Chapter3TheMoleculesofCells：3章细胞的分子.doc

Chapter 3: The Molecules of Cells3.1. Propanol and isopropanol are isomers. This means that they haveA) the same molecular formula but different chemical properties.B) different molecular formulas but the same chemical properties.C) the same molecular formula and the same chemical properties.D) the same number of carbon atoms but different number of oxygen and hydrogen atoms.E) the same molecular formula, but propanol is the liquid form of the compound and isopropanol is the gaseous form.3.2. You know that the old clich “oil and water dont mix” is true. Why?A) Oil exhibits polarity and water does not.B) Water exhibits polarity and oil does not.C) Oil is hydrophilic.D) Water is hydrophobic.E) Oil is an organic compound and water isnt.3.3. Monosaccharides can be joined together by a process called dehydration synthesis. Which of the following statements is/are true of this process?A) One monomer loses a hydrogen atom, and the other loses a hydroxyl group.B) Electrons are shared between atoms of the joined monomers.C) H2O is formed as the monomers are joined.D) Covalent bonds are formed between the monomers.E) All of the above are true.3.4. The result of dehydration synthesis can be reversed byA) a condensation reaction.B) a hydrolysis reaction.C) digestion.D) polymerization.E) both B and C.3.5. Which list below consists only of molecules that are all polymers?A) Sugars, amino acids, nucleic acids, lipids.B) Proteins, lipids, nucleic acids, sugars.C) Proteins, lipids, nuclear acids, polysaccharides.D) Proteins, lipids, nucleotides, sugars.E) Polysaccharides, lipids amino acids, nucleic acids.3.6. Sucrose is formedA) from two glucose molecules.B) from two monosaccharides by a dehydration synthesis.C) when ionic bonds link two monosaccharides.D) when water molecules are added to two monosaccharides.E) A, B and C.3.7. GlycogenA) contains glucose molecules.B) contains C, H, and O atoms.C) is a polysaccharide.D) is a carbohydrate animals use to store energy.E) all of the above.3.8. A triglycerideA) consists of three fatty acids attached to glycerol.B) is hydrophobic.C) plays a role in energy storage.D) is a type of fat.E) all of the above.3.9. CholesterolA) is a steroid.B) is necessary for human life.C) is hydrophobic.D) contains one OH group.E) all of the above.3.10. The major type of lipid found in cell membranes isA) steroids.B) triglycerides.C) phospholipids.D) glycerol.E) waxes.3.11. Building muscle is an example ofA) hydrolysis.B) catabolism.C) gluconeogenesis.D) anabolism.E) proteolysis.3.12. Enzymes A) are proteins.B) function as catalysts.C) regulate chemical reactions in a cell.D) have structures that correspond to their function.E) all of the above.3.13. Proteins differ from one another becauseA) the peptide bonds linking amino acids differ from protein to protein.B) the sequence of amino acids in the polypeptide chain differs from protein to protein.C) each protein contains its own unique sequence of sugar molecules.D) the number of nucleotides found in each protein varies from molecule to molecule.E) the number of nitrogen atoms in each amino acid varies.3.14. Amino acids can be distinguished from one another byA) the number of R groups found on the amino acid molecule.B) the chemical properties of their R groups.C) the type of bond between the R group and the rest of the molecule.D) the chemical properties of their amino and carboxyl groups.E) all of the above.3.15. Peptide bondsA) hold the polypeptide chains of complex proteins together.B) form between fatty acids.C) are formed by hydrolysis reaction.D) link amino acids.E) none of the above.3.16. Which of the following may be affected by the denaturation of a protein?A) The shape of the protein.B) The function of the protein.C) The solubility of the protein in water.D) The number of amino acids in the protein.E) A, B, and C.3.17. The _ structure of a protein consists of a chain of amino acids assembled in a specific order.A) primary.B) secondary.C) tertiary.D) quaternary.E) none of the above.3.18. A protein containing more than one polypeptide chain exhibits _ level(s) of protein structure.A) one.B) two.C) three.D) four.E) five.3.19. NucleotidesA) contain nitrogenous bases.B) contain sugar molecules.C) contain phosphate groups.D) can be linked together to form a double helix.E) all of the above.3.20 DNA differs from RNA because DNAA) contains thymine in place of uracil.B) consists of a single rather than double polynucleotide strand.C) contains pentose rather than hexose sugars.D) contains phosphate groups.E) all of the above.Key Termsalpha helix amines amino acids amino group anabolic steroids carbohydrate carbon skeleton carbonyl group carboxyl group carboxylic acids cellulosedehydration reactiondenaturationdeoxyribonucleic acid (DNA)disaccharidedouble helixenzymes fatfunctional groupsgenesglycogenhydrocarbonshydrolysishydrophilichydrophobichydroxyl groupisomerslipidsmacromoleculesmonomersmonosaccharidesnitrogenous basenucleic acidnucleot