Glucose molecules are the immediate product of photosynthesis. They represent the transfer of light energy into a form of molecular energy holding carbon, oxygen and hydrogen atoms together, available for release during cellular respiration in the mitochondria as ATP. This energy is useful to drive further metabolism resulting in construction of more plant structures.
Glucose, and atom components, does more than only supplying energy for plant growth. Cellulose and its chemical relatives such as hemicellulose, lignin and pectin are mostly long chains of glucose molecules. Cellulose may be composed of 2000 glucose molecules held together in tight chemical bonds. These become the main component of cell walls, giving strength to plant structure. These chemical bonds are strong, allowing specific enzymes or considerable energy, such as from fire, to break up the bonds into its components. Humans cannot directly break down the cellulose to retrieve the energy locked up in the glucose components. It is the enzymes in certain microbes such as bacteria in animal guts. Many fungi thrive by feeding on the complex cell wall components of living or dead plants. Evolution favored construction of complex carbohydrate molecules to expose more tissue to light with plant growth and it also favored the production of enzymes in bacterial and fungi to capture the energy locked up in these structures.
Carbon, hydrogen and oxygen from the glucose molecules also become major components of proteins used as part of plant structure and as enzymes. Actual structure of these proteins is guided by the nucleic acid pattern in DNA. This is ‘read’ when a gene is turned on as it is duplicated into RNA, moved to ribosomes resulting in the hooking amino acids in a specific pattern. Amino acids are composed of nitrogen, carbon, hydrogen and oxygen atoms. The order of specific amino acids in the protein affect its enzymatic effect on construction of other cellular parts, including cellulose.
Photosynthesis resulted in energy transfer from light into glucose but also allowed a series of construction processes to make a corn plant.
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About Corn Journal
The purpose of this blog is to share perspectives of the biology of corn, its seed and diseases in a mix of technical and not so technical terms with all who are interested in this major crop. With more technical references to any of the topics easily available on the web with a search of key words, the blog will rarely cite references but will attempt to be accurate. Comments are welcome but will be screened before publishing. Comments and questions directed to the author by emails are encouraged.