12. Which of these agents will denature a protein? A. Temperature B. Heavy metals C. Detergents D. Organic Solvents E. Mechanical Stress F. All of the above 13- Which of these statements are FALSE with respect to the chemical properties of monosaccharides? A- Because the cyclic and linear forms of aldoses and ketoses interconvert, these sugars undergo reactions typical of aldehydes and ketones. B. The aldehyde group of an aldose can be oxidized to a carboxylic acid. C. The carbonyl group in both an aldose and ketose can be reduced to give a hydroxyl group. D- all of the above E- none of the above 14- Which of these carbohydrates are NOT reducing sugars? A- amylase B- glucose C- galactose D- fructose E- sucrose F-neither A or E 15. Which of these statements is false? A. All disaccharides are reducing sugars B. Most disaccharides are reducing sugars, except sucrose C. Sucrose does not react with Fehling's reagent because the anomeric carbon of glucose is involved in the glucose- fructose bond and hence is not free to form an aldehyde in solution that can be oxidized. D.Sucrose does not react with Fehling's reagent because since it no longer has an anomeric carbon with a free potential aldehyde or ketone group, it can no longer exhibit reducing properties. E. none of the above 16-Which of the following is FALSE about the reaction of fructose and Fehling's solution? A. Fructose gives a positive test with Fehling's solution, because fructose is converted to glucose and mannose under alkaline conditions. B. Fructose gives a positive test with Fehling's solution, because a keto-enol tautomerism occurs to allow this to occur. C.Fructose gives a positive test with Fehling's solution, because the ketose, fructose is isomerized into an aldose by tautomerisation via an enediol. D. all of the above E. none of the above
