PHOTOSYNTHESIS: Converting solar energy into chemical energy (SUGARS). CELLS AND ENERGY Part 1 PHOTOSYNTHESIS: Converting solar energy into chemical energy (SUGARS).

By the end of this lecture you will be able to: Appreciate that the Sun provides most of the energy needed for life on Earth. Explain why photosynthesis is so important to energy and material flow for life on earth. Know why plants tend to be green in appearance. Equate the organelle of photosynthesis in eukaryotes with the chloroplast. Describe the organization of the chloroplast. Understand that photosynthesis is a two part process composed of the light-dependent reactions and the light independent reactions (i.e. Calvin Cycle). Tell where the light reactions and the CO2 fixation reactions occur in the chloroplast. Define chlorophylls. Describe the process of photosynthesis.

THE BASICS OF PHOTOSYNTHESIS Almost all plants are photosynthetic autotrophs, as are some bacteria and protists Autotrophs are organisms that generate their own organic matter (sugars) through photosynthesis Sunlight energy is transformed to energy stored in the form of chemical bonds (c) Euglena (d) Cyanobacteria (b) Kelp (a) Mosses, ferns, and flowering plants

Organisms that produce their own chemical energy (sugars). What are Autotrophs? Organisms that produce their own chemical energy (sugars).

Why is Photosynthesis so Important to Your Life and all Life on This Planet? Photosynthetic organisms, such as plants, some bacteria and protists are the MAIN SOURCES of chemical energy for most organisms on Earth. Animals that eat other plant eating animals, and bacteria and fungi that decompose other organisms, get their chemical energy INDIRECTLY from plants.

THE FOOD WEB

WHY ARE PLANTS GREEN? It's not that easy bein' green Having to spend each day the color of the leaves When I think it could be nicer being red or yellow or gold Or something much more colorful like that… Kermit the Frog

Electromagnetic Spectrum and Visible Light Gamma rays Infrared & Microwaves X-rays UV Radio waves Visible light Wavelength (nm)

WHY ARE PLANTS GREEN? Different wavelengths of visible light are seen by the human eye as different colors. Gamma rays X-rays UV Infrared Micro- waves Radio waves Visible light Wavelength (nm)

Spectrum of Visible Light Activity Point the SPECTROSCOPE toward the lights and view the visible colors, which are the wavelengths of visible light the human eye can perceive.

What is the Spectrum of Visible Light that you can see? Wavelengths from 380 to 700

Why are plants green? Reflected light Plants are green because the green wavelength is REFLECTED, not absorbed. All other colors are absorbed.

Plants are green because they REFLECT the GREEN wavelengths. Why are plants green? Plants are green because they REFLECT the GREEN wavelengths.

Where Does Photosynthesis Take Place in Plants? Mainly occurs in the leaves of plants. Leaves contain organelles – CHLOROPLASTS Chloroplasts contain pigments called CHLOROPHYLL, which give the leaves their green color.

The location and structure of chloroplasts LEAF CROSS SECTION MESOPHYLL CELL LEAF Chloroplast Mesophyll CHLOROPLAST Intermembrane space Outer membrane Inner membrane Thylakoid compartment Thylakoid Stroma Granum Grana

CHLOROPHYLL – the pigment that absorbs light (solar energy) and reflects green light.

THYLAKOID Thylakoid Membrane Granum Thylakoid Space “LUMEN”

Photosynthesis takes place in the leaves of plants. What part of plants does Photosynthesis take place? Photosynthesis takes place in the leaves of plants.