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Index of Subjects ------=_Part_8472_20836176.1200239901509 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline On 12/01/2008, David & Alison Webster <dwebster@glinx.com> wrote: > > Hi Randy & All, Jan 12, 2008 > While it is true that starch is a common storage carbohydrate, > soluble sugars are the building blocks and are present especially when > starches are being formed or used. True, but the dominant soluble sugars would likely be the simple ones such as glucose (the building block of starch) and fructose. With respect to sucrose, Bonner and Varner (Plant Biochemistry, > 1965, 1054 p.) observe that "Sucrose... is by far the most commonly > found disaccharide in nature, its distribution being universal among > photosynthetic plants." No question. But "most common" is a relative term - the Common Nighthawk is the most common goatsucker in the province, but that doesn't mean it's common. Hydrolysis of sucrose is spontaneous in the presence of weak acid I didn't know that. I always assumed the enzyme sucrase did that job exclusively. Does the process also work in the presence of strong acids, as found in the stomachs (or stomach-equivalents) of animals? so, although the process would take time, the formation of > monosaccharides from sucrose would not consume metabolic energy. Except of course for the creation and likely the secretion of the acid. I dare > say birds and ancestors, over evolutionary time, would have encountered > sucrose and common salt on a more regular basis than they would have > encountered suet. It depends which birds of course. Carnivorous birds (including insectivores) would have rarely encountered sucrose, unless it was in part of the digestive system of the prey (mouth to small intestine), as part of the prey's last meal. Suet, which is simply fat, would be encountered by many species (albeit not encountered by them in cages or logs). I assume that there is some difference in the composition of fats in plants and animals (biochemistry was never a strong point of mine), though metabolically, there are a lot more similarities than differences. Randy > _________________________________ > RF Lauff > Way in the boonies of > Antigonish County, NS. ------=_Part_8472_20836176.1200239901509 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline <br><br> <div><span class="gmail_quote">On 12/01/2008, <b class="gmail_sendername">David & Alison Webster</b> <dwebster@glinx.com> wrote:</span> <blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">Hi Randy & All, Jan 12, 2008<br> While it is true that starch is a common storage carbohydrate, <br>soluble sugars are the building blocks and are present especially when<br>starches are being formed or used.</blockquote> <div> </div> <div>True, but the dominant soluble sugars would likely be the simple ones such as glucose (the building block of starch) and fructose.</div> <div> </div><br> <blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid"> With respect to sucrose, Bonner and Varner (Plant Biochemistry,<br>1965, 1054 p.) observe that "Sucrose... is by far the most commonly <br>found disaccharide in nature, its distribution being universal among<br>photosynthetic plants."</blockquote> <div> </div> <div>No question. But "most common" is a relative term - the Common Nighthawk is the most common goatsucker in the province, but that doesn't mean it's common.</div><br> <blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid"> Hydrolysis of sucrose is spontaneous in the presence of weak acid</blockquote> <div> </div> <div>I didn't know that. I always assumed the enzyme sucrase did that job exclusively. Does the process also work in the presence of strong acids, as found in the stomachs (or stomach-equivalents) of animals?</div><br> <blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">so, although the process would take time, the formation of<br>monosaccharides from sucrose would not consume metabolic energy. </blockquote> <div> </div> <div>Except of course for the creation and likely the secretion of the acid.</div><br> <blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">I dare<br>say birds and ancestors, over evolutionary time, would have encountered<br>sucrose and common salt on a more regular basis than they would have <br>encountered suet.</blockquote> <div> </div> <div>It depends which birds of course. Carnivorous birds (including insectivores) would have rarely encountered sucrose, unless it was in part of the digestive system of the prey (mouth to small intestine), as part of the prey's last meal. Suet, which is simply fat, would be encountered by many species (albeit not encountered by them in cages or logs). I assume that there is some difference in the composition of fats in plants and animals (biochemistry was never a strong point of mine), though metabolically, there are a lot more similarities than differences. </div><br> <blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">Randy<br>_________________________________<br>RF Lauff<br>Way in the boonies of<br>Antigonish County, NS. </blockquote></div> ------=_Part_8472_20836176.1200239901509--
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