Energy Systems Nutrition

I. Nutrients: substances needed for growth, metabolism and bodily functions. A. Micronutrients: nutrients required by humans in small amounts to orchestrate a wide variety of physiological functions, but are not made by the organism. Water Fiber Vitamins minerals

B. Macronutrients: nutrients that provide calories or energy and are required in large amounts. *Carbohydrates *Lipids (fats) *Proteins

1. Carbohydrates: serve important functions related to energy metabolism and exercise. *contain C, H and O at a ratio of 1:2:1 (CH 2 O) n *end with “ose” a. Monosaccharides: bodies main energy source. (glucose, fructose, galactose)

b. Disaccharides: the combination of “two” monosaccharides (double sugar). *each disaccharide contains glucose Ex. glucose + fructose =sucrose *formed by dehydration synthesis (condensation reaction) from the removal of water.

c. Polysaccharides: three or more sugars combined. i. Plant polys: *Starch- found in seeds, grains and corn cells (complex carbs.) *Fiber- (cellulose) a non-starch found in plant cell walls.

ii. Animal Polys: glycogen, formed by glucogenesis, is stored in mammalian muscle and liver.

2. Lipids (oils, fats and waxes): consist primarily as triacylglycerols having a glycerol and 3 fatty acid chains. Found in adipose tissue and skeletal muscle. Lipids Role in the Body *Energy Reserve *Thermal insulation *Energy reserve *Transport of fat soluble vitamins *Hunger suppressor

a. Saturated vs. Unsaturated Fatty Acids i. Saturated: contain only single bonds between carbon atoms, all other bonds attach to hydrogen. ii. Unsaturated: contain one or more double bonds along the carbon chain.

3. Proteins: contain carbon, hydrogen, oxygen and nitrogen. Proteins Role in the Body *tissue synthesis (anabolism) *constituents of plasma membranes *globular proteins make up enzymes

a. Amino Acids: the building blocks of proteins joined by peptide bonds. The body requires 20 diff. amino acids. i.Essential Aminos: 8 aminos that are not synthesized in the body and must be ingested. ii.Nonessential Aminos: the remaining 12 aminos manufactured by the body.

II. Recommendations for a Balanced Diet

A. Food Energy Content: is the amount of energy obtained from food through cellular respiration Energy Values Per 100 grams of: Carbs. = 1600 kilojoules (kJ) Lipids = 3700 (kJ) Proteins = 1700 (kJ) *one food calorie equals about (kJ)

Recommended Dietary Intakes Atheletes *Carbs. – g Non-Athletes *Carbs. – 300g *Fats – 65g

III. Carbohydrate and Fat Metabolism A.Metabolism: set of chemical reactions in living organisms to maintain life. 1. Catabolism: breaks down organic matter. 2. Anabolism: uses energy to construct cellular components.

B. The Pancreas: serves as an endocrine and exocrine gland and regulates blood sugar levels and aids in digestion. 1. Islets of Langerhans: clusters of cells within the pancreas. a.Beta cells: make up ¾ of the islet cells and secrete insulin. b.Alpha cells: secrete glucagon.

2. The Role of Insulin: increases glucose uptake by cells. Exercise increases glucose uptake into skeletal muscle. a.Glycogenesis: Insulin activates enzymes for the synthesis of glycogen. b.Lipogenesis: insulin inhibits catabolism of fatty acids to convert excess glucose into triacylglycerols.

3. The Breakdown of Glycogen a. Glycogenolysis: glucagon and adrenaline stimulate the breakdown of glycogen in the liver to increase blood glucose levels during long periods of exercise and times of fasting.

b. Lipolysis: the breakdown (catabolism) of adipose tissue by glucagon and adrenaline to increase blood sugar.

IV. Nutrition and Energy Systems A. Generalized Animal Cell: *ribosomes *rough ER *golgi complex *lysosomes *nucleus *mitochondrion

B. Cellular Respiration: the release of energy from organic compounds in cells. 1.Mitochondria: the site of cellular respiration.

2. Adenosine Triphosphate: (ATP) the energy currency of the cell. *the removal of the outermost phosphate releases energy (7.3 kCal) for cellular activity. ATP ADP

a. Phosphocreatine system: (ATP-CP) re- synthesizes ATP by the hydrolysis of phosphocreatine (PCr). *phosphate is removed from PCr and added to ADP to reform ATP. *this occurs at the onset of intense exercise without oxygen.

3. Stages of Cellular Respiration: C 6 H 12 O 6 + 6O 2 6CO 2 +6H 2 O+36 ATP a.Glycolysis: (anaerobic phase) *takes place in the cytoplasm *glucose is split into two pyruvates *yields 4 ATP with a net gain of 2 ATP

i. Lactic Acid Fermentation: if O 2 is deficient the pyruvates are converted into lactic acid. *ATP production is limited, resulting in muscle fatigue.

b. Aerobic system: in the presence of oxygen pyruvate is processed within the mitochondria. i.Pyruvates combine with 2 coenzyme A molecules to form acetyl-CoA. ii.Krebs Cycle: Occurs in the matrix where acetyl-CoA is broken down to CO 2 and H +. H + combine with electron carriers NAD and FAD.

iii. Electron transport chain: occurs in the cristae and is used to transport electrons from NADH and FADH 2. *H + pumped across the membrane diffuse back in to generate 32 ATP (oxidative phosphorylation). *Oxygen acts as the final H + acceptor to form H 2 O. *occurs at a rate of 10,000,000 ATP per/sec in working muscle cells!

iv. Beta Oxidation: Triacylglycerol is hydrolized to form fatty acids and glycerol that can be used as an energy source for cellular respiration. * glycerol enters glycolysis to form pyruvate. * Fatty acid chains are transformed into acetyl-CoA that enter the Krebs cycle. * O 2 must be present for this to occur.

C. What role does each energy system (ATP-PCr, glycolytic and aerobic) play during exercise? 1.ATP-PCr: supplies the immediate energy for short, explosive movements. Ex. Sprint, swinging a bat. 2.Glycolytic: supplies energy after the initial 10 sec. of exercise. Used in multiple sprint sports (soccer, hockey).

3. Aerobic System: supplies long term energy when exercise extends longer than 2-3 minutes.

D. Oxygen Deficit: diff. between the amt. of O 2 consumed during exercise and the amt. that would have been consumed if aerobic resp. occurred immediately. *this reflects the amt. of energy supplied to muscles by the anaerobic systems. *trained athletes have a smaller O 2 deficit.

E. Oxygen Dept. (EPOC) excess post-exercise oxygen consumption *represents the amt. of O 2 consumed in recovery after exercise that is above the resting level.