Cellular Energy Photosynthesis and Cellular Respiration

Photosynthesis Basic reaction: Basic reaction: 6 CO H 2 O + light energy, chlorophyll, enzymes → C 6 H 12 O O H 2 O 6 CO H 2 O + light energy, chlorophyll, enzymes → C 6 H 12 O O H 2 O Rate varies with Rate varies with Availability of raw materials Availability of raw materials Intensity of sunlight Intensity of sunlight Temperature (best at 20-35°C / °F) Temperature (best at 20-35°C / °F)

Photosynthesis Pigments Pigments Chlorophyll Chlorophyll Chlorophyll a and chlorophyll b most common types. Chlorophyll a and chlorophyll b most common types. Captures light energy and feeds it into photosynthetic process Captures light energy and feeds it into photosynthetic process Xanthophylls Xanthophylls Yellow pigments that capture light energy and transfer it to chlorophyll a. Yellow pigments that capture light energy and transfer it to chlorophyll a. Carotenes Carotenes Orange pigments that capture light energy and transfer it to chlorophyll a. Orange pigments that capture light energy and transfer it to chlorophyll a.

Photosynthesis Light Reactions Light Reactions Light energy transferred from chlorophyll a is used to Light energy transferred from chlorophyll a is used to Convert some ADP to ATP Convert some ADP to ATP Split H 2 O into Oxygen and High Energy Hydrogen ions (in the form of NADH + ). Split H 2 O into Oxygen and High Energy Hydrogen ions (in the form of NADH + ). Oxygen is released into the atmosphere. Oxygen is released into the atmosphere. ATP and Hydrogen ions are used to "fuel" the ATP and Hydrogen ions are used to "fuel" the Dark Reactions

Photosynthesis Dark Reactions One atom of Oxygen is split from CO 2. This atom combines with 2 Hydrogen ions to form H 2 O. Remaining Carbon and Oxygen group combine with remaining Hydrogen ions to enter the Calvin Cycle and eventually form Glucose (C 6 H 12 O 6 ).

Photosynthesis Hydrogen ions (NADH)

Cellular Respiration The process of converting stored chemical energy in food molecules to chemical energy in the form of ATP that is usable for all cellular activities. The process of converting stored chemical energy in food molecules to chemical energy in the form of ATP that is usable for all cellular activities. A two stage process: A two stage process: Stage 1 is ALWAYS glycolysis Stage 1 is ALWAYS glycolysis Stage 2 is either Stage 2 is either Aerobic respiration (with oxygen) Aerobic respiration (with oxygen) Anaerobic respiration (without oxygen) Anaerobic respiration (without oxygen)

Cellular Respiration ALL living organisms carry on cellular respiration to provide energy for life processes. ALL living organisms carry on cellular respiration to provide energy for life processes. Autotrophs carry on cellular respiration Autotrophs carry on cellular respiration Heterotrophs carry on cellular respiration Heterotrophs carry on cellular respiration REMEMBER … even plants carry on cellular respiration REMEMBER … even plants carry on cellular respiration

Cellular Respiration GLYCOLYSIS Glycolysis is the breakdown of glucose to form 2 molecules of pyruvate. This process occurs in the cytoplasm of the cell. This process uses 2 molecules of ATP and makes 4 molecules of ATP to yield a total gain of 2 ATP. CELLULAR RESPIRATION ALWAYS BEGINS WITH GLYCOLYSIS!!!!!

The second stage of cellular respiration will take one of two paths depending on whether oxygen is present or absent in the cell. The second stage of cellular respiration will take one of two paths depending on whether oxygen is present or absent in the cell. If oxygen is present, aerobic respiration occurs in the mitochondrion of the cell producing a LOT of ATP. If oxygen is present, aerobic respiration occurs in the mitochondrion of the cell producing a LOT of ATP. If oxygen is not present, anaerobic respiration occurs in the cytoplasm of the cell producing NO additional ATP. If oxygen is not present, anaerobic respiration occurs in the cytoplasm of the cell producing NO additional ATP.

Cellular Respiration AEROBIC RESPIRATION AEROBIC RESPIRATION Takes place in the mitochondria of the cell Takes place in the mitochondria of the cell Pyruvate produced in glycolysis enters the mitochondria and a carbon molecule is removed. This carbon combines with oxygen to produce a molecule of CO 2. Pyruvate produced in glycolysis enters the mitochondria and a carbon molecule is removed. This carbon combines with oxygen to produce a molecule of CO 2. The remaining portion of the pyruvate is now called an acetyl group. It combines with a molecule called Coenzyme-A to form a molecule called acetyl-CoA The remaining portion of the pyruvate is now called an acetyl group. It combines with a molecule called Coenzyme-A to form a molecule called acetyl-CoA

Cellular Respiration AEROBIC RESPIRATION AEROBIC RESPIRATION Acetyl-CoA enters the Krebs Cycle. Acetyl-CoA enters the Krebs Cycle. The Krebs Cycle will produce 2 more ATP, and will "energize" 3 molecules of NADH and 1 molecule of FADH 2. The Krebs Cycle will produce 2 more ATP, and will "energize" 3 molecules of NADH and 1 molecule of FADH 2. The NADH and FADH 2 enter an electron transport chain in the mitochondrial membrane to produce another 34 ATP. The NADH and FADH 2 enter an electron transport chain in the mitochondrial membrane to produce another 34 ATP. Oxygen is needed to keep the electron transport chain running. It combines with Hydrogen to form water. Oxygen is needed to keep the electron transport chain running. It combines with Hydrogen to form water.

Cellular Respiration AEROBIC RESPIRATION Total ATP produced: Glycolysis = 2 ATP Krebs Cycle = 2 ATP Electron Transport Chain = 34 ATP Grand Total = 38 ATP C6H12O O2 + 6 H2O→6 CO H2O + 38 ATP

ANAEROBIC RESPIRATION ANAEROBIC RESPIRATION If oxygen is not present in the cell, the electron transport chain will not function. Instead of entering the Krebs Cycle, the pyruvate produced in glycolysis will undergo fermentation. If oxygen is not present in the cell, the electron transport chain will not function. Instead of entering the Krebs Cycle, the pyruvate produced in glycolysis will undergo fermentation. Two important types of fermentation are Two important types of fermentation are Lactic acid fermentation Lactic acid fermentation Alcoholic fermentation Alcoholic fermentation

Cellular Respiration ANAEROBIC RESPIRATION ANAEROBIC RESPIRATION The end result of lactic acid fermentation is lactic acid (also called lactate) The end result of lactic acid fermentation is lactic acid (also called lactate) Some bacteria and fungi act anaerobically on sugars in foods to produce other foods including: Some bacteria and fungi act anaerobically on sugars in foods to produce other foods including: cheese cheese yogurt yogurt buttermilk buttermilk Low levels of oxygen in muscle cells during heavy exercise results in anaerobic respiration and the buildup of lactic acid. This is what causes your muscles to become sore. Low levels of oxygen in muscle cells during heavy exercise results in anaerobic respiration and the buildup of lactic acid. This is what causes your muscles to become sore.

Cellular Respiration ANAEROBIC RESPIRATION The end result of alcoholic fermentation is ethyl alcohol (ethanol) and carbon dioxide. Many yeasts ferment (anaerobic respiration) the sugars in grains to produce other useful items: baked goods such as bread that require dough to rise. b beer and wine (12% alcohol or less) "hard" liquors (require further distillation to achieve alcohol concentrations >12%) fuel for engines.

Cellular Respiration ANAEROBIC RESPIRATION ANAEROBIC RESPIRATION Anaerobic respiration does not produce any more ATP for the cell to use. Anaerobic respiration does not produce any more ATP for the cell to use. The total yield of ATP from anaerobic respiration is the 2 ATP produced during glycolysis. The total yield of ATP from anaerobic respiration is the 2 ATP produced during glycolysis. The "extra" ATP that could have been produced is still stored in the end products of fermentation. The "extra" ATP that could have been produced is still stored in the end products of fermentation. Ethanol is a race car fuel Ethanol is a race car fuel Cheese is a high energy food Cheese is a high energy food