From david at forficula.co.uk Sat Sep 17 01:58:52 2005 From: david at forficula.co.uk (David) Date: Sat Sep 17 02:56:05 2005 Subject: [Grasses-science] Re: Plants and Trees - Day and Night References: Message-ID: <0aKdnbWCBpugIrbenZ2dnUVZ8qudnZ2d@pipex.net> Green plants effectively fix energy from sunlight to make carbohydrates. This is achieved through the process of photosynthesis, which is basically a two-stage process. All living organisms, including green plants, also undergo cellular respiration - the process of making energy available to the organism by breaking down molecules, such as glucose (a carbohydrate). This can be done both with or without oxygen. However, the amount of energy made available is much greater when oxygen is available and can be used. Plants do this to enable growth, repair and reproduction, as we do. It is true that, when photosynthesising, green plants release oxygen as a waste product. At the same time, they are releasing carbon dioxide from aerobic cellular respiration. It is possible for green plants to use the carbon dioxide produced in cellular respiration in photosynthesis and to use the oxygen produced in photosynthesis in cellular repiration. The point at which the amount produced and used in each of these two processes is the same is known as the compensation point. Thesefore, you might expect a plant to produce more oxygen than carbon dioxide during the day (when it is light) and the reverse when it is dark at night. I don't know the numbers involved. Hope this helps. David. "Matalog" wrote in message news:jDFTe.9267$VB1.5210@newsfe1-gui.ntli.net... >I understand that when sunlight is around trees and plants will give off > oxygen and soak up carbon dioxide (photosynthesis) - but at night is it > true > that they will give off carbon dioxide? If so, how much of each will be > released during the night and day. > > Thanks for any answers. > > P.S. At night do they take in oxygen? > > From gin-Tonik at terra.es Thu Sep 29 20:44:30 2005 From: gin-Tonik at terra.es (gin-Tonik) Date: Thu Sep 29 20:56:03 2005 Subject: [Grasses-science] La bioquimica en el espacio interestelar Message-ID: <2M0%e.4235095$I96.6437720@telenews.teleline.es> X-No-Archive: Yes Estimados usuarios żos habeis planteado como sera la sexualidad de nuestros nietos en el espacio interestelar? Creo, y por eso lo expongo, que es un tema de vital importancia para la posteridad, pues unos estudios llevados a cabo por el intelectual inter-disciplinario Juan Jose Velero, parece ser que la radiacion cosmica de fondo podria degradar el material genetico de los espermatozoides