction 5: Hydrolysis
Succinyl CoA undergoes hydrolysis, adding a phosphate to GDP to form GTP, a high-energy compound.
CoAS
O
COO-
C
CH2
CH2
COO-
COO-
CH2
CH2 CoA+ GDP + Pi + GTP +
Succinyl CoA Succinate
![Page 58: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/58.jpg)
58
Succinate undergoes dehydrogenation • by losing 2 H and forming a double bond. • providing 2 H to reduce FAD to FADH2.
Reaction 6: Dehydrogenation
+ FAD + FADH2
C O O –
C O O –
C H 2
C H 2 H
H
C O O –
C O O –
C
C
F u m a r a t e S u c c i n a t e
![Page 59: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/59.jpg)
59
Summary of Reactions 5 and 6
Copyright © 2009 by Pearson Education, Inc.
![Page 60: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/60.jpg)
60
Reaction 7: Hydration of Fumarate
Fumarate forms malate when water is added to the double bond.
+ H 2 O H H
C O O –
C H H O C
C O O –
m a l a t e f u m a r a t e
H
H
C O O –
C O O –
C
C
Fumarate Malate
![Page 61: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/61.jpg)
61
Reaction 8: Dehydrogenation
Malate undergoes dehydrogenation • to form oxaloacetate with a C=O double bond. • providing 2 H for reduction of NAD+ to NADH + H+.
+ NAD+
C O O –
C O O –
O
C H 2
C N A D H
o x a l o a c e t a t e
+ H +
m a l a t e
H H
C O O –
C
H H O C
C O O –
Malate Oxaloacetate
![Page 62: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/62.jpg)
62
Summary of Reactions 7 and 8
Copyright © 2009 by Pearson Education, Inc.
![Page 63: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/63.jpg)
63
In the citric acid cycle, • oxaloacetate bonds with an acetyl group to form
citrate. • two decarboxylations remove two carbons as 2CO2. • four oxidations provide hydrogen for 3NADH and one
FADH2. • a direct phosphorylation forms GTP.
Summary of the Citric Acid Cycle
![Page 64: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/64.jpg)
64
Acetyl CoA + 3NAD+ + FAD + GDP + Pi + 2H2O 2CO2 + 3NADH + 2H+ + FADH2 + CoA + GTP
Overall Chemical Reaction for the Citric Acid Cycle
![Page 65: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/65.jpg)
65
How many of each are produced in one turn of the citric acid cycle? A ___ CO2
B. ___ NADH C. ___ FADH2 D. ___ GTP
Learning Check
![Page 66: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/66.jpg)
66
How many of each are produced in one turn of the citric acid cycle? A 2 CO2
B. 3 NADH C. 1 FADH2 D. 1 GTP
Solution
![Page 67: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/67.jpg)
67
18.6 Electron Transport
Chapter 18 Metabolic Pathways and Energy Production
Copyright © 2009 by Pearson Education, Inc.
![Page 68: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/68.jpg)
68
Electron Carriers
Electron carriers • accept hydrogen and
electrons from the reduced coenzymes NADH and FADH2.
• are oxidized and reduced to provide energy for the synthesis of ATP.
Copyright © 2009 by Pearson Education, Inc.
![Page 69: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/69.jpg)
69
Electron Transport
Electron transport • uses electron carriers.
• transfers hydrogen ions and electrons from NADH and FADH2 until they combine with oxygen.
• forms H2O.
• produces ATP energy.
![Page 70: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/70.jpg)
70
Electron Carriers
Electron carriers • are oxidized and reduced as hydrogen and/or electrons
are transferred from one carrier to the next. • are FMN, Fe-S, Coenzyme Q, and cytochromes. e l e c t r o n c a r r i e r A H 2 ( r e d u c e d )
e l e c t r o n c a r r i e r B H 2 ( r e d u c e d )
e l e c t r o n c a r r i e r B ( o x i d i z e d )
e l e c t r o n c a r r i e r A ( o x i d i z e d )
![Page 71: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/71.jpg)
71
Iron-Sulfur (Fe-S) Clusters
Fe-S clusters • are groups of proteins containing iron ions and sulfide. • accept electrons to reduce Fe3+ to Fe2+, and lose
electrons to re-oxidize Fe2+ to Fe3+.
![Page 72: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/72.jpg)
72
FMN (Flavin Mononucleotide)
FMN coenzyme • contains flavin,
ribitol, and a phosphate.
• accepts 2H+ + 2 e– to form reduced coenzyme FMNH2.
![Page 73: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/73.jpg)
73
Coenzyme Q (Q or CoQ)
Coenzyme Q (Q or CoQ) is • a mobile electron carrier derived from quinone. • reduced when the keto groups accept 2H+ and 2 e–.
Copyright © 2009 by Pearson Education, Inc.
![Page 74: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/74.jpg)
74
Cytochromes
Cytochromes (cyt) are • proteins containing
heme groups with iron ions.
Fe3+ + 1 e– Fe2+
• abbreviated as: cyt a, cyt a3, cyt b,
cyt c, and cyt c1.
![Page 75: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/75.jpg)
75
Learning Check
Write the abbreviation for each. A. reduced form of coenzyme Q B. oxidized form of flavin mononucleotide C. reduced form of iron in cytochrome c
![Page 76: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/76.jpg)
76
Solution
Write the abbreviation for each. A. reduced form of coenzyme Q CoQH2, or QH2 B. oxidized form of flavin mononucleotide FMN C. reduced form of cytochrome c Cyt c (Fe2+)
![Page 77: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/77.jpg)
77
Learning Check
Indicate whether the electron carrier in each is oxidized or reduced.
A. FMNH2 FMN
B. Cyt b (Fe3+) Cyt b (Fe2+)
C. Q QH2
D. Cyt c (Fe2+) Cyt c (Fe3+)
![Page 78: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/78.jpg)
78
Solution
Indicate whether the electron carrier in each is oxidized or reduced.
A. FMNH2 FMN oxidized
B. Cyt b (Fe3+) Cyt b (Fe2+) reduced
C. Q QH2 reduced
D. Cyt c (Fe2+) Cyt c (Fe3+) oxidized
![Page 79: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/79.jpg)
79
In the electron transport system, the electron carriers are • attached to the inner membrane of the mitochondrion. • organized into four protein complexes. Complex I NADH dehydrogenase Complex II Succinate dehydrogenase Complex III CoQ-Cytochrome c reductase Complex IV Cytochrome c oxidase
Electron Transport System
![Page 80: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/80.jpg)
80
Electron Transport Chain
![Page 81: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/81.jpg)
81
At Complex I, • hydrogen and electrons are transferred from NADH to
FMN. NADH + H+ + FMN NAD+ + FMNH2
• FMNH2 transfers hydrogen to Fe-S clusters and then to
coenzyme Q, reducing Q and regenerating FMN. FMNH2 + Q QH2 + FMN
• QH2, a mobile carrier, transfers hydrogen to Complex III.
Complex I: NADH Dehydrogenase
![Page 82: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/82.jpg)
82
At Complex II, with a lower energy level than Complex I, • FADH2 transfers hydrogen and electrons to coenzyme
Q, reducing Q and regenerating FAD. FADH2 + Q QH2 + FAD
• QH2, a mobile carrier, transfers hydrogen to Complex III.
Complex II: Succinate Dehydrogenase
![Page 83: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/83.jpg)
83
At Complex III, electrons are transferred • from QH2 to two Cyt b, which reduces Cyt b and
regenerates Q. 2Cyt b (Fe3+) + QH2 2Cyt b (Fe2+) + Q + 2H+
• from Cyt b to Fe-S clusters and to Cyt c, the second
mobile carrier. 2Cyt c (Fe3+) + 2Cyt b (Fe2+) 2Cyt c (Fe2+) + 2Cyt b (Fe3+)
Complex III: CoQ-Cytochrome c reductase
![Page 84: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/84.jpg)
84
Complex IV: Cytochrome c Oxidase
• At Complex IV, electrons are transferred from • Cyt c to Cyt a.. 2Cyt a (Fe3+) + 2Cyt c (Fe2+) 2Cyt a (Fe2+) + 2Cyt c (Fe3+)
• Cyt a to Cyt a3, which provides the electrons to
combine H+ and oxygen to form water. 4H+ + O2 + 4 e- (from Cyt a3) 2H2O
![Page 85: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/85.jpg)
Complex IV
85
Copyright © 2009 by Pearson Education, Inc.
![Page 86: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/86.jpg)
86
Learning Check
Match each with their function. 1) FMN 2) Q 3) Cyt c A. accepts H and electrons from NADH + H+ B. a mobile carrier between Complex II and III C. carries electrons from Complex I and II to Complex III D. accepts H and electrons from FADH2
![Page 87: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/87.jpg)
87
Solution
Match each with their function. 1) FMN 2) Q 3) Cyt c A. 1 accepts H and electrons from NADH + H+ B. 3 a mobile carrier between Complex II and III C. 2 carries electrons from Complex I and II to Complex III D. 2 accepts H and electrons from FADH2
![Page 88: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/88.jpg)
88
Classify each as a product of the 1) citric acid cycle or 2) electron transport chain. A. CO2 B. FADH2 C. NAD+ D. NADH E. H2O
Learning Check
![Page 89: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/89.jpg)
89
Classify each as a product of the 1) citric acid cycle or 2) electron transport chain. A. 1 CO2 B. 1 FADH2 C. 2 NAD+ D. 1 NADH E. 2 H2O
Solution
![Page 90: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/90.jpg)
90
Chapter 18 Metabolic Pathways and Energy Production
18.7 Oxidation Phosphorylation and ATP
Copyright © 2009 by Pearson Education, Inc.
![Page 91: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/91.jpg)
91
Chemiosmotic Model
In the chemiosmotic model • protons (H+) from Complexes I, III, and IV move
into the intermembrane space. • a proton gradient is created. • protons return to matrix through ATP synthase, a
protein complex. • the flow of protons provides energy for ATP
synthesis (oxidative phosphorylation). ADP + Pi + Energy ATP
![Page 92: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/92.jpg)
92
ATP Synthase
At ATP synthase, • protons flow back to
the matrix through a channel in the protein complex.
• energy is generated to drive ATP synthesis.
Copyright © 2009 by Pearson Education, Inc.
![Page 93: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/93.jpg)
93
Chemiosmotic Model of Electron Transport
![Page 94: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/94.jpg)
94
In electron transport, sufficient energy is provided from • NADH (Complex I) oxidation for 3 ATPs. NADH + 3 ADP + 3Pi NAD+ + 3 ATP
• FADH2 (Complex II) oxidation for 2 ATPs. FADH2 + 2 ADP + 2Pi FAD + 2 ATP
Electron Transport and ATP
![Page 95: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/95.jpg)
95
ATP from Electron Transport
![Page 96: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/96.jpg)
96
ATP Energy from Glucose
The complete oxidation of glucose yields • 6CO2, • 6H2O, and • 36 ATP.
![Page 97: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/97.jpg)
97
In glycolysis • glucose forms 2 pyruvate, 2 ATP, and 2 NADH. • NADH produced in the cytoplasm cannot enter the
mitochondria. • a shuttle compound (glycerol-3-phosphate) moves
hydrogen and electrons into the mitochondria to FAD, which forms FADH2.
• each FADH2 provides 2 ATP. Glucose 2 pyruvate + 6 ATP
ATP from Glycolysis
![Page 98: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/98.jpg)
98
ATP from Glycolysis
Reaction Pathway ATP for One Glucose ATP from Glycolysis Activation of glucose -2 ATP Oxidation of 2 NADH (as FADH2) 4 ATP Direct ADP phosphorylation (two triose) 4 ATP 6 ATP Summary: C6H12O6 2 pyruvate + 2H2O + 6 ATP glucose
![Page 99: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/99.jpg)
99
ATP from Two Pyruvate
Under aerobic conditions • 2 pyruvate are oxidized to 2 acetyl CoA and 2 NADH. • 2 NADH enter electron transport to provide 6 ATP. Summary: 2 Pyruvate 2 Acetyl CoA + 6 ATP
![Page 100: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/100.jpg)
100
• One turn of the citric acid cycle provides 3 NADH x 3 ATP = 9 ATP 1 FADH2 x 2 ATP = 2 ATP 1 GTP x 1 ATP = 1 ATP Total = 12 ATP Acetyl CoA 2CO2 + 12 ATP • Because each glucose provides two acetyl CoA, two
turns of the citric acid cycle produce 24 ATP. 2 Acetyl CoA 4CO2 + 24 ATP
ATP from Citric Acid Cycle
![Page 101: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/101.jpg)
101
ATP from Citric Acid Cycle
Reaction Pathway ATP for One Glucose ATP from Citric Acid Cycle Oxidation of 2 isocitrate (2 NADH) 6 ATP Oxidation of 2 α-ketoglutarate (2 NADH) 6 ATP 2 direct substrate phosphorylations (2 GTP) 2 ATP Oxidation of 2 succinate (2 FADH2) 4 ATP Oxidation of 2 malate (2 NADH) 6 ATP
Total 24 ATP Summary: 2 Acetyl CoA 4CO2 + 2H2O + 24 ATP
![Page 102: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/102.jpg)
102
One glucose molecule undergoing complete oxidation provides: From glycolysis 6 ATP From 2 Pyruvate 6 ATP From 2 Acetyl CoA 24 ATP Overall ATP Production for One Glucose: C6H12O6 + 6O2 + 36 ADP + 36Pi Glucose 6CO2 + 6H2O + 36 ATP
Total ATP from Glucose
![Page 103: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/103.jpg)
103
Learning Check
Indicate the ATP yield for each under aerobic conditions. A. Complete oxidation of glucose B. FADH2 C. Acetyl CoA in citric acid cycle D. NADH E. Pyruvate decarboxylation
![Page 104: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/104.jpg)
104
Solution
Indicate the ATP yield for each under aerobic conditions. A. Complete oxidation of glucose 36 ATP B. FADH2 2 ATP C. Acetyl CoA in citric acid cycle 12 ATP D. NADH 3 ATP E. Pyruvate decarboxylation 3 ATP
![Page 105: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/105.jpg)
105
Chapter 18 Metabolic Pathways and Energy Production
18.8 Oxidation of Fatty Acids
Copyright © 2009 by Pearson Education, Inc.
![Page 106: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/106.jpg)
106
β-Oxidation of Fatty Acids
In reaction 1, oxidation • removes H atoms from
the α and β carbons. • forms a trans C=C bond. • reduces FAD to FADH2.
β α
Copyright © 2009 by Pearson Education, Inc.
![Page 107: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/107.jpg)
107
β-Oxidation of Fatty Acids
In reaction 2, hydration • adds water across the
trans C=C bond. • forms a hydroxyl group
(—OH) on the β carbon.
β α
Copyright © 2009 by Pearson Education, Inc.
![Page 108: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/108.jpg)
108
β-Oxidation of Fatty Acids
In reaction 3, a second oxidation • oxidizes the hydroxyl
group. • forms a keto group on
the β carbon. • reduces NAD+ to
NADH.
β α
Copyright © 2009 by Pearson Education, Inc.
![Page 109: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/109.jpg)
109
β-Oxidation of Fatty Acids
In reaction 4, fatty acyl CoA is split • between the α and β
carbons. • to form acetyl CoA
and a shortened fatty acyl CoA that repeats Steps 1-4 of β-oxidation.
Copyright © 2009 by Pearson Education, Inc.
![Page 110: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/110.jpg)
110
Learning Check
Match the reactions of β-oxidation with each. 1) oxidation 1 2) hydration 3) oxidation 2 4) fatty acyl CoA cleaved A. Water is added. B. FADH2 forms. C. A two-carbon unit is removed. D. A hydroxyl group is oxidized. E. NADH forms.
![Page 111: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/111.jpg)
111
Solution
Match the reactions of β-oxidation with each: 1) oxidation 1 2) hydration 3) oxidation 2 4) fatty acyl CoA cleaved A. 2 Water is added. B. 1 FADH2 forms. C. 4 A two-carbon unit is removed. D. 3 A hydroxyl group is oxidized. E. 3 NADH forms.
![Page 112: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/112.jpg)
112
Cycles of β-Oxidation
The number of β-oxidation cycles • depends on the length of a fatty acid. • is one less than the number of acetyl CoA groups
formed. Carbons in Acetyl CoA β-Oxidation Cycles Fatty Acid (C/2) (C/2 –1) 12 6 5 14 7 6 16 8 7 18 9 8
![Page 113: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/113.jpg)
113
β-Oxidation of Myristic (C14) Acid
Copyright © 2009 by Pearson Education, Inc.
![Page 114: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/114.jpg)
114
β-Oxidation of Myristic (C14) Acid (continued)
7 Acetyl CoA
6 cycles
Copyright © 2009 by Pearson Education, Inc.
![Page 115: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/115.jpg)
115
Learning Check
A. The number of acetyl CoA groups produced by the complete β-oxidation of palmitic acid (C16) is
1) 16. 2) 8. 3) 7. B. The number of oxidation cycles to completely
oxidize palmitic acid (C16 ) is 1) 16. 2) 8. 3) 7.
![Page 116: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/116.jpg)
116
Solution
A. The number of acetyl CoA groups produced by the complete β-oxidation of palmitic acid (C16 ) is
2) 8. B. The number of oxidation cycles to completely oxidize
palmitic acid (C16) is 3) 7.
![Page 117: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/117.jpg)
117
β-Oxidation and ATP
• Activation of a fatty acid requires 2 ATP • One cycle of oxidation of a fatty acid produces 1 NADH 3 ATP 1 FADH2 2 ATP • Acetyl CoA entering the citric acid cycle produces 1 Acetyl CoA 12 ATP
![Page 118: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/118.jpg)
118
ATP for Lauric Acid C12
ATP production for lauric acid (12 carbons): Activation of lauric acid -2 ATP 6 acetyl CoA 6 acetyl CoA x 12 ATP/acetyl CoA 72 ATP 5 oxidation cycles 5 NADH x 3 ATP/NADH 15 ATP 5 FADH2 x 2 ATP/FADH2 10 ATP Total 95 ATP
![Page 119: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/119.jpg)
119
Learning Check
The total ATP produced from the β-oxidation of stearic acid (C18) is.
1) 108 ATP. 2) 146 ATP. 3) 148 ATP.
![Page 120: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/120.jpg)
120
Solution
The total ATP produced from the β-oxidation of stearic acid (C18) is:
2) 146 ATP Activation -2 ATP 9 Acetyl CoA x 12 ATP 108 ATP 8 NADH x 3 ATP 24 ATP 8 FADH2 x 2 ATP 16 ATP 146 ATP
![Page 121: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/121.jpg)
121
Ketone Bodies
If carbohydrates are not available, • body fat breaks
down to meet energy needs.
• compounds called ketone bodies form.
Ketone bodies
![Page 122: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/122.jpg)
122
Formation of Ketone Bodies
Ketone bodies form • if large amounts of acetyl CoA accumulate. • when two acetyl CoA molecules form acetoacetyl CoA. • when acetoacetyl CoA hydrolyzes to acetoacetate. • when acetoacetate reduces to β-hydroxybutyrate or
loses CO2 to form acetone, both ketone bodies.
![Page 123: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/123.jpg)
123
Ketosis
Ketosis occurs • in diabetes, diets high in
fat, and starvation.
• as ketone bodies accumulate.
• when acidic ketone bodies lower blood pH below 7.4 (acidosis).
Copyright © 2009 by Pearson Education, Inc.
![Page 124: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/124.jpg)
124
Ketone Bodies and Diabetes
In diabetes • insulin does not
function properly. • glucose levels are
insufficient for energy needs.
• fats are broken down to acetyl CoA.
• ketone bodies form.
Copyright © 2009 by Pearson Education, Inc.
![Page 125: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/125.jpg)
125
Chapter 18 Metabolic Pathways and Energy Production
18.9 Degradation of Amino Acids
Copyright © 2009 by Pearson Education, Inc.
![Page 126: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/126.jpg)
126
Proteins in the Body
Proteins provide • amino acids for
protein synthesis. • nitrogen atoms for
nitrogen-containing compounds.
• energy when carbohydrate and lipid resources are not available.
Copyright © 2009 by Pearson Education, Inc.
![Page 127: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/127.jpg)
127
Transamination
In transamination • amino acids are degraded in the liver. • an amino group is transferred from an amino acid to
an α-keto acid, usually α-ketoglutarate. • a new amino acid, usually glutamate, is formed. • a new α-keto acid is formed.
![Page 128: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/128.jpg)
128
A Transamination Reaction
NH3
+ O | || CH3—CH—COO– + –OOC—C—CH2—CH2—COO–
Alanine α-Ketoglutarate
O NH3
+ || | CH3—C—COO– + –OOC—CH—CH2—CH2—COO–
Pyruvate Glutamate (new α-ketoacid) (new amino acid)
Alanine transaminase
![Page 129: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/129.jpg)
129
Synthesis of Amino Acids
In humans, transamination of compounds from glycolysis or the citric acid cycle produces nonessential amino acids.
Copyright © 2009 by Pearson Education, Inc.
![Page 130: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/130.jpg)
130
Oxidative Deamination
Oxidative deamination • removes the amino group as an ammonium ion from
glutamate. • provides α-ketoglutarate for transamination. NH3
+ Glutamate │ dehydrogenase –OOC—CH—CH2—CH2—COO– + NAD+ + H2O Glutamate
O || –OOC—C—CH2—CH2—COO– + NH4
+ + NADH α-Ketoglutarate
![Page 131: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/131.jpg)
131
Learning Check
Write the structures and names of the products for the transamination of α-ketoglutarate by aspartate. NH3
+ | –OOC—CH—CH2—COO– aspartate O || –OOC—C—CH2—CH2—COO–
α-ketoglutarate
![Page 132: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/132.jpg)
132
Solution
Write the structures and names of the products for the transamination of α-ketoglutarate by aspartate. O || –OOC—C—CH2—COO– Oxaloacetate NH3
+ | –OOC—CH—CH2—CH2—COO–
Glutamate
![Page 133: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/133.jpg)
133
Urea Cycle
The urea cycle • removes toxic ammonium ions from amino acid
degradation. • converts ammonium ions to urea in the liver. O + || 2NH4 + CO2 H2N—C—NH2 Ammonium ion Urea • produces 25-30 g of urea daily for urine formation
in the kidneys.
![Page 134: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/134.jpg)
134
Carbon Atoms from Amino Acids
Carbon skeletons of amino acids • form intermediates of the citric acid cycle. • produce energy.
Three-carbon skeletons: alanine, serine, and cysteine pyruvate Four-carbon skeletons: aspartate, asparagine oxaloacetate Five-carbon skeletons: glutamine, glutamate, proline, arginine, histidine glutamate
![Page 135: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/135.jpg)
135
Intermediates of the Citric Acid Cycle from Amino Acids
![Page 136: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/136.jpg)
136
Learning Check
Match each the intermediate with the amino acid that provides its carbon skeleton. 1) pyruvate 2) fumarate 3) α-ketoglutarate A. cysteine B. glutamine C. aspartate D. serine
![Page 137: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/137.jpg)
137
Solution
Match each the intermediate with the amino acid that provides its carbon skeleton. 1) pyruvate 2) fumarate 3) α-ketoglutarate A. 1 cysteine B. 3 glutamine C. 2 aspartate D. 1 serine
![Page 138: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/138.jpg)
138
Overview of Metabolism
In metabolism • catabolic pathways degrade large molecules. • anabolic pathway synthesize molecules. • branch points determine which compounds are
degraded to acetyl CoA to meet energy needs or converted to glycogen for storage.
• excess glucose is converted to body fat. • fatty acids and amino acids are used for energy when
carbohydrates are not available. • some amino acids are produced by transamination.
![Page 139: Metabolic Pathways and Energy Production - … 18 Metabolic Pathways ... Chapter 18 Metabolic Pathways and Energy Production . 18.4 . ... Reaction 4: Oxidative](https://reader031.vdocument.in/reader031/viewer/2022022009/5aee5cdb7f8b9ad0618b6ff4/html5/thumbnails/139.jpg)
139
Overview of Metabolism