stomate transpiration gas exchange

PHOTOSYNTHESIS!!

Photosynthesis Overview Energy for all life on Earth ultimately comes from photosynthesis. 6CO2 + 12H2O C6H12O6 + 6H2O + 6O2 Photosynthesis is carried out by: Cyanobacteria,Some protists,+ Land plants

Thylakoid membrane contains chloroplast H+ ATP Chloroplasts double membrane stroma fluid-filled interior thylakoid sacs grana stacks Thylakoid membrane contains chlorophyll molecules electron transport chain ATP synthase H+ gradient built up within thylakoid sac thylakoid outer membrane inner membrane granum stroma thylakoid A typical mesophyll cell has 30-40 chloroplasts, each about 2-4 microns by 4-7 microns long. Each chloroplast has two membranes around a central aqueous space, the stroma. In the stroma are membranous sacs, the thylakoids. These have an internal aqueous space, the thylakoid lumen or thylakoid space. Thylakoids may be stacked into columns called grana.

Pigments Pigments: molecules that absorb visible light Each pigment has a characteristic absorption spectrum, the range it is capable of absorbing. --chlorophyll a – primary pigment --chlorophyll b – secondary pigment -- carotenoids – accessory pigments

Why are plants green??

Two stages of photosynthesis: Light-dependent reactions Requires light as a source of energy Step 1: chlorophyll uses energy from sun to split water molecules Step 2: water molecules split into H & O Step 3: O2 released to atmosphere Step 4: chlorophyll stores some light energy in ATP

Photo phosphoryl ation Using light Adding a phospate group Light energy is used to add a high-energy phosphate group to a carrier molecule. A process

Light Reactions  produces ATP produces NADPH H2O ATP O2 light energy  + NADPH H2O sunlight produces ATP produces NADPH releases O2 as a waste product Energy Building Reactions NADPH ATP O2

Thylakoid Structure

Non-cyclic Same systems different drawings.

Light-Independent reactions (Calvin Cycle) Part of photosynthesis that doesn’t require light Step 1: hydrogen which split from H2O combines with CO2 using energy stored in ATP Step 2: this combination forms glucose (C6H12O6) Step 3: water is formed (byproduct)

Making Sugar The energy captured in the Lt-Dep is now used to fix CO2 and make sugar. Stage 1. Fix CO2 to RuBP. Stage 2. Generater PGAL then sugar. Stage 3. Regenerate RuBP.

Calvin Cycle  builds sugars uses ATP & NADPH recycles ADP & NADP CO2 C6H12O6  + NADP ATP NADPH ADP CO2 builds sugars uses ATP & NADPH recycles ADP & NADP back to make more ATP & NADPH ADP NADP Sugar Building Reactions NADPH ATP sugars

Putting it all together CO2 H2O C6H12O6 O2 light energy  + H2O CO2 Plants make both: energy ATP & NADPH sugars sunlight ADP NADP Energy Building Reactions Sugar Building Reactions NADPH ATP O2 sugars

*respiration occurs in plant cells also, when they need to release the energy stored in glucose

Energy cycle ATP Photosynthesis Cellular Respiration sun CO2 O2 H2O even though this equation is a bit of a lie… it makes a better story sun Photosynthesis CO2 H2O C6H12O6 O2 light energy  + H2O plants CO2 glucose O2 animals, plants CO2 H2O C6H12O6 O2 ATP energy  + Cellular Respiration ATP The Great Circle of Life,Mufasa!