1. Nutrition and Metabolism
Dietary Sources of Major Nutrients
Basics of Cellular Respiration
Metabolism of Carbos, Fats, and Protein
Central Role of the Liver in Digestion/Metabolism
Cholesterol and Lipid Transport
Absorptive and Postabsorptive States
Developmental Aspects of Metabolism

2. Sources of Nutrients in the Diet
Macronutrients: Carbohydrates, Protein, Lipids, H2O
Micronutrients: Vitamins, Minerals
Major source of vitamins & minerals
Major source of carbohydrates & B vitamins
Major protein source
some vitamins
Major source of minerals and
vitamins A and D, some protein
Major source of lipids and
fat soluble vitamins A,D,E, K

3. potatoes, pasta, sweets: use sparingly
Red meat, butter:
use sparingly
White rice, white bread,
potatoes, pasta, sweets:
use sparingly
Dairy or calcium
supplement: 1–2 servings
Fish, poultry, eggs:
0–2 servings
Nuts, legumes:
1–3 servings
Vegetables in
abundance
Fruits:
2–3 servings
Whole-grain
foods at
most meals
Plant oils
at most
meals
Daily excercise and weight control
(b) Healthy eating pyramid
Figure 24.1b

4. Nutrition and Metabolism
Dietary Sources of Major Nutrients
Basics of Cellular Respiration
Metabolism of Carbos, Fats, and Protein
Central Role of the Liver in Digestion/Metabolism
Cholesterol and Lipid Transport
Absorptive and Postabsorptive States
Developmental Aspects of Metabolism

5. Oxidation-Reduction is Important in Energy Production
In biological systems, the electrons are often associated with hydrogen atoms. Biological oxidations are often dehydrogenations.
Or FAD FADH2
Sugars, amino acids, fatty acids
Figure 5.10 5

6. The Energy Stored in ATP Can Be Used to Perform Work in the Cell
The energy released by ATP breaking down into ADP and P can power a variety of needs in the cell
ADP
Energized ATP: P
ADP
Discharged ATP: P
Powering the synthesis of molecule Z by coupling oxidation to reduction:
X Y + Z 6

7. Metabolic Pathways Involved in Cellular Respiration
An oxidation of glucose to reduce ADP to ATP 34
Overall Equation for Cellular Respiration

8. Aerobic Cellular Respiration
C6H12O6 + O CO H2O ATP
sugar oxygen carbon dioxide water usable energy
CO2
glucose
CO2
NAD
NADH
Glycolysis
2 ATP
(substrate-level phosphorylation)
Cell membrane
2 pyruvates
CO2
4 ATP
(substrate-level phosphorylation)
Linking Step
mitochondrion
Acetyl CoA
Krebs
Cycle
Electron
Transport
Chain and
ATP Synthase O2
ATP fuels construction/synthesis reactions inside the cell
H 2O
30 ATP
(oxidative phosphorylation)
ATP Synthase

9. Nutrition and Metabolism
Dietary Sources of Major Nutrients
Basics of Cellular Respiration
Metabolism of the Three Macronutrients: Carbohydrates, Fats, and Protein
Central Role of the Liver in Digestion/Metabolism
Cholesterol and Lipid Transport
Absorptive and Postabsorptive States
Developmental Aspects of Metabolism

10. Fat Metabolism Fat metabolism handled mostly by the liver
Some fats used to make ATP
Used to synthesize lipoproteins, thromboplastin, and cholesterol
Release breakdown products to the blood
in liver
Body cells remove fat and cholesterol to build membranes, steroid hormones, adipose cells, and myelin sheaths
acetone and
acetoacetic acid =
ketosis/acid-osis
Oxidation of Fats (ß-Oxidation) for ATP
Fat catabolism yields 9 kcal per gram (vs 4 kcal per gram of carbohydrate or protein)
Fats must first be broken down to acetic acid, then in mito. to H2O, CO2, and ATP
Ketones (acetoacetic acid and acetone can accumulate, producing acidosis/ketosis)

11. Protein Metabolism
urea
deamination

12. Three Macronutrients Used for ATP Production
Stage 1 Digestion in
GI tract lumen to
absorbable forms.
Transport via blood to
tissue cells.
PROTEINS
CARBOHYDRATES
FATS
Amino acids
Glucose and other sugars
Glycerol
Fatty acids
Stage 2 Anabolism
(incorporation into
molecules) and
catabolism of nutrients
to form intermediates
within tissue cells.
Proteins
Glucose
Glycogen
Fats
NH3
Pyruvic acid
Acetyl CoA
Stage 3 Oxidative breakdown
of products of stage 2 in
mitochondria of tissue cells.
CO2 is liberated, and H atoms
removed are ultimately delivered
to molecular oxygen, forming
water. Some energy released is
used to form ATP.
Krebs
cycle
Infrequent
CO2 O2
Oxidative
phosphorylation
(in electron
transport chain) H
H2O
Catabolic reactions
Anabolic reactions
Figure 24.3

13. Nutrition and Metabolism
Dietary Sources of Major Nutrients
Basics of Cellular Respiration
Metabolism of Carbos, Fats, and Protein
Central Role of the Liver in Digestion/Metabolism
Cholesterol and Lipid Transport
Absorptive and Postabsorptive States
Developmental Aspects of Metabolism

14. Role of the Liver in Metabolism
Produces blood proteins (albumin, clotting proteins) and lipoproteins Degrades hormones

15. Liver Modifications on Glucose Levels
Glycogenesis (making glycogen)
Glucose molecules are converted to glycogen
Glycogen molecules are stored in the liver
Glycogenolysis (breaking glycogen)
Glucose is released from the liver after conversion from glycogen
Gluconeogenesis (rebuilding glucose)
Glucose is produced from amino acids and glycerol
Protects against damaging effects of hypoglycemia

16. Roles of Cholesterol in the Body
Keeping membranes fluid
Vitamin D synthesis
Steroid Hormone Synthesis

17. Cholesterol Transport
Cholesterol and fatty acids cannot freely circulate in the bloodstream
They are transported by chylomicron lipoproteins (lipid-protein complexes)
Low-density lipoproteins (LDLs) transport cholesterol to body cells; are increased by dietary saturated and trans-fat
Triglycerides broken down by fat and muscle tissue (lipoprotein lipase) into fatty acids and glycerol
High-density lipoproteins (HDLs) transport from body cells to the liver for breakdown; are increased by exercise, and limited coffee, smoking, and saturated fats/trans fats
Healthy Ratios in the Blood
Total Cholesterol/HDL < 5
LDL/HDL < 2.5
Total cholesterol (mg/dL) Under 200    -   desirable         -   borderline high Over 240      -   high
LDL cholesterol (mg/dL) Below 100    -   optimal         -   near optimal         -   borderline high         -   high Above 190    -   very high
HDL cholesterol (mg/dL) Below 40      -    low 60 or above   -    high 

18. Nutrition and Metabolism
Dietary Sources of Major Nutrients
Basics of Cellular Respiration
Metabolism of Carbos, Fats, and Protein
Central Role of the Liver in Digestion/Metabolism
Cholesterol and Lipid Transport
Absorptive and Postabsorptive States
Developmental Aspects of Metabolism

19. Absorptive and Postabsorptive States
Absorptive (fed) state
During and shortly after eating; absorption of nutrients
Muscle and fat tissue: lipoprotein lipase hydrolyzes lipids of chylomicrons in muscle and fat tissues; most glycerol and fatty acids are converted to triglycerides for storage
Liver: Excess amino acids are deaminated and used for ATP synthesis or stored as fat in the liver
Insulin facilitates glucose uptake, glycogenesis, triglyceride genesis, and protein synthesis
Postabsorptive (fasting) state
When the GI tract is empty; energy sources are supplied by breakdown of reserves
Liver: lipolysis, glycerol then fuels glycogenolysis
Skeletal muscle: glycogenolysis; protein catabolism if starving
Fat tissue: lipolysis tissues and the liver
Glucagon facilitates glycogenolysis and gluconeogenesis in the liver, fat tissue lipolysis

20. Developmental Aspects of the Digestive System
Fetal Development
The alimentary canal is a continuous tube by the fifth week of development
Digestive glands bud from the mucosa of the alimentary tube
The developing fetus receives all nutrients through the placenta
Birth and Infancy
In newborns, feeding must be frequent, peristalsis is inefficient, and vomiting is common
Congenital conditions include cleft palate, phenylketonuria, tracheoesophageal fistula
Teething (eruption of teeth) begins around age six months
Metabolism decreases with old age
Middle age digestive problems
Ulcers
Gall bladder problems
Old Age
Fewer digestive juices
Peristalsis slows
Diverticulosis and cancer are more common
brain damage and retardation in infancy
PKU
Tracheoesophageal Fistula

21. Nutrition and Metabolism
Dietary Sources of Major Nutrients
Basics of Cellular Respiration
Metabolism of Carbos, Fats, and Protein
Central Role of the Liver in Digestion/Metabolism
Cholesterol and Lipid Transport
Absorptive and Postabsorptive States
Developmental Aspects of Metabolism