Exam 5: An Introduction to Carbohydrates

Dairy cattle were unknown in Thai culture until recently,and 97% percent of Thai people are lactose intolerant as adults.Which explanation for such widespread lactose intolerance is most likely correct?

Which of the following structural features is common to cellulose,chitin,and peptidoglycan?

Which of the following can vary among monosaccharides?

What is the major structural difference between starch and glycogen?

Cell walls are used by many different organisms for protection from their environment and structural support.These cell walls must obviously be insoluble in water;otherwise,they would dissolve the first time the organism got wet.Which of the following carbohydrates would you expect to be the most soluble in water?

The chemical formula for fat is C₁₂H₂₄O₃.The analogous chemical formula for carbohydrates is C₁₂ H ₂₄ O₁₂.Given the differences in their chemical formulas,why do you think that plants generally store their energy in the form of carbohydrates,but animals generally store their energy in the form of fats?

Bacteria,insects,and plants use carbohydrates to build structures.Which of the following is true of structural carbohydrates?

How do the α and β forms of glucose differ?

You isolate an organic molecule that contains C,H,O,N,and S.This molecule _____.

Compare the molecular formula of a carbohydrate (CH₂O)n with that of carbon dioxide (CO₂).What does the presence of hydrogen atoms in carbohydrates indicate?

Peptidoglycan forms sheets that stiffen the cell walls of bacteria.How is the formation of sheets possible?

If you were going to develop a new antibiotic against bacteria,you would probably need to become an expert on which of these carbohydrates?

Why do plants require sunlight?

Carbohydrates have been shown to form _____.

Enzymes that readily break starch apart cannot hydrolyze the glycosidic linkages found in cellulose.Why is this logical?

Which of the following carbohydrates contains a peptide bond?

Use the following paragraph to answer the corresponding question(s). Masatomo Kawakubo et al.reported in Science in August 2004 that the human stomach contains a natural,carbohydrate-based antibiotic that probably protects a large portion of the population from various diseases caused by the bacterium Helicobacter pylori.This bacterium has been linked to peptic ulcers,gastritis,and stomach cancer.This naturally occurring antibiotic is described by Kawakubo as having a terminal α1,4-linked N-acetylglucosamine (NAG),and it acts by inhibiting the biosynthesis of a major component of the cell wall in H.pylori.[Source: M.Kawakubo et al. ,Science 305 (2004): 1003.] -Refer to the paragraph about Kawakubo's group.Kawakubo's group created a glycoprotein with a terminal NAG (i.e. ,a protein with NAG attached to its end).Their hypothesis is that the terminal NAG and not the protein component is responsible for the damage to the cell wall in H.pylori.What would be the most appropriate control for testing this hypothesis?

Which of the following linkages would you expect to find at a branch point in glycogen or amylopectin?

A glycosidic linkage is analogous to which of the following in proteins?

Scientists believe polysaccharides played little role,if any,in chemical evolution.Which of the following is true of polysaccharides,which leads scientists to discount them as the first life-forms?