45 terms

Chapter 5: The Structure and Function of Large Biological Molecules

Mastering Biology
Which of the following is not a polymer?
What is the chemical mechanism by which cells make polymers from monomers?
dehydration reactions
How many molecules of water are needed to completely hydrolyze a polymer that is 11 monomers long?
Which of the following best summarizes the relationship between dehydration reactions and hydrolysis?
Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers; and macromolecular synthesis occurs through the removal of water and digestion occurs through the addition of water.
The molecular formula for glucose is C6H12O6. What would be the molecular formula for a molecule made by linking three glucose molecules together by dehydration reactions?
On food packages, to what does the term "insoluble fiber" refer?
The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are the form. Which of the following could amylase break down?
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 is true of both starch and cellulose?
They are both polymers of glucose
Humans can digest starch but not cellulose because
humans have enzymes that can hydrolyze the alpha () glycosidic linkages of starch but not the beta () glycosidic linkages of cellulose.
All of the following statements concerning saturated fats are true except
They have multiple double bonds in the carbon chains of their fatty acids.
A molecule with the formula C18H36O2 is probably a
fatty acid
Which of the following statements is false for the class of biological molecules known as lipids?
They are soluble in water
What is a triacylglycerol?
a lipid made with three fatty acids and glycerol
Which of the following is true regarding saturated fatty acids?
They are the principal molecules in lard and butter.
Large organic molecules are usually assembled by polymerization of a few kinds of simple subunits. Which of the following is an exception to this statement?
a steroid
The hydrogenation of vegetable oil results in which of the following?
saturated fats and unsaturated fats with trans double bonds, an increased contribution of artherosclerosis, and the oil (fat) being a solid at room temperature.
Why are human sex hormones considered to be lipids?
They are steroids, which are not soluble in water.
Which of the following is a diverse group of hydrophobic molecules?
All of the following contain amino acids except
The bonding of two amino acid molecules to form a larger molecule requires
the release of a water molecule.
There are 20 different amino acids. What makes one amino acid different from another?
different side chains (R groups) attached to an alpha () carbon
The bonding of two amino acid molecules to form a larger molecule requires which of the following?
removal of a water molecule
Polysaccharides, lipids, and proteins are similar in that they
are synthesized by dehydration reactions.
Dehydration reactions are used in forming which of the following compounds?
triacylglycerides, polysaccharides, and proteins
How many different kinds of polypeptides, each composed of 12 amino acids, could be synthesized using the 20 common amino acids?
20 ^12
Which bonds are created during the formation of the primary structure of a protein?
peptide bonds
What maintains the secondary structure of a protein?
hydrogen bonds
Which type of interaction stabilizes the alpha () helix and the beta () pleated sheet structures of proteins?
hydrogen bonds
The helix and the pleated sheet are both common polypeptide forms found in which level of protein structure?
A strong covalent bond between amino acids that functions in maintaining a polypeptide's specific three-dimensional shape is a (an)
disulfide bond
At which level of protein structure are interactions between the side chains (R groups) most important?
The R group or side chain of the amino acid serine is -CH2-OH. The R group or side chain of the amino acid alanine is -CH3. Where would you expect to find these amino acids in a globular protein in aqueous solution?
Alanine would be in the interior, and serine would be on the exterior of the globular protein.
The function of each protein is a consequence of its specific shape. What is the term used for a change in a protein's three-dimensional shape or conformation due to disruption of hydrogen bonds, disulfide bridges, or ionic bonds?
What is the term used for a protein molecule that assists in the proper folding of other proteins?
Which of the following is an example of hydrolysis?
the reaction of a fat, forming glycerol and fatty acids with the utilization of water
The element nitrogen is present in all of the following except
Enzymes are
Which of the following statements about the 5' end of a polynucleotide strand of DNA is correct?
The 5' end has a phosphate group attached to the number 5 carbon of deoxyribose.
Which of the following best describes the flow of information in eukaryotic cells?
DNA -> RNA -> proteins
Which of the following descriptions best fits the class of molecules known as nucleotides?
a nitrogenous base, a phosphate group, and a pentose sugar
If a DNA sample were composed of 10% thymine, what would be the percentage of guanine?
A double-stranded DNA molecule contains a total of 120 purines and 120 pyrimidines. This DNA molecule could be composed of
120 thymine and 120 adenine molecules.
Which of the following statements best summarizes the structural differences between DNA and RNA?
DNA nucleotides contain a different sugar than RNA nucleotides.
A new organism is discovered in the forests of Costa Rica. Scientists there determine that the polypeptide sequence of hemoglobin from the new organism has 72 amino acid differences from humans, 65 differences from a gibbon, 49 differences from a rat, and 5 differences from a frog. These data suggest that the new organism
is more closely related to frogs than to humans.