F ERMENTATION Sections

F ERMENTATION - ANAEROBIC RESPIRATION There are two types Alcoholic fermentation-carried out by yeast Glucose is used to make 2 Ethanol, 2 CO2 Lactic acid fermentation- carried out by specific bacteria or human muscle cells glucose creates : 2 Lactic acid molecules

F ERMENTATION Both types start with glycolysis Creates 2 ATP, 2NADH, and 2 pyruvate When oxygen is not available the cell can not cash out NADH to make ATP NADH donates electrons to a pyruvate to create a waste product NADH is recycled so that glycolysis can restart Is a fairly inefficient process Is an anaerobic process

L ACTIC A CID FERMENTATION Carried out by muscle cells when we cannot deliver oxygen to them quickly enough (when we exercise strenuously and are not in shape) Lactic acid build up is carried to liver to be broken down Causes fatigue, and muscle soreness Used by bacteria to create yogurt, sauerkraut, and soy sauce

A LCOHOL F ERMENTATION Yeast are used to create alcoholic beverages. Alcohol kills the yeast and CO2 may be removed or retained for carbonation Yeast create CO2 which cause bread to rise. Alcohol evaporates during the baking process

A NAEROBIC BACTERIA Some bacteria are killed by oxygen – strict anaerobes Other organisms like yeast are facultative anaerobes because they can use oxygen if it is available but can also ferment sugar if oxygen is absent. Alcoholic beverages must be made in an environment without O2 or the liquid becomes acidic/like vinegar

H OW ARE FOOD MOLECULES USED I N CELL RESPIRATION ? Polysaccharides and disaccharides are digested in to monosaccharides and used in glycolysis Proteins are generally not used as fuel, but the amino acids are used to make new human protein Proteins can be used as fuel in the citric acid cycle after amino group is removed in urine Lipids are broken into glycerol and 3 fatty acids. Glycerol is used in glycolysis, FA broken into many 2C fragments and used in Kreb’s cycle

B IOSYNTHESIS Not all food is fuel. We use molecules to create new tissue (protein and DNA) and to create molecules not available in the food we eat. We can make most of the 20 amino acids by modifying amino acids in the proteins we eat

C OMPARING PHOTOSYNTHESIS AND RESPIRATION