ATP Adenosine Triphosphate (ATP) - One of the principal chemical compounds that living things use to store and release energy ATP Made up of: 1. 2. 3. Adenine 5-carbon sugar called ribose Three phosphate groups (The key to ATP's ability to store and release energy.) ATP vs. ADP Adenosine Diphosphate – ATP minus one phosphate group ATP – contains three phosphate groups (tri = three) ADP – contains two phosphate groups (di = two) Adenosine Triphosphate Adenosine Diphosphate ATP and Energy ATP is used by all types of cells as their basic energy source. Energy is released when a phosphate is removed. Where does the mass of a plant come from? Photosynthesis Heterotroph Heterotroph - Organism that obtains energy from the foods it consumes; also called a consumer Autotroph Autotroph - Organism that can capture energy from sunlight or chemicals and use it to produce its own food from inorganic compounds; also called a producer. Which organisms go through Photosynthesis? Plants Photosynthetic Bacteria (ex. Cyanobacteria) Some Protists (ex. Algae) Photosynthesis Photosynthesis - Process by which plants and some other organisms use light energy to convert water and carbon dioxide into oxygen and high-energy carbohydrates such as sugars and starches. Photosynthesis Needed (Reactants): 1. 2. 3. Light Water Carbon dioxide Given Off (Products): 1. 2. Sugars Oxygen Chlorophyll Photosynthesis also requires chlorophyll, a molecule located in chloroplasts. Chlorophyll - Principal pigment of plants and other photosynthetic organisms; captures light energy Chlorophyll Plants gather the sun's energy with lightabsorbing molecules called pigments. The plants' principal pigments are called chlorophyll. Chlorophyll does not absorb light well in the green region of the spectrum therefore green light is reflected by leaves (this is why plants look green). Chloroplast Vocabulary Thylakoids - Saclike photosynthetic membrane found in chloroplasts. (where chlorophyll is found) Stroma - Region outside the thylakoid membranes in chloroplasts Two Sets of Reactions in Photosynthesis 2. The Light-Dependent Reactions The Light-Independent Reactions (akaCalvin Cycle) These two chemical reactions work together! 1. Light-Dependent Reactions Takes place within the thylakoid membranes Requires light Requires: Water, ADP, and NADP+ Produce: Oxygen, ATP, and NADPH Electron Carriers within the Light Dependent reaction Inside the thylakoid, electrons within the chlorophyll become “excited” (gain energy) from the sunlight. Now that they have all this energy they require a carrier molecule : NADP+. NADP+ NADP+ As soon as this carrier molecule NADP+ accepts the energy (from the electrons) it converts the NADP+ into NADPH. This transfer of electrons and energy is called the Electron Transport Chain (ETC) Light Dependent Reactions The sunlight breaks each water molecule into : electrons H+ ions (released into thylakoid membrane) Oxygen atoms (released into the air) Light Dependent Reactions As electrons are passed from chlorophyll to NADP+, more hydrogen ions are pumped across the membrane. Inside of the membrane fills up with positively charged hydrogen ions. Outside of thylakoid membrane becomes negatively charged. The difference in charges across the membrane provides the energy to make ATP. The H+ ions are important! Light Dependent Reactions ATP Synthase - Large protein/enzyme that uses energy from H+ ions to bind ADP and a phosphate group together to produce ATP. Spans the thylakoid membrane and allows H+ ions to pass through it. Overall: Produce oxygen gas and convert ADP and NADP+ into the energy carriers ATP and NADPH. http://www.youtube.com/watch?v=eY1ReqiY wYs The Light-Independent Reactions (Calvin Cycle) Takes place in the stroma Uses ATP and NADPH from the lightdependent reactions to produce high-energy sugars. Calvin Cycle Uses six molecules of carbon dioxide to produce one single glucose molecule. Energy for this conversion comes from ATP and high-energy electrons from NADPH. Factors Affecting Photosynthesis 1. Water 2. Temperature 3. A shortage of water can slow or even stop photosynthesis. Photosynthesis depends on enzymes that function best between 0°C and 35°C. Intensity of Light Increasing light intensity increases the rate of photosynthesis...but a plant will reach a maximum rate.