CELLULAR RESPIRATION

Cellular Respiration Biology 20 Anaerobic Respiration

Anaerobic Respiration „

„

„

„

Glycolysis allows organisms to obtain energy from nutrients in the absence of oxygen. NAD+ is reduced to NADH; NADH is oxidized in the ETC when oxygen is present, which regenerates NAD+ supplies for glycolysis. Without NAD+, glycolysis would come to a halt, as would ATP production. Therefore, there must be a way to regenerate NAD+ without the presence of oxygen. Solution = Fermentation „ „ „

Alcohol Fermentation Lactic Acid Fermentation Ethanol Fermentation

Fermentation Alcohol FermentationÆ „

„ „

NADH’s produced during glycolysis pass their hydrogen atoms to acetaldehyde, a compound formed when a carbon dioxide molecule is removed from pyruvate by the enzyme pyruvate decarboxylase. This results in ethanol, the type of alcohol used in alcoholic beverages. This process recycles NAD+ and allows glycolysis to continue. 2 ATP (glycolysis) „ Ethanol and CO2 released as waste products. „

Alcohol Fermentation Chemical Equation

Glucose + 2ADP + Pi Æ 2 ethanol + 2CO2 + 2ATP

Lactic Acid Fermentation Lactic Acid FermentationÆ „

„ „ „

Occurs during strenuous exercise, muscle cells demand more ATP energy than can be supplied by aerobic respiration alone. NADH transfers its hydrogen to pyruvate; thus, pyruvate becomes lactic acid. Accumulation of lactic acid in muscle tissues causes stiffness, soreness, and fatigue. Once exercises ceases, lactic acid can be converted back to pyruvate and regular aerobic respiration can continue

Lactic Acid Fermentation Chemical Equation Glucose + 2ADP + Pi Æ 2 lactic acid + 2ATP

Exercise Physiology „

Aerobic fitnessÆ a measure of the ability of the heart, lungs, and bloodstream to supply oxygen to the cells of the body during physical exercise.

„

Maximum oxygen consumption (VO2 max)Æ the maximum volume of oxygen, in milliliters, that the cells of the body can remove the bloodstream in one minute per kilogram of body mass while the body experiences maximal exertion. Figure 7, Page 225

„

Lactic Acid ThresholdÆ is a value of exercise intensity at which blood lactic acid concentration begins to increase sharply. Exercise below this level can be maintained for hours. Figure 9, Page 92

„

Maximum oxygen consumption (VO2 max)Æ the maximum volume of oxygen, in milliliters, that the cells of the body can remove the bloodstream in one minute per kilogram of body mass while the body experiences maximal exertion. Figure 7, Page 225

What exactly is your VO2 Max?

„

„

„

„

VO2 Max is defined as the highest rate at which oxygen can be taken in and used during high intensity dynamic exercise. When you are exercising aerobically on your treadmill, each and every muscle contraction requires oxygen to break down the fats, carbohydrates, and protein; thus, providing energy (ATP) needed to fuel the muscles in order for movement to occur. Humans, at rest, need 3.5 ml of oxygen, every minute, for each kilogram of body weight just to support the cellular activities in the tissues that keep us alive. Now let's get back to our treadmill. As you increase the speed or incline (intensity), more oxygen is required to transfer the oxygen through the blood and into the muscles. Due to increased intensity during your exercise session, more oxygen is required to initiate the energy releasing process. Now let's take the treadmill up to a speed and incline where you can no longer catch your breath comfortably. The intensity has increase significantly, but you have reached an upper limit on the amount of oxygen you can take in. This is your VO2 Max.

Creatine Phosphate „ „

Occurs naturally in the body and in foods. Supplements are used to increase the amount of phosphate in the muscles; therefore, more ATP and more energy.

What is your VO2 max? „

VO2 Max values differ from individual to individual. Factors such as age, health, activity levels, training programs, and genetics all affect VO2 Max. A sedentary person has a VO2 Max of around 20 ml of oxygen per kilogram of body weight per minute of exercise. A highly trained endurance athlete can have a VO2 Max of 70 ml/kg/min.

Now why does Lance Armstrong win all those bike races? „

„ „ „ „ „ „ „ „ „ „ „

Yes, he has a great training program, a great coach, and great equipment. However, his genetics for an endurance athlete are nothing short of astounding. Do you know his VO2 Max measures around 83-85 ml/kg/min, while an average person's is around 40? For Lance, his success is attributed to a combination of great training, will, desire, and unbelievable genetic makeup. A Super Human Lance: 1. Lungs - 2 times the capacity of the average person 2. Muscle - Accumulates less lactic acid and is more efficient at removing it. 3. Heart - Is about 1/3 larger with a resting heart rate of 32 beats per minute, and peaks around 200 beats per minute. 4. Body Fat - 4-5 percent before the Tour starts, while an average person has 15-20 percent. 5. Food Consumption - Needs 6500 calories per day, and upwards of 10,000 per day when biking in the mountains during his 120 mile race. Truly amazing!

Carbon Monoxide „

„

Binds to hemoglobin protein in your red blood cells. These proteins are responsible for carrying oxygen throughout your body. Without final electron acceptor, ECT shuts down, to little ATP, and cell death follows shortly afterwards.