A. Photosynthesis plants trap the sun s energy and store it in molecules of glucose B. Cellular Respiration Plants and animal cells release energy stored in glucose and store it to use later C.Adenosine Triphosphate the molecule where the energy is stored
ATP (Adenosine Triphosphate) Provides stored energy for cell activities: transport, division, movement, etc. Made through the addition of energy and phosphate to Adenosine Diphosphate (ADP)
ATP ADP Cycle ATP is formed Energy is added with a phosphate to ADP Energy is released with a phosphate ADP is formed
Photosynthesis Two phases: 1. Light dependent reactions 2. Light independent reactions 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2
Photosynthesis takes place in the chloroplast Elodea cells with small circular chloroplasts!
Grana: stack of thylakoid disks Thylakoids: sacs containing chlorophyll Stroma: the region outside the grana Chlorophyll a & b absorb all wavelengths of light except green. therefore, the leaves appear green!
Steps of Photosynthesis Light Dependent Reactions (grana) 1. Light energy is trapped by the chlorophyll. 2. Energy boosts electrons with absorbed energy to a higher energy level. 3. Electron transport chain passes electrons from molecule to molecule releasing energy.
4. Energy is used to either split molecules of water or form ATP. 5. Hydrogen from the water molecules is picked up by NADP + forming NADPH which is used in the light dependent reactions. 6. Energy from the water molecules is stored in molecules of ATP
Steps of Photosynthesis(cont.) Light Independent Reactions (stroma) 1. Also called the Calvin Cycle. 2. Carbon dioxide is broken down. 3. NADPH releases hydrogen. 4. ATP releases P and energy 5. Glucose (6-carbon sugar) is formed after six times through the cycle.
Aerobic Cellular Respiration Three stages: 1. Glycolysis cytoplasm/anaerobic 2. Krebs Cycle(Citric Acid Cycle) mitochondria/aerobic 3. Electron Transport Chain mitochondria/aerobic
Cellular respiration takes place in the mitchondria.
Glycolysis 1. Two molecules of ATP start glycolysis. 2. Glucose is broken down into two molecules of Pyruvic Acid. 3. Four ATP are produced. 4. Net profit of two ATP 5. Pyruvic acid moves to the mitchondria where they lose a molecule of CO2 go form acetyl-coa
For the sake of clarity this animation of glycolysis does not show the enzymes that catalyze each reaction, and only the carbon skeletons of the intermediates are shown. You should note the major stages in glycolysis, especially the changes in energy content. http://www.science.smith.edu/departments/biology/ Bio231/glycolysis.html
Krebs Cycle 1. Two carbon Acetyl-CoA reacts with a four carbon compound. 2. A molecule of CO2 is released reducing it to a five carbon compound. 3. NADH is produced. 4. Another molecule of CO2 is released and a four carbon compound is produced.
Krebs Cycle (cont.) 5. The four carbon compound undergoes a series of reactions. 6. One molecule of ATP and NADH are produced. 7. The carriers FADH and NADH are formed. 8. Cycle starts over.
This animation of the Tricarboxylic acid cycle is designed to show the major events. For the sake of clarity the enzymes at each step have been omitted and only the carbon skeletons of the intermediates are shown. http://www.science.smith.edu/departments/biology/bi o231/krebs.html
Electron Transport Chain 1. NADH and FADH2 pass energized electrons from protein to protein. 2. Energy is used to directly form ATP 3. Oxygen picks up the remaining Hydrogen to form water.
Summary of Aerobic Cellular Respiration Glucose Glycolysis Electron Transport Chain Pyruvic Acid Carbon dioxide Water 38 ATP Krebs Cycle
ANAEROBIC CELLULAR RESPIRATION BUT WHAT IF NO OXYGEN IS PRESENT??? Glycolysis is the same because oxygen is not necessary to run this step.
After glycolysis, cells that do not have O 2 present must undergo anaerobic cellular respiration. Two possibilities: Lactic acid fermentation Alcoholic fermentation
Lactic Acid Fermentation In animal cells, for short periods when O 2 is not available. 1. Pyruvic acid can only be broken down into lactic acid and 2 ATP. 2. Causes cramping in muscle cells encouraging.
Alcoholic Fermentation 1. In bacteria and yeast cells who do not require oxygen for survival. 2. Pyruvic acid can only be broken down into ethyl alcohol, carbon dioxide and 2 ATP. 3. Important in food industry.
Photosynthesis Food accumulated Carbon dioxide taken in Oxygen given off Produces glucose from PGAL Goes on only in light Occurs only on presence of chlorophyll Cellular Respiration Food broken down Carbon dioxide given off Oxygen taken in Produces CO 2 and H 2 O Goes on day and night Occurs in all living cells
Big Picture Summary Phase 1: Light- Dependent Reactions In Thylakoid Membrane Phase 2: Light- Independent Reactions In Stroma Uses: Light + H 2 O Uses: NADPH + ATP + CO 2 To Make: To Make: O 2 + NADPH + ATP C 6 H 12 O 6
What kinds of factors affect photosynthesis? What? Light intensity Water Temperature How? Affects the rate at which photosynthesis occurs Shortage of water will slow or stop photosynthesis Enzymes can be damaged if the temp. is too high or low