Energy Transformations: Photosynthesis Cellular Respiration

ATP & ADP  ATP: Adenosine Triphosphate  adenine + ribose + 3 phosphates  Energy storing molecule,  only stores “E” for a few minutes  Source of all cell energy  When 1 phosphate group breaks off   “E” is released!!! Adenine Ribose 3 Phosphate groups

 ADP: Adenosine Diphosphate  Adenine + ribose + 2 phosphates  Molecule that results from ATP losing 1 “P”  Another “P” may be added later ADP ATP Energy Partially charged battery Fully charged battery Adenosine Diphosphate (ADP) + Phosphate Adenosine Triphosphate (ATP)

 You get energy from the food you eat.  Where does the energy in food come from?  Almost all of the energy in living systems needed for metabolism = SUN.  Figure 1 below shows how energy flows through living systems. 1. PLANT CONVERTS LIGHT “E” TO CHEMICAL “E” 2. ELK GETS “E” BY EATING PLANTS 3. LION GETS “E” FROM EATING ELK How much energy is passed on between trophic levels?

Overview Photosynthesis  Photosynthesis: Process using “E” from sunlight to convert water and CO 2  oxygen and carbohydrates (sugar; glucose) Two parts:  Light dependent reactions:  produce O 2 & converts ADP to ATP  Calvin cycle (dark reactions):  use ATP from light reactions to produce sugars Light Energy CO2 + H2O Sugars + O2 Chloroplast

The Stages of Photosynthesis  Stage 1 Energy is captured from sunlight.  Stage 2 Light energy is converted to chemical energy,  Temporarily stored in ATP and the “E” carrier molecule NADPH.  Stage 3 The chemical energy stored in ATP and NADPH powers the formation of organic compounds, GLUCOSE!  Using carbon dioxide!  Photosynthesis occurs in the chloroplasts of plant cells and algae and in the cell membrane of certain prokaryotes.

What are the substances used and produced during each stage of photosynthesis? UsedProduced Stage 1Light, water Oxygen, hydrogen ions, excited electrons Stage 2Electrons, hydrogen ionsATP, NADPH Stage 3ATP, NADPH, carbon dioxideOrganic compounds (GLUCOSE)

Why Do Plants Look Green?  Many people think that plants are green because plants use green light during photosynthesis. NOT  In fact, plants do NOT use green light  I nstead red and blue light are used. chlorophyll:  Plants look green because they contain chlorophyll:  reflects green and yellow light  absorbs blue and red light.

FORMULA for PHOTOSYNTHESIS: 6CO 2 + 6H 2 O --- C 6 H 12 O 6 + 6O 2 Chloroplast Light- Dependent Reactions Calvin Cycle Sugars

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Cellular Respiration   Respiration: process that releases energy by breaking down food when oxygen is present Formula: C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + energy

Fermentation Fermentation: respiration without oxygen present  Two types: Alcoholic Fermentation Alcoholic Fermentation:  form ethyl alcohol and CO 2 as waste products; used to make bread rise Lactic acid Fermentation Lactic acid Fermentation:  produces lactic acid in muscles when exercising without enough oxygen

The Stages of Cellular Respiration Stage 1 Stage 1 Glucose is broken down into pyruvate in a process known as GLYCOLYSIS! - 2 ATP are produced! Stage 2 Pyruvate is used to create NADH and FADH2 (both are energy carrier molecules) in a process known as the KREBS CYCLE! - NO ATP is produced in the Kreb’s Cycle! Stage 3 The chemical energy stored in NADH and FADH2 powers the formation of ATP in a process known as the ELECTRON TRANSPORT CHAIN! - 36 molecules of ATP are produced! 38 Total ATP are produced per glucose molecule during cellular respiration!!!

GLYCOLYSIS  What are the substances used and produced during each stage of cellular respiration? Stages of Cellular Respiration UsedProduced Stage 1Glucosepyruvate Stage 2pyruvateFADH 2, NADH, CO 2 Stage 3FADH 2, NADH, O 2 Energy (ATP), H 2 0

How Does Photosynthesis & Cellular Respiration Relate?  Almost opposite processes  Photosynthesis produces food (store)  Respiration breaks down food (releases)  Photosynthesis uses CO 2 and releases O 2  Respiration releases CO 2 and uses O 2

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