Energy Transfer Photosynthesis
Energy All living organisms use energy. Energy is needed for metabolism to function. When organisms use energy they use it in the chemical form, ATP (adenosine triphosphate) The energy used by living organisms usually originates from the sun.
Energy storage and release It takes energy to hold elements together in chemical bonds (chemical energy). When chemical bonds are broken, that energy is released. There are three phosphate groups in adenosine triphosphate (ATP). When ATP separates into ADP (adenosine diphosphate) and P, chemical energy is released. When P joins with ADP to make ATP, energy is stored.
A-P-P-P A-P-P + P + energy and A-P-P + P + energy A-P-P-P
ATP
The Role of Producers (Plants and other green organisms) Producers are the key to the food chain Producers are autotrophs. They use energy (usually light) to synthesize their own food (C 6 H 12 O 6 ) from CO 2 and H 2 0. Occurs in the Chloroplast Other (non-green) organisms obtain the stored energy by eating or ingesting green organisms. All organisms release this stored energy during the process of cellular respiration. Occurs in the Mitochondria
Photosynthesis Is performed by green plants, as well as cyanobacteria, and some chlorophyll-containing protists (ie, euglena, volvox) Converts the sun s energy into chemical form (C 6 H 12 O 6 : glucose) by combining water and carbon dioxide.
Collecting needed materials H 2 O is absorbed by the roots Plants absorb carbon dioxide and water vapour through stomata (pores surrounded by guard cells) Light is absorbed by chloroplasts which contain pigments chlorophyll (green) carotenoids (red, orange and yellow)
Many pigments may be used for attracting light, chlorophyll A is the most important in green plants. Chlorophyll is green. This means that the chlorophyll absorbs all wavelengths of light except those for green which it reflects. **Trees turn colors in fall because the green chlorophyll dies and the carotenoids are left showing.
Process of Photosynthesis There are two major types of chemical reactions that occur: Light-dependent reaction (a.k.a. light reaction) Light-independent reaction (a.k.a. dark reaction or Calvin Cycle)
Light Reactions The inner membranes of the chloroplast called thylakoid membranes have chlorophyll and protein molecules embedded in them. The thylakoids are arranged in stacks called grana. The fluid inside the chloroplast that surrounds the grana is called the stroma.
Structure
Light Reactions Cont d When photons of light enter the chloroplast they excite electrons in the proteins of the chloroplast. This excitement passes electrons along the thylakoid membranes. The passing of the electron stimulates the production of ATP (useable energy molecule) Water molecules are split releasing O 2 allowing H + to attach to the electron acceptor molecule NADP, making NADPH for later use.
Dark Reactions A.k.a: Calvin Cycle and Light-independent reaction This is where the sugars are manufactured The energy from the ATP and NADPH bind CO 2 molecules to a 5 carbon molecule (bisphosphate) making an unstable 6 carbon molecule which breaks down into two 3 Carbon molecules. Some of these 3C molecules will join to form a simple sugar (C 6 H 12 O 6 ) Others go through a series of reactions that result in a 5 carbon molecule that will be available to start the cycle again.
Dark Reaction here
The energy of the sun has now been packaged in chemical form in C 6 H 12 O 6 (Glucose) The energy from the glucose will be released in the form of ATP during Cellular Respiration which takes place in the mitochondria
Transfer to other organisms All organisms require energy, but not all organisms can make their own food. Herbivores get glucose when they eat plant matter and it gets passed along the food chain Excess glucose in animals is converted to lipid molecules and stored in fat deposits.