What is the difference between a monosaccharide, an oligosacchaide, and a polysaccharide?
answer
The number of monomers in the molecule.
question
What are the three ways monosaccharides differ from one another?
answer
1) The location of their carbonyl group
2) The number of carbon atoms they contain and
3) The orientations of their hydroxyl groups
question
What type of bond is formed between two sugars in a disaccharide?
answer
Glycosidic linkage.
question
What holds cellulose molecules together in bundles large enough to form fibers?
answer
Hydrogen bonds.
question
What are the primary functions of carbohydrates in cells?
answer
Energy storage, cell identity, structure, and building blocks for synthesis.
question
What is responsible for the difference in potential energy between carbohydrates and carbon dioxide?
answer
The electrons in the C=O bonds of carbon dioxide molecules are held tightly by the highly electronegative oxygen atoms, so they have low potential energy. The electrons in the C-C bonds and C-H bonds of carbohydrates are shared equally, so they have much higher potential energy.
question
Which of the differences listed here could be found in the same monosaccharide?
A) Different orientation of a hydroxyl in in the linier form
B) Different number of carbons
C) Different orientation of hydroxyl in the ring form
D) Different position of the carbonyl group in the linier form
answer
Different orientation of hydroxyl in the ring form.
question
What would most likely occur if the galactose in lactose water were replaces with glucose?
answer
It would not be designed by human infants or adults. Lactose is a disaccharide formed from beta-1,4-glycosidic linkage, so if two glucose molecules were linked with this bond, they would resemble units of cellulose and not be digested by human infants or adults.
question
Explain how the structure of carbohydrates supports their function in displaying the identity of a cell.
answer
Carbohydrates are ideal for displaying the identity of the cell because they are so diverse structurally. This diversity enables them to serve as very specific identity tags for cells.
question
What is the difference between linking glucose molecules with alpha-1,4-glycosidic linkages versus beta-1,4-glycosidic linkages? What are the consequences?
answer
When you compare the glucose monomers in an alpha-1,4-glycosidic linkage varies in beta-1,4-glyosidic linkages, the linkages are located n the opposite sides of the plane of the glucose rings, and the glucose monomers are linked in the same orientation versus having every other glucose flipped in orientation. Beta-1,4-glycosidic linkages are much more likely to form linier fibers and sheets, so they resist degradation.
question
Give the three reasons why researchers have concluded that polysaccharides were unlikely to play a large role in the origin of life.
answer
Because (1) no mechanism is known for the prebiotic polymerization of sugars; (2) no catalytic carbohydrates have been discovered that can preform polymerization reactions; and (3) sugar residues in polymerization are not capable of complementary base paring.
question
Compare and contrast the structures and functions of starch and glycogen. How are these molecules similar? How are they different?
answer
Starch and glycogen both consist of glucose monomers joined by alpha-1,-glycosidic linkages, and both function as storage carbohydrates. Starch is a mixture of unbranched and branched polysaccharides- called amylose and amylopectin, respectively. All glycogen polysaccharides are branched.
question
A weight-loss program for humans that emphasized mineral consumption of carbohydrates was popular in some countries in the early 2000's. What was the logic behind this diet? (Note: the diet plan caused controversy and not endorsed by some physicians and researchers.)
answer
Carbohydrates are energy-storage molecules, so minimizing their consumption may reduce total energy intake. Lack of available carbohydrates also force the body to use fats or energy, reducing the amount of fat that is stored.
question
Galactosemia is a potentially fatal disease that occurs in humans who lack enzymes that converts galactose to glucose. To treat this disease, physicians exclude the monosaccharide galactose from the diet. Which of the following would you also predict to be excluded from the diet?
A) Maltose
B) Starch
C) Mannose
D) Lactose
answer
Lactose. Lactose is a disaccharide glucose and galactose, which can be cleaved in enzymes expressed in the human gut to release galactose.
question
If you hold a salty cracker in your mouth for long enough, it will begin to taste sweet. What is responsible for this change in taste?
answer
Amylase breaks down the starch in the cracker into glucose monomers, which stimulates sweet receptors in your tongue.
question
Lysosome, an enzyme found in human saliva, tears, and other secretions, catalyzes the hydrolysis of the beta-1,4-glycosidic linkages in peptidoglycan. Predict the effect of this enzyme on bacteria, and explain the role its activity plays n human health.
answer
When bacteria contact lysozyme, the peptidoglycan in their cell walls begin to degrade, leading to the death of bacteria. Lysozyme therefore helps protect humans against bacterial infections.
Haven't found what you need?
Search for quizzes and test answers now
Quizzes.studymoose.com uses cookies. By continuing you agree to our cookie policy
