The Basics of Photosynthesis By: Candace Thibodeaux
What is photosynthesis & How was it found? n In the process of photosynthesis, plants convert the energy of sunlight into the energy in the chemical bonds of carbohydrates- sugars and starches. n For many years, gardeners wondered how a few seedlings could develop into a large tree. The mass of seedlings are only a few grams, where as the mass of a tree is several tons. Dutch physician Jan Van Helmont devised an experiment. He concluded that the mass grew from the water, because that was the only thing he had added to the pot. This was just one of the things needed for photosynthesis to occur.
What makes photosynthesis complete? n Helmont did not realize that carbon dioxide in the air also plays a major role in the contribution of mass growth. The carbon in carbon dioxide is what is used to make carbohydrates in photosynthesis. n Later on, scientist Joseph Priestly performed an experiment that would give rise to why oxygen is released in photosynthesis, and why sunlight is needed for it to photosynthesize. Priestly placed a candle in a jar along with a mint plant. He then realized that the candle could only stay lit when the mint plan was present. This would mean that the plant was releasing oxygen. We then realized that without light, plants cannot photosynthesize.
Why is Photosynthesis important? n Through the experiments formed, it was realized that in the presence of light, plants transform carbon dioxide and water into carbohydrates and release oxygen. Plants that are able to use a source of energy, such as sunlight, to provide food directly from simple inorganic molecules are known as autotrophs. This is made possible through photosynthesis. n Thus the equation for photosynthesis is:
Light Absorption & Light Energy n The actual process of photosynthesis begins when light is absorbed by pigments in the plant cell. The principal pigment in plants is chlorophyll which gives the plant its green color. n Another way in which light energy is trapped in chemical form involves adinosine triphospate or ATP. During photosynthesis, green plants produce ATP, which is the energy storing compound used by every living cell. The energy is released by means of breaking the phosphate bonds which make up the ATP cycle. The energy is used in almost all cellular activities.
Self-Evaluation Questions n Through this multimedia presentation, you should have become more aware of the basics of photosynthesis. n By understanding photosynthesis, it gives you a clearer understanding of how plants are able to survive an develop mass in a more productive way. n 1. In the process of photosynthesis, plants convert the energy of sunlight into what? n 2. When Helmont devised an experiment, he concluded that the mass grew from the_____, which was the only thing he had added to the soil. n 3. What scientist gave rise to the explanation of plants giving off oxygen, and the reason sunlight is needed in order for plants to photosynthesize? n 4. Fill in the missing part of the equation for photosynthesis--Carbon dioxide + water yields what? (two things) n 5. What do you call plants that obtain their nutrients in organic molecules through photosynthesis? n If you have any difficulty in answering these question, just refer back to the previous slides, and the answers are in the information given.