Photosynthesis is a process used by plants and other organisms to convert light energyinto chemical energy that can later be released to fuel the organisms' activities. This chemical energy is stored in carbohydrate molecules, such as sugars, which are synthesized from carbon dioxide and water – hence the name photosynthesis, from the Greek φῶς, phōs, "light", and σύνθεσις, synthesis, "putting together".[1][2][3] In most cases, oxygen is also released as a waste product. Most plants, most algae, and cyanobacteria perform photosynthesis; such organisms are called photoautotrophs. Photosynthesis is largely responsible for producing and maintaining the oxygen content of the Earth's atmosphere, and supplies all of the organic compounds and most of the energy necessary for life on Earth.[4]
Although photosynthesis is performed differently by different species, the process always begins when energy from light is absorbed by proteins called reaction centresthat contain green chlorophyll pigments. In plants, these proteins are held inside organelles called chloroplasts, which are most abundant in leaf cells, while in bacteria they are embedded in the plasma membrane. In these light-dependent reactions, some energy is used to strip electrons from suitable substances, such as water, producing oxygen gas. The hydrogen freed by the splitting of water is used in the creation of two further compounds that serve as short-term stores of energy, enabling its transfer to drive other reactions: these compounds are reduced nicotinamide adenine dinucleotide phosphate(NADPH) and adenosine triphosphate (ATP), the "energy currency" of cells.
In plants, algae and cyanobacteria, long-term energy storage in the form of sugars is produced by a subsequent sequence of light-independent reactions called the Calvin cycle; some bacteria use different mechanisms, such as the reverse Krebs cycle, to achieve the same end. In the Calvin cycle, atmospheric carbon dioxide is incorporatedinto already existing organic carbon compounds, such as ribulose bisphosphate(RuBP).[5] Using the ATP and NADPH produced by the light-dependent reactions, the resulting compounds are then reducedand removed to form further carbohydrates, such as glucose.
The Suns own weight keeps itself together and keeps its size and shape. all things have gravity. in this case, the sun keeps it shape with balancing its gravity with the pressure.
.D. two daughter cells with twice the amount of DNA.
Mitosis is a multiplication division with the daughter cells having twice(diploid) the amount of DNA present in the parent cells that is 2n, The Chromosomes number doubles in the daughter cells , and therefore the DNA also doubles with each successful generation in the daughter cells. It is this ability to multiply the genetic components that makes Mitosis to be called multiplication division.
The parents and daughter cells are exactly similar.
Each daughter cell with its double genetic composition can also pass on to its own subsequent generation the genetic composition since its DNA and chromosomes . Thus enough amount can be passed to its own daughter cells too, which explains the need for double DNA inherited from the parents