Carb study guide NFS 3115 LSU
Terms in this set (34)
energy equilibrium occurs when one eats the same amount of energy that one expends and there is no net weight gain;
negative energy balance
negative energy balance occurs when one consumes less energy than one expends and there is a net weight loss. Depending on the situation, the weight loss may be mainly fat (weight-loss diet and exercise), or lean mass (disease).
positive energy balance
positive energy balance means that one consumes more energy than one expends and there is weight gain that occurs. If one is exercising, a good amount of the weight gain can be as lean tissue, otherwise a lot of the weight gain can be increased body fat
simple carbohydrates and include mono- and disaccharides.
polysaccharides composed entirely of glucose molecules linked together.
There are two types of starch molecules
amylose and amylopectin.
a single straight chain of glucose molecules linked together,
a multiple branched molecule.
What does Wikipedia state about the American Medical Association (AMA) and the AMAs statement on high fructose corn syrup?
essentially the effects of high fructose corn syrup are no different than those for sucrose.
According to the research of Chanmugam et al. what was responsible for the increased overweight and obesity in the United States in the late twentieth century?
increased energy and positive energy balance
optical isomers that are mirror images of each other
although they are optical isomers, are not mirror images of each other.
What is the name of the compound that is the epimer of D-glucose at carbon
What are the designations "D" and "L" based on,
D- and L-glyceraldehyde for sugars that are aldehydes (aldose sugars) and D-erythrulose for sugars that are ketones (ketose sugars).
what is mutarotation
Mutarotation is the conversion of a sugar from its beta or alpha anomer to its alpha or beta anomer, respectively, through its open-chain version of the compound.
what are anomeric carbons?
Anomeric carbons are carbons in sugars that are able to cycle between having a bond that allows the formation of a ring structure to no bond that leads to formation of the open chain structure of the sugar.
How are cellulose and starch alike
both compounds are homo-polysaccharides made up only of glucose molecules.
How are cellulose and starch Different?
cellulose is considered a non-starch polysaccharide as it is not digestible because it has beta rather than glycosidic bonds between glucose molecules.
What is alpha-dextrinase?
the enzyme that is also called isomaltose and it catalyzes the removal of a branch composed of a single glucose molecule remaining from the digestion of amylopectin.
What will textbooks not have about alpha 1-3 linkages between glucose molecule?
Recent research has demonstrated that in vitro enzymes can digest the alpha 1-3 glycosidic bond.
What was discovered in the late 1970s about complex carbohydrates that revolutionized our understanding of dietary carbohydrates?
complex carbohydrates (starch molecules) are quickly digested because the majority of starch in the diet is amylopectin. Also resistant starch was discovered
Why have pre-clinical studies with very high fructose in the diet been associated with higher body fat and blood lipids?
Rodent studies have demonstrated that diets very high in fructose bypass the regulatory steps of glycolysis in the liver via the enzyme fructokinase and become "instant trioses" in the glycolytic pathway that can be converted to acetyl-CoA, which is then used for synthesis of fatty acids.
What GLUT protein is insulin dependent and what tissues use this GLUT protein for transport of glucose into their cells?
GLUT4 is the GLUT protein that is insulin dependent and GLUT4 is found in muscle and adipose tissue cells.
What is known about the GLUT 4 mechanism?
The mechanism is that insulin signaling results in more GLUT4 in the cell membranes of muscle and liver cells.
glycemic index is
the comparison of the increase in blood glucose of a test food to a standard food such as glucose or white bread
glycemic load is
the multiplication of the decimal of the comparison times the amount of carbohydrate in the test food used for the glycemic index.
the pathway for degradation of glucose,
the pathway for the synthesis of glucose from non-carbohydrate sources.
What is the 2-carbon rule?
The 2-carbon rule means that long chain fatty acids and ketogenic amino acids cannot provide net carbons for glucose synthesis. That is because they are broken down (catabolized) only to 2 carbon units (acetate) in the form of acetyl-CoA.
What is the 3-carbon rule?
The 3-carbon rule means that glucogenic amino acids which break down to 3 (pyruvate), 4, 5, or 6 (4, 5, and 6 are Kreb's cycle intermediates) carbons provide net carbons for glucose synthesis via gluconeogenesis. This process results either directly in oxaloacetate or in conversion to oxaloacetate. Oxaloacetate can be converted to phosphoenol pyruvate in the gluconeogenesis pathway, which has 3 carbons. So all glucogenic compounds provide a half of glucose and this means it takes two glucogenic molecules to provide all 6 carbons for glucose. This is true unless a glucogenic compound is large enough to be converted to two or more 3-carbon compounds. These are net carbons.
Why cannot fatty acid carbons be used for the "net" synthesis of glucose?
Fatty acid carbons cannot be used for the "net" synthesis of glucose because acetyl-CoA cannot be converted to pyruvate or to any of the Kreb's cycle intermediates and it does not provide net carbons for glucose synthesis. So mammals cannot survive on fat alone and need protein in addition to fat with a low or no carbohydrate diet
Which amino acids are only ketogenic?
leucine and lysine.
In what phases of glucose homeostasis do most of us spend most of our time in?
Most of us spend most of our time in phases 1 and 2 of glucose homeostasis.
Do brain neural cells ever use anything else but glucose for an energy source?
The brain uses ketone bodies derived from acetyl-CoA from fatty acids and ketogenic amino acids in phases 4 and 5 of glucose homeostasis.