Photosynthesis Biology B

Overview 1. SUN 2. LIGHT ENERGY 3. PHOTOSYNTHESIS 5. RESPIRATION 6. ATP (CELL ENERGY) 4. CHEMICAL ENERGY

Energy Formation in Cells Organic Compounds & Oxygen ATP Energy for Life Carbon Dioxide & Water ADP and P

What is Photosynthesis? The process of photosynthesis is where organisms convert light energy into chemical energy to create products such as carbohydrates, sugars, and starches.

Where does it occur? In plants that are able to capture sunlight to make their own food (aka autotrophs.) The actual process occurs inside a cell’s chloroplasts.

What does it need? CARBON DIOXIDE (CO2) WATER  (H20) SUNLIGHT

What happens? (photosynthesis equation) Water Carbohydrates 6CO2 + 6H2O + ENERGY C6H12O6 + 6O2 Sunlight Carbon Dioxide Oxygen

How does it happen? The process of photosynthesis does not happen all at once. It is a very long process that is broken into 3 stages.

Stage 1 – Light Reactions Light is absorbed from the sun by the chloroplasts. H2O is taken into the cell as well. The light energy is used to split H20 into 3 separate parts (H, O2, and electrons.)

How does it work? Inside the chloroplasts are disk-shaped structures called thylakoids that contain different pigments.

How does it work? Pigments do the actual absorbing of light. a) Chlorophylls absorb red and blue light (produce green colors) b) Carotenoids absorb other colors (produce yellow and orange colors)

How does it work? Once the sunlight is captured it is used to split water (H20) into Hydrogen (H), Oxygen gas (O2), and free electrons. Oxygen gas (O2) is free to leave the plant and this is what animals use to breathe.

Stage 2 – Energy Storage Free electrons are passed from thylakoid to thylakoid until they reach an ADP molecule and turn it into an ATP. Hydrogen (H) molecules are passed from protein to protein until they reach a NADP+ molecule and then they become an NADPH.

How does it work? As electrons continuously get passed on this process is known as the electron transport chain.

Stage 3 – Dark Reactions The newly formed ATP and NADPH power the formation of carbohydrates, sugars, and starches. This is done by using CO2 as the starting material.

How does it work? Carbon Dioxide (CO2) enters the cell from the atmosphere and undergoes a process called the Calvin Cycle which creates simple sugars.

Summary of Stages Things used: Things made: Stage 1 Light and H2O O2, H, and electrons Stage 2 H and electrons ATP and NADPH Stage 3 ATP, NADPH, and CO2 Carbohydrates, sugars, starches

Factors that affect it? Light intensity Amount of CO2 available Temperature If any of these factors increase the photosynthesis process also increases and vice versa.

Photosynthesis H2O C6H12O6 CO2 + O2 + Calvin Cycle ATP ADP Energy Which splits water Calvin Cycle Light is Adsorbed By Chlorophyll ADP Chloroplast C6H12O6 O2 + Light Reaction Dark Reaction

* Light Independent Reactions Photosynthesis Capturing Energy from the Sun* Using energy to make ATP and NADPH* Using ATP and NADPH to make carbohydrates, sugars, and starches * * Light Dependent Reactions * Light Independent Reactions (Calvin Cycle)

Any Questions? Education is light, lack of it darkness. --Russian Proverb Education is the movement from darkness to light. --Bloom