Fig. 10-3a 5 µm Mesophyll cell Stomata CO 2 O2O2 Chloroplast Mesophyll Vein Leaf cross section

Fig. 10-1

Concept Map - Photosynthesis

Fig. 10-3b 1 µm Thylakoid space Chloroplast Granum Intermembrane space Inner membrane Outer membrane Stroma Thylakoid

Fig Porphyrin ring: light-absorbing “head” of molecule; note magnesium atom at center in chlorophyll a CH 3 Hydrocarbon tail: interacts with hydrophobic regions of proteins inside thylakoid membranes of chloroplasts; H atoms not shown CHO in chlorophyll b An appreciation of chlorophyll (remember, there are many forms of chlorophyll). Chlorophyll a & b are most common.

Reactants: Fig CO 2 Products: 12 H 2 O 6 O 2 6 H 2 O C 6 H 12 O 6

Oxidation & Reduction In photosynthesis:CO 2 is reduced or gains electrons to become glucose (high energy molecule) H 2 O is oxidized or loses electrons resulting in oxygen O = electrically neutral atom or molecule

When light strikes an object: Transmitted Absorbed (primarily red & blue light) Reflected (green light)

3 major events occur during photosynthesis 1.Absorption of light energy 2.Conversion of light energy to chemical (ATP & NADPH) 3.Storage of chemical energy in sugars These events occur during: -light rxn. (events 1,2) -Calvin Cycle. (event 3)

Photosynthetic Pigments: The Light Receptors Pigments are substances that absorb visible light Different pigments absorb different wavelengths Wavelengths that are not absorbed are reflected or transmitted Leaves appear green because chlorophyll reflects and transmits green light Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig Reflected light Absorbed light Light Chloroplast Transmitted light Granum

UV Fig Visible light Infrared Micro- waves Radio waves X-rays Gamma rays 10 3 m 1 m (10 9 nm) 10 6 nm 10 3 nm 1 nm 10 –3 nm 10 –5 nm nm Longer wavelength Lower energyHigher energy Shorter wavelength

Light Fig H2OH2O Chloroplast Light Reactions NADP + P ADP i + ATP NADPH O2O2 Calvin Cycle CO 2 [CH 2 O] (sugar)

Fig The specifics: Light Reaction Calvin Cycle

Fig Reflected light Absorbed light Light Chloroplast Transmitted light Granum

Fig Mill makes ATP e–e– NADPH Photon e–e– e–e– e–e– e–e– e–e– ATP Photosystem IIPhotosystem I e–e–

Fig Light Fd Cytochrome complex ADP + i H+H+ ATP P synthase To Calvin Cycle STROMA (low H + concentration) Thylakoid membrane THYLAKOID SPACE (high H + concentration) STROMA (low H + concentration) Photosystem II Photosystem I 4 H + Pq Pc Light NADP + reductase NADP + + H + NADPH +2 H + H2OH2O O2O2 e–e– e–e– 1/21/

Dr. Melvin Calvin ( ) Nobel Prize Dr. Calvin used a radioactive isotope (remember those),carbon 14, to determine the pathway of carbon in the process of photosynthesis. The Calvin Cycle shows how the intermediate products from the light reaction, ATP & NADPH, along with CO 2 go through a cyclic process producing various intermediate products that eventual lead to glucose production.