Nutrition Autotroph Obtaining and processing food to a usable form Synthesizes organic compounds (food) Algae….chlorophyll in cell membrane Phototroph – Photosynthesis Plants, Algae

Where does the energy come from that sustains all life? Photosynthesis Where does the energy come from that sustains all life? The Sun!!

Importances of Photosynthesis Autotrophic Nutrition Process that converts inorganic compounds to organic compounds Converts light energy to chemical bond energy Importances of Photosynthesis Venus flytrap…..nitrogen poor soil, need to trap insects 1) Produces organic compounds (food) 2) Produces most atmospheric oxygen

Chlorophyll Chloroplast Pigment that absorbs sunlight Organelle in plants that contains chlorophyll and is the site of photosynthesis

Chloroplasts Figure: 06-01 Title: An overview of photosynthetic structures. Caption:

Chlorophyll Light Absorption Best Worst Blue & Red Green & Yellow

What you see are the UNUSED TRANSMITTED COLORS OF LIGHT What you see are the UNUSED TRANSMITTED COLORS OF LIGHT. Absorbed colors will not be seen!!!!

Chromatography Process to separate pigments based on charge These chlorophyll and colored pigments may be separated according to their various chemical charges by a technique known as chromatography.  In this technique, a mixture of plant pigments is separated by placing a drop or two of pigment on a special paper called chromatography paper which is dipped in a chemical allowing the different plant pigments to move based on their charges.

Why leaves are green?: interaction of light with chloroplasts

Photosynthesis What occurs during the overall reaction? Carbon dioxide and water in the presence of sunlight are converted to the organic compound glucose and to oxygen. sunlight 6CO2 Circle organic, underline inorganic/label + 6H2O C6H12O6 6O2 + sunlight 6CO2 + 12H2O C6H12O6 + 6H2O + 6O2

Chloroplast Structure Grana: Stack of membranes disks (thylakoids) Chlorophyll and enzymes embedded Stroma: Region around grana

Chloroplast Stroma Thylakoid Grana (stacks of thylakoids) contain chlorophyll Grana (stacks of thylakoids)

Photosynthesis: An Overview Light O2 Sugars CO2 Chloroplast Chloroplast NADP+ ADP + P Light- Dependent Reactions Calvin Cycle ATP NADPH

Light Reaction Dark Reaction Photosynthesis Photochemical Rxn Carbon Fixation Rxn - Occurs in light - Occurs 24 hours/day - Grana - Stroma

Light Reaction Light energy is absorbed by the chlorophyll in the grana 2) Most energy is used for photolysis of water 2H2O  2H2 + O2 3) H2 released is transferred to Hydrogen carriers NADP+ + H+ NADPH (use for NRG) 4) Some light energy produces ATP directly to be used in the dark reactions

Dark Reaction H atoms from light reaction combine with CO2 from atmosphere producing G3P/PGAL (3 carbon sugar) 2) G3P/PGAL used to synthesize glucose and other compounds

2 H2O 2 H O2 Photolysis Light Cycle Makes Oxygen to release to environment as waste O2 Sunlight 2 H2O 2 H Makes hydrogen atoms that will be used in the DARK CYCLE (NADPH) Photolysis

The Dark Cycle (Calvin Cycle) CO2 From the air (animals) H From light cycle G3P/PGAL then…. glucose (C6H12O6)

Leaf Adaptation 1) Large surface area: Maximum absorption of light 2) Cuticle: Waxy covering on epidermis (top layer) Protects against: 1) Excess water loss 2) Mechanical injury 3) Fungal growth

Cuticle

openings in cuticle and epidermis 3) Stomates: openings in cuticle and epidermis - allows exchange of CO2 and O2 - releases excess water 4) Guard Cells: Surrounds stomates - regulates size of stomates 5) Palisade Layer: Stomates and guard cells…..regulation/homeostasis Elongated cells below epidermis - contain most chloroplasts - major site of photosynthesis in leaf

Epidermis Palisade Layer Epidermis Stomate Guard Cell

Leaf Parts Aid Photosynthesis Guard Cells Stomates

Conducting Tissue Located in palisade layer, 6) Chloroplast: spongy layer and guard cells. 6) Chloroplast: Conducting Tissue 7) Veins: Xylem: transports water and dissolved materials Phloem: transports synthesized materials (glucose) “food”

Conducting Tissue Sheath cells

Factors Affecting Rate of Photosynthesis Light intensity Carbon dioxide concentration Temperature Enzymes denature at certain temp….decrease rate