Photosynthesis!!!!

The Pathway of energy in living organisms Light energy from the sun Chemical energy stored in glucose, fats, or carbohydrates Chemical energy for use in the form of ATP photosynthesis cellular respiration Autotrophs = Organisms that make their own food (usually from photosynthesis). Heterotrophs = Organisms that can't make their own food so they take in food produced by autotrophs (by eating autotrophs or organisms that eat autotrophs)

Overview of Cellular Respiration The energy released from the catabolism of glucose is used to make ATP from ADP ADP + P + energy ATP

Overview of Photosynthesis The energy from the sun is used to reduce CO 2 to produce glucose

Figure 10.3 Tracking atoms through photosynthesis

Energy flow and chemical recycling in ecosystems Catabolism Anabolism

Photoautotrophs: other organisms besides plants can photosynthesize

12 H 2 O The overall reaction in photosynthesis: 6CO Light energy C 6 H 12 O 6 6O 2 6 H 2 O + Photosynthesis is divided into two parts Two components: Light energy H2OH2O O2O2 Light-dependent reactions Chemical energy (ATP, NADPH) Chemical energy (ATP, NADPH) CO 2 Light-independent reactions Chemical energy (C 6 H 12 O 6 ) Energy HarvestSynthesis

The energy from light is captured and converted in chloroplasts Chlorophyll and accessory pigments capture electromagnetic energy by absorbing photons of light.

Leaves contain millions of chloroplasts Leaf cross-section Cells containing chloroplasts Chlorophyll is found and Photosynthesis takes place in the chloroplasts of plant cells

Outer membrane Inner membrane Stroma Thylakoids Granum Outer membrane Inner membrane Stroma Granum Thylakoid Chloroplasts are highly structured, membrane-rich organelles

Figure 10.9 Location and structure of chlorophyll molecules in plants

The energy from the sun arrives on earth in the form of light energy, a type of electromagnetic radiation

How objects appear different colors White light is a mixture of all wavelengths (and colors) of light White light Green light Is reflected and transmitted Red and blue light Is absorbed We see the Plant as green

Figure 10.6 Why leaves are green: interaction of light with chloroplasts

The wavelength of light a compound absorbs can be determined by a spectrophotometer

Amount of light absorbed Chlorophyll a Chlorophyll b Carotenoids Wavelength of light (nm) Different plant pigments absorb different wavelengths of light.

e–e– e–e– Photons 012 Energy state of electrons in chlorophyll Electrons can be promoted to discrete high- energy states: Blue photons excite electrons to a higher energy state Red photons excite electrons to a high-energy state When a photon of light strikes chlorophyll, an electron can be promoted to a higher energy state

Figure Excitation of isolated chlorophyll by light

Photosynthesis Light Dependent Reaction –Energy from the high energy electron of chlorophyll is used to make ATP and NADPH Light Independent Reaction (Calvin Cycle) –ATP and NADPH is used to make glucose from CO 2

Figure 10.4 An overview of photosynthesis: cooperation of the light reactions and the Calvin cycle (Layer 1)

Figure 10.4 An overview of photosynthesis: cooperation of the light reactions and the Calvin cycle (Layer 2)

Figure 10.4 An overview of photosynthesis: cooperation of the light reactions and the Calvin cycle (Layer 3)