Plant biosynthesis is the collection of natural processes that plants undergo to convert inorganic mineral elements such as potassium and nitrogen in soil along with elements in water and air into nutrients, using energy derived initially from sunlight. These processes are broken down into three basic categories for plants, which include photosynthesis, respiration, and chemical synthesis. Like animals and other living organisms such as bacteria, plants rely on the exchange of oxygen and carbon dioxide in the atmosphere to survive. They also synthesize and break down many of the same compounds in plant biosynthesis that animals do, including amino acids, lipids, and carbohydrates.
Understanding the key processes of photosynthesis and cellular respiration in plants is the first step towards understanding biosynthesis in plants overall. Photosynthesis is a process that takes the energy from visible light in specific wavelengths and stores it in sugar molecules in plants through the use of choloroplasts. Chloroplasts are small organelles within plant cells that contain chlorophyll, a green compound that gives plants their color and is used in synthesizing carbohydrates such as sugar.
Plant biosynthesis uses three different types of pigments to maximize its absorption of light. The pigment chlorophyll a absorbs light most strongly around the 430 nanometer wavelength, which is largely blue in color, and chlorophyll b absorbs light around a 470 nanometer wavelength which is true green. Another pigment produced by some plants is carotenoid, which absorbs light in the yellow to orange range of the visible spectrum from 500 nanometer wavelengths or greater.
Plant respiration is also a key feature of how plants function to take in carbon dioxide and remove oxygen as a waste gas, but they do not breathe these gasses in and out as animals do. The process of respiration in plant biosynthesis involves plants allowing air to diffuse into their external cellular structure, where these combined gasses are then transported by water to internal cellular membranes. The energy for respiration comes from stored glucose created during photosynthesis. Plants break down glucose for energy just as animals do, and are rather efficient at it with a net energy gain of 22% to 38%. This is superior to many forms of modern human technology such as the automobile, which is less than 25% efficient at converting gasoline to energy for motion.
The energy production process in plant biosynthesis is based on the same chemical reaction that all animals use to generate energy. Plants utilize molecules of adenosine triphosphate (ATP) to both store and release energy as ATP is both built up chemically and broken down by mitochondria in plant cells. The difference between plants and animals in this process is that the waste products of energy production for plants are also glucose, oxygen, and water, all of which are essential compounds that animals rely on for survival.
Plant metabolism of other chemicals can be extremely complex, and science is intricately involved in studying biosynthesis pathways in plants due to the numerous types of useful organic compounds that plants produce. Plant enzymes are known as of 2011 to synthesize over 200,000 different types of chemicals, many of which can be harvested for use in food products and medicines. Most commercially useful compounds produced by plant biosynthesis cannot yet be made by artificial means in laboratory settings, however, so the plants themselves must be grown to harvest the chemicals. Research into plant biosynthesis as of 2011 focuses on the actual methodology that a plant uses to create a compound, and, once this is thoroughly understood, cell cultures of the plant can be grown in large numbers to produce the chemical commercially.