1. Anatomy and Physiology
Biology 2402
Chapter-25
Metabolism and Energetics

2. Anabolic and Catabolic Reactions http://web. biosci. utexas

3. Figure 25-2 Nutrient Use in Cellular Metabolism
Structural, functional, and storage components
Triglycerides
Glycogen
Proteins
Organic
compounds that
can be absorbed
by cells are
distributed to
cells throughout
the body by the
bloodstream.
Nutrient
pool
Fatty acids
Glucose
Amino acids
Three-carbon chains
Two-carbon chains
MITOCHONDRIA
Citric
acid
cycle
Electron
transport
system
Coenzymes
KEY
 Catabolic
pathway
 Anabolic
pathway 3

4. http://www. sumanasinc

5. Glycolysis

6. Transition reaction

7. Kreb’s cycle/Citric Acid Cycle
Kreb’s cycle/Citric Acid Cycle

8. Electron transport system chemiosmosis (part 1)

9. Electron transport system chemiosmosis (part 2)

10. Oxygen debt and lactic acid

11.
Fermentation

12. Alcoholic fermentation
Alcoholic fermentation

13. Glycogenesis & Glycogenolysis https://youtu.be/1R6KB12Wtyw
Glycogenesis is the synthesis of glycogen from glucose in the liver and skeletal muscle.
It is regulated by insulin, and occurs when the blood glucose levels are high.
Insulin stimulate liver and mucle cells to absorb glucose and store it as glycogen.
Glycogenolysis is the break down of glycogen to release glucose.
It is regulated by glucagon and epinephrine, and occurs in response to low glucose blood levels.
Liver and muscle cells are stimulated by these two hormones to break down glycogen to release glucose.
Only liver cells are able to release glucose to the blood.

14. Gluconeogenesis
Gluconeogenesis is the generation of glucose from non carbohydrate molecules like pyruvic acid, lactic acid, glycerol, and glucogenic amino acids.
It is stimulated by cortisol and glucagon and occurs primarily in the liver. It can also occur in the kidney.

15. Lipid catabolism

16. Lipolysis and Other Lipids Functions
Adipose triglycerides are broken down and released as free fatty acids.
Free fatty acids are taken up by cells and broken down by beta-oxidation into acetylCoA which can enter the citric acid cycle or can be converted to ketone bodies.
Other lipids are used as structural molecules or to synthesize essential molecules. Examples include
phospholipids of plasma membranes
lipoproteins that transport cholesterol
thromboplastin for blood clotting
myelin sheaths to speed up nerve conduction
cholesterol used to synthesize bile salts and steroid hormones.

17. Health problems
Hypertrophic obesity – severe increase in adipose cell size via massive accumulation of fatty acids within the fat droplet. These mainly occur in White adipose tissue
Hypercellular obesity – result from the over-abundance of adipocytes. This is due to the adipose cells abnormally divided in fetal, neonatal period. Adipose cells do not divide in adults therefore the division took place in youth.

18. Amino Acids Catabolism
Amino acids must be converted to various substances to enter the Krebs cycle for oxidation.
Amino acid conversion occurs in the liver.
Amino acids can be:
Deaminated
Decarboxylated
Dehydrogenated
Deamination removes the amino group and creates nitrogenous wastes such as urea.

19. Essential Amino Acids
Essential amino acids are molecules that we cannot synthesize, or that we synthesize in low amount.
Humans cannot synthesize leucine, isoleucine, lysine,methionine, phenylalanine, threonine, tryptophan, and valine.
Arginine and histidine are not synthesized in sufficient amounts.

20. Metabolic Pathways during the Absorptive State

21. Metabolic Pathways during the Postabsorptive State

22. Fasting and Starvation
Fasting means going without food for many hours or a few days.
Starvation implies weeks or months of food deprivation or inadequate food intake.
Catabolism of stored triglycerides and structural proteins can provide energy for several weeks.
The amount of adipose tissue determines the lifespan possible without food.
During fasting and starvation, nervous tissue and red blood cells continue to use glucose for ATP production.