Storing Energy from the Sun: Photosynthesis

Plant Impostors In The News

Photosynthesis Process that captures energy from the sun Energy stored in carbohydrates Oxygen is byproduct

Sunlight Electromagnetic energy (radiation) Packets of energy (photons) Range of wavelengths

Plant Pigments Found in chloroplasts Absorb some visible wavelengths

Plant Pigments Carotenoids – absorb photons of green, blue & violet wavelengths Chlorophylls – absorb photons of red & violet-blue wavelengths

Autotrophs Produce their own food Photosynthesis Chemosynthesis Cyanobacteria

Photosynthetic Autotrophs Solar energy powers glucose synthesis Uses Carbon dioxide Water Captured energy Produces Glucose Oxygen

Heterotrophs Consume other organisms Cannot produce their own food Food ultimately comes from autotrophs

Cellular Respiration Process that unlocks stored energy Nutrient molecules store energy in bonds Chemical reactions produce ATP ATP provides cellular energy Skunk cabbage using metabolic heat to melt snow

Aerobic Cellular Respiration Oxygen dependent Byproducts Raw materials for photosynthesis Carbon dioxide Water

Carbohydrates 6CO2 + 6H2O C2H12O6 + 6O2 Photosynthetic stored energy product energy 6CO2 + 6H2O C2H12O6 + 6O2 Carbon dioxide + water with energy yields glucose + oxygen

Chemical Reactions for Photosynthesis Light dependent reactions Light independent reactions

Light Dependent Reactions ATP & NADPH formed NADPH Nicotinamide adenine dinucleotide phosphate An electron carrier Molecules store energy from sun

Electron Carrier Transfer from one molecule to another Produce molecules that carry energy

Light Independent Reactions Provides for formation of glucose Uses ATP & NADPH No direct light involvement

Chloroplasts Organelles Site of photosynthesis Light dependent reactions on membrane Light independent reactions in fluid

Chloroplasts Probably evolved from symbiotic bacteria Thylakoids = internal membranes Grana = stacks of thylacoids Stroma = fluid around thylakoid

Summary of Photosynthesis Light dependent reactions change energy from Sun into chemical energy Energy is held in ATP & NADPH Chemical energy from ATP & NADPH is transferred to sugars Sugars used to fuel activities of life

Reactions to Store Energy Pigment molecules funnel energy to chlorophyll Two stage photosystem to carry out light dependent reactions Photosystems work together to harvest energy

Pigment Molecules On thylakoid membranes Chlorophyl (chlorophyl a) Capture & funnel photon energy

Photosystems Electrons boosted to higher level Photosystem I Energy transferred to P700 molecule Photosystem II Energy transferred to P680 molecule

Electron Flow in Photosynthesis

Electron Flow in Light-Dependent Reactions

Carbohydrate Production: Light-Independent Reactions