Anaerobic Cellular Respiration  Anaerobic = without oxygen

Anaerobic Cellular Respiration  During Glycolysis, energy is obtained without oxygen.  This type of energy production is called Fermentation.  Fermentation occurs without oxygen.

Fermentation  Bacteria species engage in a host of specific fermentation processes.  Eukaryotic organisms engage in 2 types of fermentation.  Eukaryotes: have a nucleus  This section will focus on these 2 types of fermentation.

Eukaryotic Fermentation  Both methods of fermentation have 2 steps.  Step 1: Glycolysis  Step 2: fermentation (accomplished by recycling the products of glycolysis).

Alcohol Fermentation  Common in yeast.  Acetaldehyde is produced when carbon dioxide was removed from pyruvate by the enzyme pyruvate decarboxylase.  NADH passes Hydrogen Atoms to acetaldehyde.  This generates carbon dioxide, ethanol, and NAD+.  The NADH was a product of glycolysis.

Alcohol Fermentation  The alcohol ethanol is produced as a result.  (alcohol found in alcoholic drinks.)  The process recycles NAD+, therefore, glycolysis can continue.  2 ATP produced in glycolysis satisfy energy needs.  Ethanol and Carbon dioxide are released as wastes.

Alcohol Fermentation

Applications of Alcohol Fermentation  Fermentation is commonly used by humans.  Breads, pastries, wine, beer, liquor, and soy sauce are all produced by fermentation.

Bread  Yeast is added which will undergo fermentation.  The bread will rise due to the release of Carbon dioxide.  Alcohol is also produced  Can you get drunk by eating bread?  Alcohol is produced, but it evaporates upon baking.  Don’t try to eat dough to get drunk!! It will make you sick not drunk.

Wine  Yeast ferments sugar of fruit juice (Grape juice).  Mixture bubbles due to carbon dioxide.  At 12% alcohol concentration yeast cells die.

Homemade Root beer  Is Homemade Root beer Alcoholic?  Fermentation generates alcohol as a waste products, So the answer is Yes.  Homemade Root Beer is about 0.5% alcohol.  A Beer is about 6% alcohol.  You won’t be able to drink the necessary volume of liquid to get drunk.

Homemade Root beer

Lactic Acid Fermentation  During strenuous exercise, the muscles energy demands are greater than aerobic respiration can supply.  Additional ATP is supplied by lactic acid fermentation  See Figure 5 page 224.

Lactic Acid Fermentation  NADH made in glycolysis transfers H atoms to pyruvate to make lactic acid and NAD+  Formation of NAD+ allows glycolysis to continue.  Accumulation of lactic acid leads to muscle stiffness/ soreness, and fatigue.  Lactic acid is transported to the liver and converted to pyruvate when vigorous exercise ceases.

Lactic Acid Fermentation  Pyruvates then go through aerobic respiration  Extra oxygen in necessary to process lactic acid. (oxygen debt)  Panting accompanying hard exercise is the bodies way to pay off the oxygen debt.

Exercise Physiology  The branch of biology that studies the bodies biological responses to exercise.  Most common problem encountered by athletes?  Shortage of energy.

Aerobic Fitness  A measure of the capacity of the heart, lungs, and bloodstream to provide oxygen to the cells of the body during exercise.  Aerobic fitness is one of the major factors to consider when assessing an individuals overall fitness level.

Other Factors  Muscle Strength  Muscular Endurance  Flexibility  Body composition

VO2 Max  Maximum volume of oxygen that the cells can remove from the bloodstream in 1 min/kg of body mass at maximum exertion.  mL/kg/min

Assessing VO2 max  Treadmill test  Person forced to go faster and faster while expired air is collected and measured by a computer.  Lasts about 10 to 15 minutes.

VO2 Max  High VO2 max = better aerobic fitness.  Figure 8 page 225.

2 Components to VO2 Max  Exercise and Genetics.  When an individual increases there levels of exercise, their VO2 max will generally increase as well.  Genetic composition plays a part as well.  This is why some people are elite marathon runners and some are not.  VO2 max also decreases with age.

Lactic Acid Threshold  Value of exercise intensity at which lactic acid production increases  Leads to sore muscles, increased pain, and fatigue.  Exercising below lactic acid threshold = longer duration of exercise  PACE YOURSELF!!!!

Lactic Acid Threshold  Untrained person has a lactic acid threshold at about 60% of VO2 max  Trained person has a lactic acid threshold at about 80% of VO2 max.

Environmental Factors and Cellular Respiration  Environmental Factors can have an influence on cellular respiration.  Two examples are Supplements and Toxins

Supplements  Buffers: counteract the acidic nature of lactic acid and will allow an athlete to have enhanced performance for a short period of time.  Creatine: contains a phosphate that is donated to ADP to allow for the creation of more ATP.  Net effect: more energy available for the muscles to use.  Long term side effects not well understood at this point.

Toxins  Some environmental substances will influence cellular respiration either indirectly or directly.

Indirect Influence  Carbon monoxide binds at the oxygen receptor sites of the bodies hemoglobin.  Oxygen is not available to drive the ETC.  Cell Death follows.

Direct Influence  Cyanide and hydrogen sulfide act directly on a specific rxn within the respiration pathway.

Summary