Origin of photosynthesis
Examples from the Web for photosynthesis
Contemporary Examples of photosynthesis
Nevertheless, it was required, and at least it was more fun than studying algebra or photosynthesis.The Financial Case for Dodgeball: Why America Needs Gym Class
April 28, 2014
Re-solarizing the food chain should be our goal in every way—taking advantage of the everyday miracle that is photosynthesis.It’s the End of the World Unless We All Start Cooking
April 23, 2013
Historical Examples of photosynthesis
Now, the red rays of the spectrum are the ones which are most efficient for photosynthesis.The Chemistry of Plant Life
Roscoe Wilfred Thatcher
On the other hand, their ancestors, the green or yellow mastigota, form new plasm by photosynthesis like true cells.
There the miracle of life consists merely of the chemical process of plasmodomism by photosynthesis.
Growing plants kept the air in their greenhouse fresh and breathable by photosynthesis.Asteroid of Fear
Raymond Zinke Gallun
These two are the materials for the reverse process in photosynthesis.
- (in plants) the synthesis of organic compounds from carbon dioxide and water (with the release of oxygen) using light energy absorbed by chlorophyll
- the corresponding process in certain bacteria
[T]he body of the work has been rendered into English with fidelity, the only change of moment being the substitution of the word "photosynthesis" for that of "assimilation." This change follows from a suggestion by Dr. Barnes, made a year ago before the American Association at Madison, who clearly pointed out the need of a distinctive term for the synthetical process in plants, brought about by protoplasm in the presence of chlorophyll and light. He proposed the word "photosyntax," which met with favor. In the discussion Professor MacMillan suggested the word "photosynthesis," as etymologically more satisfactory and accurate, a claim which Dr. Barnes showed could not be maintained. The suggestion of Dr. Barnes not only received tacit acceptance by the botanists of the association, but was practically approved by the Madison Congress in the course of a discussion upon this point. ["The Botanical Gazette," vol. XIX, 1894]
- The process in green plants and certain other organisms by which carbohydrates are synthesized from carbon dioxide and water using light as an energy source.
- The process by which green plants, algae, diatoms, and certain forms of bacteria make carbohydrates from carbon dioxide and water in the presence of chlorophyll, using energy captured from sunlight by chlorophyll, and releasing excess oxygen as a byproduct. In plants and algae, photosynthesis takes place in organelles called chloroplasts. Photosynthesis is usually viewed as a two-step process. First, in the light reactions, the energy-providing molecule ATP is synthesized using light energy absorbed by chlorophyll and accessory pigments such as carotenoids and phycobilins, and water is broken apart into oxygen and a hydrogen ion, with the electron of the hydrogen transferred to another energy molecule, NADPH. The ATP and NADPH molecules power the second part of photosynthesis by the transfer of electrons. In these light-independent or dark reactions, carbon is broken away from carbon dioxide and combined with hydrogen via the Calvin cycle to create carbohydrates. Some of the carbohydrates, the sugars, can then be transported around the organism for immediate use; others, the starches, can be stored for later use. Compare chemosynthesis. See Note at transpiration.
A Closer Look: Almost all life on Earth depends on food made by organisms that can perform photosynthesis, such as green plants, algae, and cyanobacteria. These organisms make carbohydrates from carbon dioxide and water using light energy from the Sun. They capture this energy with various pigments which absorb different wavelengths of light. The most important pigment, chlorophyll a, captures mainly blue and red light frequencies, but reflects green light. In plants, the other pigments are chlorophyll b and carotenoids. The carotenoids are usually masked by the green color of chlorophyll, but in temperate environments they can be seen as the bright reds and yellows of autumn after the chlorophyll in the leaves has broken down. The energy gathered by these pigments is passed to chlorophyll a. During the light reactions, the plant uses this energy to break water molecules into oxygen (O2), hydrogen ions, and electrons. The light reactions produce more oxygen than is needed for cellular respiration, so it is released as waste. All of the oxygen in the Earth's atmosphere today was produced as waste by photosynthetic organisms, especially cyanobacteria, which have been producing oxygen for some three billion years, since their first appearance in the Precambrian Eon. During the dark reactions, the plant uses hydrogen ions and the electrons to make carbon dioxide into carbohydrates. Within the leaf of a green plant, photosynthesis takes place in chlorophyll-containing chloroplasts in the columnlike cells of the palisade layer and in the cells of the spongy parenchyma. The cells obtain carbon dioxide from air that enters the leaf through holes called stomata, which also allow excess oxygen to escape. Water from the roots is brought to the leaf by the vascular tissues called xylem, while the carbohydrates made by the leaf are distributed to the rest of the plant by the vascular tissue called phloem.