The question states that the molecule has the same structure as glucose, except at one stereogenic center. Recall that epimers are structural isomers that differ at one stereogenic center; therefore, glucose and the compound are epimers. The epimers of glucose include galactose and mannose. All three molecules have a molecular formula of .

Recall that aldoses are carbohydrates that have an aldehyde group at one of the carbons. Glucose and all of its epimers have an aldehyde group at the first carbon; therefore, this compound is an aldose.

Fructose is a ketose that has a ketone group in the second carbon. Recall that aldehydes and ketones have carbonyl groups; therefore, they are not considered stereogenic centers (to be a stereogenic center you need to have four distinct functional groups on a carbon). Since fructose differs from glucose at a non-stereogenic center, this molecule cannot be fructose. Note that fructose also has a different molecular formula (). 

Only 1% of all sugars that have five or more carbons are found in an open chain, thus any sugar that has five or more carbons will be most likely found in its cyclic form. Of the four choices a triose is the only one that has less that five carbons (it has three) the others have 5 (pentose), 6 (hexose), and 7 (heptose).

Given no other information about how many carbons are in the chain, any monosaccharide with a carbonyl group on a carbon between two others and not at the terminal carbon of the chain is called a ketose. Aldoses are when the carbonyl group is at the end of the chain. Ribose and aldohexose are incorrect because 1) ribose is too specific, we do not know anything about the structure and ribose indicates a specific monosaccharide, and 2) aldohexose has an aldehyde group, not a ketone group. 

A furanose is defined as a cyclical sugar structure with a five-membered ring. By contrast, a pyranose is a cyclical sugar structure with a six-membered ring.

Three common simple sugars are: glucose, fructose, and galactose. Combining these simple sugars leads to the formation of more complex sugar molecules. Glucose and fructose make sucrose. Glucose and galactose make lactose. Two glucose molecules make maltose. 

A pyranose is a carbohydrate that includes a ring. It is not an open-chain carbohydrate. Additionally, this term is reserved for six-membered, not five-membered carbohydrate ring structures. A sugar which contains a five-membered ring as part of its cyclic structure is called a furanose.

As carbohydrates are broken down, they are oxidized to carbon dioxide . This process, cellular respiration, begins during glycolysis. Reduction is the opposite of oxidation, and would indicate a loss of oxygen. Elimination refers to the removal of a functional group, which does not occur during this process. In substitution, one functional group is replaced with another, which also does not accurately describe this process. Finally, proteolysis refers to the breakdown of proteins, not carbohydrates.

Most mammals are unable to digest beta glycosidic bonds, such as the bonds in cellobiose and lactose. Maltose and sucrose both are connected via alpha glycosidic bonds, and can be digested by mammals.

Note: Most mammals are unable to digest lactose after infancy. It is only through a genetic mutation that many humans now are able to ingest lactose well into adulthood.

This is a fact question. A lactone is a cyclic ester, which is a ring of two or more carbon atoms and one oxygen atom with a ketone at one of the carbons adjacent to the other oxygen. Lactones are usually formed via a reaction of a carboxylic acid with a hydroxyl group or halogen atom present in the same molecule.

Maltose is a disaccharide formed from two glucose molecules. Mammals use the enzyme maltase to digest maltose. Lactose is a disaccharide formed from one glucose and one galactose molecule. Mammals use the enzyme lactase to digest lactose. Sucrose is a disaccharide formed from one glucose and one fructose molecule. Mammals use the enzyme sucrase to digest sucrose. Mammals cannot digest cellulose because they do not have the necessary enzymes to do so in their digestive tracts.