Chapter 7 Review Quiz

Carbohydrates

. Among the carbohydrates, vitamin C is an especially unusual compound because:

. Ribose can best be described as an:

. Forensic investigators use many types of information in order to determine what has occurred at a crime scene. In addition to being a strong acid, sulfuric acid is an oxidizing acid and has a very powerful dehydrating effect. Sulfuric acid is sometimes used by criminals to attack or disfigure victims, and persons are sometimes injured as a result of explosions of storage batteries. Exposure of skin to sulfuric acid may result in the formation of black spots; this same black color occurs when sugars are exposed to sulfuric acid. The black material is:

. Ribose and xylose are:

. The carbohydrate known as milk sugar is also known by the common name:

. An easy way to identify sucrose among other sugars is to use the Benedict's test for reducing sugars. As the first carbon of glucose and the second of fructose are locked together in the sucrose molecule, no carbon is easily oxidized, and the Benedict's test is negative. Starch contains a great deal of glucose, but gives a negative Benedicts's test because:

. Which of the following is a homopolysaccharide?

. Functions of lectins include:

. Glucose is stored in plants as amylopectin granules, and in animal tissues as glycogen granules. The two homopolysaccharides are similar in linkages, but differ in the degree of branching and in shapes of the granules. Amylopectin usually forms large, single grains, while glycogen is usually present as smaller, clustered granules resembling bunches of grapes. How does this structure of glycogen granules benefit an animal?

. The uses of vitamin C are probably not all known, but we are aware of a number of problems which occur if we lack it. Many of the Mormons who died in the winter camps during the trek westward in 1846-1848 actually suffered vitamin C deficiency. Persons who don't have sufficient vitamin C are said to suffer:

. The term glycomics refers to:

. The mucic acid test is performed by heating a sugar with nitric acid. This reaction oxidizes both ends of the sugar molecule, converting the first and last carbon to carboxylic acid groups. The product, an aldaric acid, is soluble for most sugars, but in the case of any sugar containing galactose, gritty, white, insoluble crystals of galactaric acid form. Which of the following sugars would form a white precipitate if treated with nitric acid?

. An old test for glucose in urine involved heating the urine with an alkaline solution of Cu2+. As the aldehyde group of the sugar was oxidized to an acid group, The Cu2+ ion (blue in aqueous solution) was reduced to a brick-red precipitate of Cu2O. During basic training in the military, it was not uncommon for recruits to regret their enlistments and even to attempt to avoid the day's exercise by malingering. Of course, to pretend illness, the recruit needed to have symptoms, and a few tried to feign diabetes by mixing some sugar taken from the mess hall with their urine. This attempt at avoiding duty failed because:

. Glucose crystallized from water is usually in the α-form, but if dissolved again in water, is rapidly converted into a mixture of α- and β- forms by a process called:

. Which of the following are anomeric isomers?

. Which of the following is a heteroglycan?

. Monosaccharides are classified as D-form if they:

. Much of the galactose we consume is converted to glucose and oxidized for energy. An inherited genetic disease may cause infants to be unable to convert galactose to glucose, and the resultant high levels of galactose result in formation of galactitol, a sugar alcohol. Galactitol can accumulate in some tissues and might even cause cataracts, but a principle danger of the disease is profound mental retardation. Fortunately, a special diet low in galactose allows infants to develop normally, and by the age of ten or so, they usually develop an alternative enzymatic pathway which handles the glucose safely. A characteristic symptom of this disease is elevated galactose in blood. This disease is called:

. Sugar alcohols such as sorbitol are not well absorbed from the intestine, so can be used as artificial sweeteners. Your toothpaste and sugar-free gum are probably sweetened with a sugar alcohol made by reducing the aldehyde carbon of xylose to an alcohol. The resulting compound would be named:

. Sorbitol is often used as an artificial sweetener. While sorbitol does not contribute to high blood glucose levels, it can cause diarrhea among children who consume excess quantities. Why?

. Cows and termites possess microorganisms in their digestive tracts which can hydrolyze cellulose to form molecules such as glucose which can be utilized by the hosts. In your own home, there is probably another animal which contains such microorganisms. What is it?

. How many optical isomers could an aldoheptose have?

. Formation of a hemiacetal from a monosaccharide results in a molecule which has the same molecular weight as the original monosaccharide. Formation of an acetal from two monosaccharides results in a molecule which has:

Back to top