Chapter 5 Bio 151
the molecular formula for glucose is C6H12O6. what would be the molecular formula for a molecule made by linking 3 glucose molecules together by dehydration reactions?
C18H32O16
the molecular formula for glucose is C6H12O6. what would be the molecular formula for a polymer made by linking ten glucose molecules together by dehydration reactions?
C60H102O51
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?
Carbohydrates are more reduced than carbon dioxide.
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?
Evolutionarily, producing an enzyme to break down a sugar that will never be encountered is wasteful.
Peptidoglycan forms sheets that stiffen the cell walls of bacteria. How is the formation of sheets possible?
Individual strands are joined by peptide bonds, a type of covalent bond.
Bacteria, insects, and plants use carbohydrates to build structures. Which of the following is true of structural carbohydrates?
Structural carbohydrates are long strands of monomers; the strands are chemically linked together to form a network.
Why do plants require sunlight?
Sunlight energy can be used by plants to reduce the carbon atoms in carbon dioxide.
Enzymes that readily break starch apart cannot hydrolyze the glycosidic linkages found in cellulose. Why is this logical?
The geometry of the bonds is different, and the shapes of enzyme active sites are highly specific.
How do the a and B forms of glucose differ?
Their ring structures differ in the location of a hydroxyl group.
which of the following structural features is common to cellulose, chitin, and peptidoglycan?
They can all form bonds between polymer chains that create parallel strands.
The molecules shown in the figure is —-?
a hexose
cellulose is—-?
a major structural component of plant cell walls
which of the following would you expect to have the most free energy per gram?
a molecule with carbon and hydrogen atoms only
Diffusion
a passive process in which molecules move from a region of higher concentration to a region of lower concentration
which of the following linkages would you expect to find at a branch point in glycogen or amylopectin?
alpha 1,6 glycosidic linkage
starch and cellulose
are polymers of glucose
Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified?
as a disaccharide
which of the following categories includes all others in the list?
carbohydrate
which of the following best explains why carbs are advertised as a quick energy boost?
carbs are reduced molecules that have high-energy electrons
how do carbs contain and/or display information for cells?
carbs contain and display info at the cell surface
what does the term insoluble fiber refer to on food packages?
cellulose
Which polysaccharide is an important component in the structure of many animals and fungi?
chitin
which of the following polymers contain nitrogen?
chitin
you can isolate an organic molecule that contains C,H,O,N and S. this molecule—-
could be a glycoprotein
Chitin is a major component of the _____.
exoskeleton of insects
which of the following is not a polymer?
glucose
which of these best reflects the following relationship; monosaccharide vs polysaccharide?
glucose vs. glycogen
the enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are in alpha form. which of the following could amylase break down?
glycogen, starch, and amylopectin
refer to the paragraph about ... what would be the most appropriate control for testing this hypothesis?
grow H pylori in a test tube with a glycoprotein that has its terminal NAG removed
Humans can digest starch but not cellulose because
humans have enzymes that can hydrolyze the α glycosidic linkages of starch but not the β glycosidic linkages of cellulose.
all of the following are polysaccharides except —-?
lactose
what role, if any, did polysaccharides playing chemical evolution?
litte, if any
If 2 molecules of the general type shown in Figure 5.1 were linked together, carbon 1 of one molecule to carbon 4 of the other, the single molecule that would result would be
maltose
a primary function of carbs attached to the glycoproteins of animal cell membranes is to —-.
mediate cell-cell recognition
A molecule with the chemical formula C6H12O6 is probably a
monosaccharide
A glycosidic linkage is analogous to which of the following in proteins?
peptide bond
If you were going to develop a new antibiotic against bacteria, you would probably need to become an expert on which of these carbohydrates?
peptidoglycan
which of the following molecules contains at least one peptide bond?
peptidoglycan
cell walls are used by many different organisms for protection from their environment and structural support. which carb would be most solvable in water?
starch
the enzyme amylase can break glycosidic linkages between monomers only if the monomers are in the alpha form. which of the following could amylase break down?
starch
What is the major structural difference between starch and glycogen?
the amount of branching that occurs in the molecule
Which of the following can vary among monosaccharides?
the number of carbon atoms
what is the difference between an aldose sugar and a ketose sugar?
the position of the carbonyl group
which of the following do starch and cellulose have in common?
the size of their monosaccharide subunits
Glucose (C6H12O6) has a single carbonyl group in its linear form. How many hydroxyl groups would you expect glucose to have?
5
