Photosynthesis
Parts of the Leaf sites of photosynthesis Chloroplasts sites of photosynthesis contains chlorophyll - green pigment (stem, unripe fruit, LEAVES) Light energy is absorbed by the chlorophyll which drives the synthesis of organic molecules
Stomata (stoma): site of gas exchange - CO2 in the leaf and O2 /water vapour out the leaf
Roots: water is delivered to the leaves vessels (xylem)and sugar is exported to the roots via the vessels (phloem)
Structures of a Chloroplast Stroma: fluid within the chloroplast Thylakoid: flattened membranes that contains chlorophyll Grana: stacked thylakoids
Inside a chloroplast
Chemical Equation 6CO2 + 6H2O + light C6H12O6 + 6O2 Or reduced equation: CO2 + H2O + light CH2O + O2
Two Stages of Photosynthesis Light reactions (photo) Calvin cycle (synthesis) Light Reactions: -occurs in the thylakoid of chloroplasts -light absorbed by chlorophyll drives a transfer of electrons and hydrogen from water to an electron acceptor NADP+
-NADP+ temporarily stores energized electrons -water is split in the process and therefore the light reaction of photosynthesis gives of oxygen as a by product -NADP+ gets reduced (gains 2 electrons and an hydrogen ion) by solar power and forms NADPH this generates ATP by powering a phosphate to ADP
-This synthesis of ATP ( P + ADP ) is called photophosphorylation -This synthesis of ATP ( P + ADP ) is called photophosphorylation. ** Light energy is converted to chemical energy in the form of two compounds: 1. NADPH (energized electrons) 2. ATP (energy currency of cells)
Calvin Cycle -also known as dark reactions or light independent reactions -YET occurs in the light because it is powered by ATP and NADPH which require light -process involves synthesis of sugar (carbohydrate) -occurs in the stroma(fluid)
-Carbon fixation: incorporating CO2 from the air into an organic compound -the fixed carbon is then reduced (gains electrons) to form a carbohydrate -fixed carbon is able to be reduced due to the NADPH reducing power and ATP produced by the light reaction