Chapter 5 Flashcards
Humans and mice differ because
A) their cells have different small organic molecules.
B) their cells make different types of large biological molecules.
C) their cells make different types of lipids.
D) their cells have some differences in the sequence of nucleotides in their nucleic acids.
E) their cells make different types of proteins.
D) their cells have some differences in the sequence of nucleotides in their nucleic acids.
Molecules with which functional groups may form polymers via dehydration reactions? A) hydroxyl groups B) carbonyl groups C) carboxyl groups D) either carbonyl or carboxyl groups E) either hydroxyl or carboxyl groups
E) either hydroxyl or carboxyl groups
Which of these molecules is not formed by dehydration reactions? A) fatty acids B) disaccharides C) DNA D) protein E) amylose
A) fatty acids
In animal metabolism, most of the monomers released by digestion of food macromolecules are metabolized to provide energy. Only a small portion of these monomers are used for synthesis of new macromolecules. The net result is that
A) water is generated by animal metabolism.
B) water is consumed by animal metabolism.
C) the water consumed is exactly balanced by the water generated, to maintain homeostasis.
D) water is consumed during homeostasis, but water is generated during periods of growth.
E) water is generated during homeostasis, but water is consumed during periods of growth.
B) water is consumed by animal metabolism.
Which of these classes of biological molecules consist of both small molecules and macromolecular polymers?
A) lipids
B) carbohydrates
C) proteins
D) nucleic acids
E) lipids, carbohydrates, proteins, and nucleic acids all consist of only macromolecular polymers
B) carbohydrates
Which of the following is not a polymer? A) glucose B) starch C) cellulose D) chitin E) DNA
A) glucose
What is the chemical reaction mechanism by which cells make polymers from monomers?
A) phosphodiester linkages
B) hydrolysis
C) dehydration reactions
D) ionic bonding of monomers
E) the formation of disulfide bridges between monomers
C) dehydration reactions
How many molecules of water are needed to completely hydrolyze a polymer that is 11 monomers long? A) 12 B) 11 C) 10 D) 9 E) 8
C) 10
Which of the following best summarizes the relationship between dehydration reactions and hydrolysis?
A) Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers.
B) Dehydration reactions eliminate water from lipid membranes, and hydrolysis makes lipid membranes water permeable.
C) Dehydration reactions can occur only after hydrolysis.
D) Hydrolysis creates monomers, and dehydration reactions break down polymers.
E) Dehydration reactions ionize water molecules and add hydroxyl groups to polymers; hydrolysis reactions release hydroxyl groups from polymers.
A) Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers.
Which of the following polymers contain nitrogen? A) starch B) glycogen C) cellulose D) chitin E) amylopectin
D) chitin
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?
A) C18H36O18
B) C18H32O16
C) C6H10O5
D) C18H10O15
E) C3H6O3
B) C18H32O16
The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are the α form. Which of the following could amylase break down? A) glycogen B) cellulose C) chitin D) glycogen and chitin only E) glycogen, cellulose, and chitin
A) glycogen
On food packages, to what does the term insoluble fiber refer? A) cellulose B) polypeptides C) starch D) amylopectin E) chitin
A) cellulose
A molecule with the chemical formula C6H12O6 is probably a A) carbohydrate. B) lipid. C) monosaccharide D) carbohydrate and lipid only. E) carbohydrate and monosaccharide only.
E) carbohydrate and monosaccharide only.
Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified? A) as a pentose B) as a hexose C) as a monosaccharide D) as a disaccharide E) as a polysaccharide
D) as a disaccharide
All of the following are polysaccharides except A) lactose. B) glycogen. C) chitin. D) cellulose. E) amylopectin.
A) lactose.
Which of the following is true of both starch and cellulose?
A) They are both polymers of glucose.
B) They are cis-trans isomers of each other.
C) They can both be digested by humans.
D) They are both used for energy storage in plants.
E) They are both structural components of the plant cell wall.
A) They are both polymers of glucose.
Which of the following is true of cellulose?
A) It is a polymer composed of enantiomers of glucose.
B) It is a storage polysaccharide for energy in plant cells.
C) It is digestible by bacteria in the human gut.
D) It is a major structural component of plant cell walls.
E) It is a polymer composed of enantiomers of glucose, it is a storage polysaccharide for energy in plant cells, it is digestible by bacteria in the human gut, and it is a major structural component of plant cell walls.
D) It is a major structural component of plant cell walls.
Humans can digest starch but not cellulose because
A) the monomer of starch is glucose, while the monomer of cellulose is galactose.
B) humans have enzymes that can hydrolyze the β glycosidic linkages of starch but not the α glycosidic linkages of cellulose.
C) humans have enzymes that can hydrolyze the α glycosidic linkages of starch but not the β glycosidic linkages of cellulose.
D) humans harbor starch-digesting bacteria in the digestive tract.
E) the monomer of starch is glucose, while the monomer of cellulose is glucose with a nitrogen-containing group.
C) humans have enzymes that can hydrolyze the α glycosidic linkages of starch but not the β glycosidic linkages of cellulose.
Which of the following statements concerning saturated fats is not true?
A) They are more common in animals than in plants.
B) They have multiple double bonds in the carbon chains of their fatty acids.
C) They generally solidify at room temperature.
D) They contain more hydrogen than unsaturated fats having the same number of carbon atoms.
E) They are one of several factors that contribute to atherosclerosis.
B) They have multiple double bonds in the carbon chains of their fatty acids.
A molecule with the formula C18H36O2 is probably a A) carbohydrate. B) fatty acid. C) protein. D) nucleic acid. E) hydrocarbon.
B) fatty acid.
Which of the following statements is true for the class of biological molecules known as lipids?
A) They are insoluble in water.
B) They are made from glycerol, fatty acids, and phosphate.
C) They contain less energy than proteins and carbohydrates.
D) They are made by dehydration reactions.
E) They contain nitrogen.
A) They are insoluble in water.
The label on a container of margarine lists ʺhydrogenated vegetable oilʺ as the major ingredient. What is the result of adding hydrogens to vegetable oil?
A) The hydrogenated vegetable oil has a lower melting point.
B) The hydrogenated vegetable oil stays solid at room temperature.
C) The hydrogenated vegetable oil has more ʺkinksʺ in the fatty acid chains.
D) The hydrogenated vegetable oil has fewer trans fatty acids.
E) The hydrogenated vegetable oil is less likely to clog arteries.
B) The hydrogenated vegetable oil stays solid at room temperature.
Which of the following is true regarding saturated fatty acids?
A) They are the predominant fatty acid in corn oil.
B) They have double bonds between carbon atoms of the fatty acids.
C) They are the principal molecules in lard and butter.
D) They are usually liquid at room temperature.
E) They are usually produced by plants.
C) 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) a steroid B) cellulose C) DNA D) an enzyme E) a contractile protein
A) a steroid
Which modifications of fatty acids will best keep triglycerides solid at warmer temperatures?
A) creating cis double bonds to the fatty acids
B) adding hydrogens to the fatty acids
C) creating trans double bonds to the fatty acids
D) adding hydrogens and trans double bonds to the fatty acids
E) adding cis double bonds and trans double bonds to the fatty acids
D) adding hydrogens and trans double bonds to the fatty acids
Why are human sex hormones considered to be lipids?
A) They are essential components of cell membranes.
B) They are not soluble in water.
C) They are made of fatty acids.
D) They are hydrophilic compounds.
E) They contribute to atherosclerosis.
B) They are not soluble in water.
All of the following contain amino acids except A) hemoglobin. B) cholesterol. C) antibodies. D) enzymes. E) insulin.
B) cholesterol.
The bonding of two amino acid molecules to form a larger molecule requires
A) the release of a water molecule.
B) the release of a carbon dioxide molecule.
C) the addition of a nitrogen atom.
D) the addition of a water molecule.
E) the release of a nitrous oxide molecule.
A) the release of a water molecule.
30) There are 20 different amino acids. What makes one amino acid different from another?
A) different side chains (R groups) attached to a carboxyl carbon
B) different side chains (R groups) attached to the amino groups
C) different side chains (R groups) attached to an α carbon
D) different structural and optical isomers
E) different asymmetric carbons
C) different side chains (R groups) attached to an α carbon
The bonding of two amino acid molecules to form a larger molecule requires which of the following?
A) removal of a water molecule
B) addition of a water molecule
C) formation of a glycosidic bond
D) formation of a hydrogen bond
E) both removal of a water molecule and formation of a hydrogen bond
A) removal of a water molecule
Polysaccharides, triacylglycerides, and proteins are similar in that they
A) are synthesized from monomers by the process of hydrolysis.
B) are synthesized from subunits by dehydration reactions.
C) are synthesized as a result of peptide bond formation between monomers.
D) are decomposed into their subunits by dehydration reactions.
E) all contain nitrogen in their monomer building blocks.
B) are synthesized from subunits by dehydration reactions.
Dehydration reactions are used in forming which of the following compounds?
A) triacylglycerides
B) polysaccharides
C) proteins
D) triacylglycerides and proteins only
E) triacylglycerides, polysaccharides, and proteins
E) triacylglycerides, polysaccharides, and proteins
Upon chemical analysis, a particular polypeptide was found to contain 100 amino acids. How many peptide bonds are present in this protein? A) 101 B) 100 C) 99 D) 98 E) 97
C) 99
What aspects of protein structure are stabilized or assisted by hydrogen bonds?
A) primary structure
B) secondary structure
C) tertiary structure
D) quaternary structure
E) secondary, tertiary, and quaternary structures, but not primary structure
E) secondary, tertiary, and quaternary structures, but not primary structure
How many different kinds of polypeptides, each composed of 12 amino acids, could be synthesized using the 20 common amino acids? A) 4^12 B) 12^20 C) 240 D) 20 E) 20^12
E) 20^12
Which bonds are created during the formation of the primary structure of a protein?
A) peptide bonds
B) hydrogen bonds
C) disulfide bonds
D) phosphodiester bonds
E) peptide bonds, hydrogen bonds, and disulfide bonds
A) peptide bonds
What maintains the secondary structure of a protein?
A) peptide bonds
B) hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond
C) disulfide bonds
D) hydrophobic interactions
E) hydrogen bonds between the R groups
B) hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond
Which type of interaction stabilizes the α helix and the β pleated sheet structures of proteins? A) hydrophobic interactions B) disulfide bonds C) ionic bonds D) hydrogen bonds E) peptide bonds
D) hydrogen bonds
Which level of protein structure do the α helix and the β pleated sheet represent?
A) primary
B) secondary
C) tertiary
D) quaternary
E) primary, secondary, tertiary, and quaternary
B) secondary
The amino acids of the protein keratin are arranged predominantly in an α helix. This secondary structure is stabilized by A) covalent bonds. B) peptide bonds. C) ionic bonds. D) polar bonds. E) hydrogen bonds.
E) hydrogen bonds.
The tertiary structure of a protein is the
A) bonding together of several polypeptide chains by weak bonds.
B) order in which amino acids are joined in a polypeptide chain.
C) unique three-dimensional shape of the fully folded polypeptide.
D) organization of a polypeptide chain into an α helix or β pleated sheet.
E) overall protein structure resulting from the aggregation of two or more polypeptide subunits.
C) unique three-dimensional shape of the fully folded polypeptide.
What type of covalent bond between amino acid side chains (R groups) functions in maintaining a polypeptideʹs specific three-dimensional shape? A) ionic bond B) hydrophobic interaction C) van der Waals interaction D) disulfide bond E) hydrogen bond
D) disulfide bond
