All biochemical events occuring in body at all times

1. Anabolism: build up; smaller molecules generate larger ones; ex: amino acids become proteins; prominent in growth/development

2. Catabolism: breakdown larger molecules--> smaller components; ex: glucose broken down to yield energy

3. Cellular (Internal) Respiration: purpose is to generate ATP; collection of catabolic events involved in breakdown of food products

4. Metabolic Flow: process of energy containing nutrients starting with digestion, passing to blood, and then to tissue; remainder broken down into ATP

Food--> ATP synthesis--> Existing Energy Stores

-Oxidation: Gain O2 or lose H atoms/electrons

-Reduction: Lose O2 or gain H atoms/electrons

-Energy Transfer: energy is lost in the oxidized substance and gained by reduced substance

-Redox Enzymes: Dehydrogenases & oxidases

-Redox rxns require Cofactors; two types: NAD+ & FAD+ (derivatives of B vitamins Niacin & Riboflavin); these compounds transfer energy from one to another

Direct phosphorylation; typically formation of ATP; to phosphorylize = activate something; Energy in phosphate bond; ex: X + P + ADP (+ enzyme) --> X + ATP

Mitochondrion: electron transport chain; mult-step process; indirect phosphorylation; requires O2

Quickest sources of energy;

1. Stored ATP: in myosin head (pre-synthesized)

2. Creatine Kinase Reaction: substrate-level phosphorylation- Creatine + Phosphate + ADP --> ATP (& creatine left behind)

3. Glycolysis: glucose breakdown

-Location: Cytoplasm

-Products Invested: 1 molecule of Glucose (only partially broken down/oxidized); 2 ATP

-Products Generated: 2 Pyruvates (untapped energy), Net gain of 2 ATP (immediate energy), and 2 reduced forms of NAD+ (energy being transferred)

1. Sugar Activation: invest 2 ATP to activate (energize) glucose molecule (changes into fructose and phosphorylate)

2. Sugar Cleavage: break 6-carbon molecule into 2, 3-Carbon molecules (each carrying a phosphate)

3. Oxidation & ATP formation: extract energy out of glucose to get Net gain of 2 ATP; each molecule is oxidized (H atoms removed and transferred to NAD); forms 4 ATP from phosphorylation of 4 ADP

In the mitochondria:

1. Conversion of 3C Pyruvate into 2C acetyl CoA (x2)

2. Krebs Cycle: Acetyl CoA broken down completely

3. Electron Transport Chain: extracts energy from reduced compounds & makes ATP

Location: Mitochondrial matrix

Products Invested:

• 2 Acetyl CoA

Products Generated:

• 6 NADH + H+ (reduced cofactor)
• 2 FADH2 (reduced cofactor
• 2 ATP

-Location: Inner Mitochondrial Membrane

-Products Invested: reduced compounds;

-Products Generated: ~ 28 ATP & Water

*Process* removes H atoms from cofactors [NADH +H+] & [FADH2] and splits atom into proton [H+] & electron [e-]; e- passed down chain, energy from e- utilized to pump H+ into intermembrane space; creates concentration gradient of H+ outside of inner membreane and e- inside membrane; ATP synthase within membrane allows H+ ions to pass through along electrochemical gradient to mitochondrial matrix; Synthase harnesses this energy from diffusion to synthesize ATP as H+ diffuses across membrane and e- are picked up by O2 in mitochondria to form water with H+

1. Glycolysis: 2 ATP (anerobic)

2. Krebs: 2 ATP (aerobic)

3. Electron Transport Chain: (aerobic)

-8 NADH + H+ from Krebs--> 24 ATP

-2 FADH2 from Krebs--> ATP

-2 NADH + H+ from Glycolysis--> 4-6 ATP

Total ATP from glucose ~ 32

1. Anaerobic: does not require O2 to move forward; ex: creatine kinase reactions and glycolysis

2. Aerobic: does require O2; O2 is final electron acceptor in ETC

3. Anaerobic Threshold: during heavy exercise, an increase in blood lactate is seen; however, pyruvate is NOT converted to lactic acid instead of entering krebs cycle because of a lack of O2; O2 is present always in a healthy person; the reason for the buildup is because Krebs and ETC have slower velocity than glycolysis; therefore, creates back up of pyruvate which is then shuttled over to lactate to be used as fuel. This is NOT a conversion to anerobic production

Physiological inability to contract skeletal muscle

Causes:

• ATP prodcution fails to keep up pace with usage
• Psychological factors (don't feel like it)
• pH changes (lactic acid is an acid so pH drops, making enzymes less efficient)
• Neurological Transpission of AP, either through nerve or at neuromuscular junction itself
• Ionic imbalances (K+ loss)
• Mitochondrial function (chronic fatigue syndrome)

Panting; repayment of O2 debt; replenishment of oxygen reserves, glycogen stores, and ATP resynthesized

Only 20-25% efficient conversion of ATP bond energy converted to kinetic energy; remainder given off as heat

• Carbohydrates
• Lipids
• Proteins

Fuel Interconversion: Carbs, lipids, and proteins can be used as fuel for ATP production

Glucose;

1. Glycogenesis: make glycogen from glucose

2. Glycogenolysis: break down glycogen to extract glucose

3. Gluconeogenesis: make new glucose from other source (ex: amino acid)

also used for fuel; products of breakdown can be fed into krebs & glycolysis pathways, where energy is extracted

1. Lipogenesis: storage of lipids

2. Lipolysis: break down of lipids to use as energy

Can also be used for fuel (usually in a starvation state)

1. Oxidation of Amino Acids

2. Protein Synthesis: making structures & enzymes to make cell function