1. CHAPTER 24: Carbohydrate, Lipid, & Protein Metabolism
General, Organic, & Biological Chemistry
Janice Gorzynski Smith

2. CHAPTER 24: Carbohydrate, Lipid, & Protein Metabolism
Learning Objectives:
Role in Metabolism of fatty acid oxidation, glycolysis, & Amino acid catabolism
Reactions catalyzed by: kinase, isomerase, dehydrogenase, decarboxylase, carboxylase
Glycolysis: steps & net reaction
Pyruvate conversion to acetyl Coenzyme A
Gluconeogenesis: steps in synthesis of glucose
Catabolism of Triacylglycerols: beta-oxidation
Synthesis of ketone bodies: ketogenesis
Catabolism of Amino acids:
transamination & oxidative deamination
Ketogenic vs glucogenic amino acid catabolism
CH 24 Homework:
End of Chapter problems: 30, 36, 38, 42, 47, 52, 58, 60, 64, 68, 71, 75, 76, 78, 80, 82, 96, 98
Smith, Janice Gorzynski. General, Organic, & Biological Chemistry 2nd Ed.

3.  All lead to the production of Acetyl CoA
Metabolism
Step 2 of Metabolism
Fatty acid oxidation
Glycolysis
Amino Acid Catabolism
 All lead to the production of Acetyl CoA
Smith, Janice Gorzynski. General, Organic, & Biological Chemistry 2nd Ed.

4. Metabolism
Step 2 of Metabolism
In the catabolism of carbohydrates, glycolysis
converts glucose into pyruvate, which is then
metabolized into acetyl CoA.

5. Metabolism
Step 2 of Metabolism
In the catabolism of lipids, fatty acids are converted
into thioesters and then cleaved into many
acetyl CoA units.

6. Metabolism
Step 2 of Metabolism
Amino acids are usually reassembled into new
proteins.
Since excess amino acids are not stored in the
body, they can also be catabolized for energy.
The amino groups (NH2) are converted to urea
[(NH2)2C=O], which is excreted in urine.

7. Step 2 of Metabolism: Urea Cycle
Catabolism_of_amino_acids.htm

8. Biochemical Rxns Common Enzymes
Smith, Janice Gorzynski. General, Organic, & Biological Chemistry 2nd Ed.

9. Common Enzymes: Example
Biochemical Rxns
Common Enzymes: Example
The transfer of a phosphate unit from ATP to the
fructose 6-phosphate molecule is catalyzed by
a kinase enzyme.
Smith, Janice Gorzynski. General, Organic, & Biological Chemistry 2nd Ed.

10. Glycolysis Definition
Glycolysis is a linear, 10-step anaerobic pathway that converts glucose into two molecules of pyruvate.
Steps [1] – [5] comprise the energy investment phase, where 2 ATP molecules are hydrolyzed.
The 6-carbon glucose molecule is converted into two 3-carbon segments.
Steps [6] – [10] comprise the energy-generating phase, producing 1 NADH and 2 ATPs for each pyruvate formed.
Smith, Janice Gorzynski. General, Organic, & Biological Chemistry 2nd Ed.

11. Glycolysis Energy Investment
Smith, Janice Gorzynski. General, Organic, & Biological Chemistry 2nd Ed.

12. Glycolysis Energy Generation
Smith, Janice Gorzynski. General, Organic, & Biological Chemistry 2nd Ed.

13. Glycolysis
Step 1
Step [1] begins with the phosphorylation of glucose into glucose 6-phosphate, using an ATP and a kinase enzyme.
Smith, Janice Gorzynski. General, Organic, & Biological Chemistry 2nd Ed.

14. with an isomerase enzyme.
Glycolysis
Step 2
Step [2] isomerizes
glucose 6-phosphate to
fructose 6-phosphate
with an isomerase enzyme.
Smith, Janice Gorzynski. General, Organic, & Biological Chemistry 2nd Ed.

15. fructose 6-phosphate into fructose 1,6-bisphosphate
Glycolysis
Step 3
Step [3] is the
phosphorylation of
fructose 6-phosphate into
fructose 1,6-bisphosphate
with a kinase enzyme.
Steps [1-3] add 2 phosphate groups and isomerize a 6-membered ring into a 5-membered ring. Energy is stored as 2 ATP molecules.
Smith, Janice Gorzynski. General, Organic, & Biological Chemistry 2nd Ed.

16. Step [4] cleaves the fructose ring into a dihydroxy-
Glycolysis
Step 4
Step [4] cleaves the fructose ring into a dihydroxy-
acetone phosphate and a glyceraldehyde 3-phosphate.
Smith, Janice Gorzynski. General, Organic, & Biological Chemistry 2nd Ed.

17. Step [5] isomerizes the dihydroxyacetone phosphate
Glycolysis
Step 5
Step [5] isomerizes the dihydroxyacetone phosphate
into another glyceraldehyde 3-phosphate.
Thus, the first phase of glycolysis converts
glucose into 2 glyceraldehyde 3-phosphate units.
Smith, Janice Gorzynski. General, Organic, & Biological Chemistry 2nd Ed.

18. In step [6] the aldehyde end of the molecule
Glycolysis
Step 6
In step [6] the aldehyde end of the molecule
is oxidized and phosphorylated by a dehydrogenase
enzyme and NAD+; this produces 1,3-bisphospho-
glycerate and NADH.
Smith, Janice Gorzynski. General, Organic, & Biological Chemistry 2nd Ed.

19. In step [7], the phosphate group is transferred
Glycolysis
Step 7
In step [7], the phosphate group is transferred
onto an ADP with a kinase enzyme, forming
3-phosphoglycerate and ATP.
Smith, Janice Gorzynski. General, Organic, & Biological Chemistry 2nd Ed.

20. In step [8], the phosphate group is isomerized to
Glycolysis
Step 8
In step [8], the phosphate group is isomerized to
a new position in 2-phosphoglycerate.
Smith, Janice Gorzynski. General, Organic, & Biological Chemistry 2nd Ed.

21. In step [9], water is lost to form phosphoenol- pyruvate.
Glycolysis
Step 9
In step [9], water is lost to form phosphoenol-
pyruvate.
Smith, Janice Gorzynski. General, Organic, & Biological Chemistry 2nd Ed.

22. In step [10], the phosphate is transferred to an ADP,
Glycolysis
Step 10
In step [10], the phosphate is transferred to an ADP,
yielding pyruvate and ATP with a kinase enzyme.
The 2 glyceraldehyde 3-phosphate units are converted into 2 pyruvate units in Phase two of glycolysis.
Overall, the energy-generating phase forms 2 NADHs and 4 ATPs.
Smith, Janice Gorzynski. General, Organic, & Biological Chemistry 2nd Ed.

23. Glycolysis Overall Reaction
2 ATPs are used in phase one of glycolysis, and 4 ATPs are made in phase two of glycolysis.
The net result is the synthesis of 2 ATPs from glycolysis
The 2 NADHs formed are made in the cytoplasm and must be transported to the mitochondria to join the electron transport chain and make ATP.
Smith, Janice Gorzynski. General, Organic, & Biological Chemistry 2nd Ed.

24. Glycolysis
Pyruvate
Pyruvate can be converted into three possible products depending on the conditions and the organism.
under aerobic
conditions
under anaerobic
conditions
in fermentation
by microorganisms
Smith, Janice Gorzynski. General, Organic, & Biological Chemistry 2nd Ed.

25. Glycolysis
ATP Yield
Smith, Janice Gorzynski. General, Organic, & Biological Chemistry 2nd Ed.

26. Glycolysis ATP Yield 2 x 2.5 ATP = 5 ATP 2 x 2.5 ATP = 5 ATP 2 ATP
Smith, Janice Gorzynski. General, Organic, & Biological Chemistry 2nd Ed.

27. Gluconeogenesis is the synthesis of glucose from
Definition
Gluconeogenesis is the synthesis of glucose from
noncarbohydrate sources—lactate, amino acids,
or glycerol.
Gluconeogenesis is an anabolic pathway since
it results in the synthesis of larger molecules from
smaller ones.
Smith, Janice Gorzynski. General, Organic, & Biological Chemistry 2nd Ed.

28. Cori Cycle Gluconeogenesis
Smith, Janice Gorzynski. General, Organic, & Biological Chemistry 2nd Ed.