Photosynthesis Notes Biology Unit 05 Lesson 01

Chemosynthesis  Chemosynthesis uses energy released from chemical reactions to produce food for organisms.  Organisms that carry out chemosynthesis are microbes (bacteria) that live far from the Sun, such as deep on the ocean floor.

Which Organisms Carry Out Photosynthesis?  Autotrophs such as plants and some protists

Photosynthesis  Photosynthesis is the cellular process in which autotrophs capture light energy and convert it to chemical energy (glucose) using carbon dioxide and water.

Equation for Photosynthesis  6CO 2 + 6H 2 O + Light Energy  C 6 H 12 O 6 + 6O 2  Carbon Dioxide + Water + Light Energy  Glucose (sugar) + Oxygen

Reactants & Products of Photosynthesis REACTANTSPRODUCTS Carbon Dioxide Glucose (sugar) Water Oxygen Light Energy

Where Does Photosynthesis Occur?  Chloroplasts  Contain chlorophyll in plant cells or autotrophs

Cellular respiration  What is it?  the process in which organisms acquire energy from food. (Release of chemical energy for cellular use.)  The chemical equation for respiration is:  C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O  Glucose + Oxygen Carbon Dioxide + Water  Where does it occur?  Starts in cytoplasm, finishes in Mitochondria, all cells  TWO parts  Glycolysis, respiration/fermentation

STEP 1: Glycolysis Breaks the glucose into two 3-carbon sugars called pyruvate  STEP 2: OR  Respiration (aerobic)  Krebs cycle + Electron Transport Chain  Breaks down pyruvate into ATP using Oxygen  Produces 38 ATP molecules  Fermentation (anaerobic)  Lactic acid (animals) or alcoholic (plants)  Breaks down pyruvate into ATP without Oxygen  Produces 2 ATP molecules

Reactants & Products of Photosynthesis and respiration REACTANTSPRODUCTS Phot Resp

Light Dependent Reaction  Occurs in the thylakoid  Water is absorbed through roots.  Sunlight enters the chloroplast, causing H 2 O molecules to split.  O 2 leaves as a waste product through the stomata.  NADP + picks up the H + ions (becoming NADPH) and moves them to the stroma for the light independent reaction (Calvin cycle).

Light Independent Reaction – Calvin Cycle  Carbon dioxide from the atmosphere enters  H + breaks off from NADPH  NADP + returns to the Light Dependent Reaction  Carbon dioxide becomes “fixed” with the H + producing the glucose molecule C 6 H 12 O 6.