130 likes | 223 Views
Photosynthesis Part 1. Pages 108 to 111. Autotrophs. Name some common producers Plants, algae, some protists , cyanobacteria Define photoautotroph An organism that uses light energy to produce food Define chemoautotroph An organism that uses chemical energy to produce food. Fig. 10-2.
E N D
Photosynthesis Part 1 Pages 108 to 111
Autotrophs • Name some common producers • Plants, algae, some protists, cyanobacteria • Define photoautotroph • An organism that uses light energy to produce food • Define chemoautotroph • An organism that uses chemical energy to produce food
Fig. 10-2 (a) Plants (c) Unicellular protist 10 µm (e) Purple sulfur bacteria 1.5 µm (b) Multicellular alga (d) Cyanobacteria 40 µm
Location of photosynthesis • State the organelle of photosynthesis • Chloroplast • Where are chloroplasts concentrated in plants? • The green tissue on the interior of the leaf • Mesolphyll
Fig. 10-3a Leaf crosssection Vein Mesophyll Stomata CO2 O2 Chloroplast Mesophyll cell 5 µm
Gas Exchange • Explain how gases are exchanged between the plant and the environment. • Stoma are openings in the epidermis of leaves • Guard cells surround the stoma and they regulate the opening & closing of the stoma • When open, CO2 can enter while O2 and H2O can exit
Fig. 10-3b Chloroplast Structure of the chloroplast Thylakoid is site of light reactions Stroma is site of Calvin Cycle Outer membrane Thylakoid Intermembrane space Stroma Granum Thylakoid Space (lumen) Inner membrane 1 µm
Plants produce O2 by splitting H2O • 1950’s – scientists used heavy isotope of oxygen (18O) to follow oxygen through photosynthesis. • Tagged oxygen of CO2 and found no tagged O2 given off • Tagged O2 of H2O and found tagged O2 given off
Fig. 10-4 6 CO2 12 H2O Reactants: 6 H2O 6 O2 C6H12O6 Products:
Photosynthesis is a Redox Reaction • Equation • 6CO2 + 6H2O Light C6H12O6 + 6O2 • Redox reaction of photosynthesis • Oxidized: • H2O to O2 • Reduced: • CO2 to C6H12O6
Overview of Photosynthesis • Photosynthesis consists of the light reactions (photo – absorbs light energy) and the Calvin cycle (synthesis – makes sugar)
2 stages of photosynthesis Light Reactions • Takes place in the thylakoids • Split H2O • Release O2 • Reduce NADP+ to NADPH • Produce ATP via photophosphorylation • Takes place in the stroma • Forms sugar using • CO2 from atmosphere • ATP and NADPH from light reactions • Starts with carbon fixation Calvin Cycle
Fig. 10-5-4 CO2 H2O Light NADP+ ADP + P i Calvin Cycle Light Reactions ATP NADPH Chloroplast [CH2O] (sugar) O2