Carbohydrates Flashcards
Name two functional groups found in the straight-chain form of glucose.
carbonyl and hydroxyl
Which of the monosaccharides are isomers?
glucose, fructose and galactose
What are the differences between a ketotriose and an
aldopentose? Provide an example of each.
Ketotriose - dihydroxyacetone - has three carbons and a carbonyl ketone group at the second carbon.
Aldopentose - ribulose - has five carbons and a carbonyl group at one terminal end.
How does the structure of a monosaccharide change
when it is placed in an aqueous solution?
The structure of a monosaccharide changes from linear to rings.
(a) Why are glycogen and starch called storage polysaccharides?
(b) Why are cellulose and chitin called structural polysaccharides?
a) Glycogen and starch have a lot of energy stored in them that is used for processes that need energy.
b) Cellulose and chitin are found in the walls, shells or skeletons of organisms because their chemical structure is rigid and their intermolecular bonds are very strong which provides structural support to cells.
Distinguish between the glycosidic bonds in amylose and cellulose.
Amylose has unbranched alpha glycosidic bonds that are joined at carbon 1 and 4. This glycosidic bond is weak in comparison to the glycosidic bond in cellulose. The beta glycosidic bonds in cellulose results in some of the glucose molecules being inversed which creates hydrogen bonds between the chain of glucose monomers. Due to the strength of hydrogen bonds, cellulose has a more rigid and tougher structure than amylose.
Why can humans not obtain energy by eating grass?
The human digestive system does not contain the bacteria required to break down or digest cellulose in the grass and so it will pass through the system without releasing energy (its bonds are still intact).
What are some practical uses for discarded crab and lobster shells?
Crab and lobster shells can be used as biodegradable dissolving stitches in hospitals for open wounds or contact lenses.
What is “dietary roughage” and why is it good for you?
Dietary roughage comes from the cellulose or fiber in plants that acts as a cleaning agent for intestines because it is not digested, it remains whole and ‘scrapes’ or cleans the inside of our intestines, especially the large intestine not allowing any feces or deposits to be left in the intestine as unmoved waste.
