MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

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1 Exam Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Spider silk is made of 1) A) proteins. B) DNA. C) carbohydrates. D) lipids. E) RNA. 2) Which one of the following statements about spider silk is not true? 2) A) Cells from hamsters and cows can be genetically modified to produce spider silk. B) DNA determines the structure of silk proteins. C) Spiraling strands, which capture prey, can stretch up to four times their normal length and return to their original length with little sag. D) Spider silk is produced by glands in a spider's abdomen. E) By weight, spider silk is equal in strength to steel. 3) Characteristics of carbon that contribute to its ability to form an immense diversity of organic molecules include its A) capacity to form single and double bonds. B) ability to bond together to form extensive, branched, or unbranched "carbon skeletons." C) ability to bond with up to four other atoms. D) tendency to form covalent bonds. 3) 4) Hydrocarbons 4) A) consist of atoms linked exclusively by single bonds. B) are composed of carbon atoms that are attached to hydrogen skeletons. C) are inorganic compounds. D) contain only carbon and hydrogen atoms. 5) Propanol and isopropanol are isomers. This means that they have 5) A) different molecular formulas but the same chemical properties. B) the same number of carbon atoms but different numbers of oxygen and hydrogen atoms. C) the same molecular formula and the same chemical properties. D) the same molecular formula but different chemical properties. E) the same molecular formula, but propanol is the liquid form of the compound and isopropanol is the gaseous form. 6) Organic compounds 6) A) are synthesized by cells. B) always contain carbon. C) always contain carbon and are synthesized by cells. D) can only be synthesized in a laboratory. E) always contain nitrogen. 1

2 7) You now know that the old cliché "oil and water don't mix" is true. Why? 7) A) Water is hydrophobic. B) Oil exhibits polarity and water does not. C) Oil is hydrophilic. D) Oil is an organic compound and water is not. E) Water exhibits polarity and oil does not. 8) A hydroxyl group is 8) A) characteristic of alcohols. B) hydrophobic. C) characteristic of proteins. D) also called a carbonyl group. E) None of the choices are correct. 9) Which one of the following is an amino group? 9) A) NH2 B) CO C) COOH D) OH E) CH3 10) Which one of the following statements about the functional groups of organic compounds is not true? A) Many biological molecules have two or more functional groups. B) Functional groups help make organic compounds soluble in water. C) All functional groups include a carbon atom of the organic compound's skeleton. D) Functional groups help make organic compounds hydrophilic. E) Functional groups participate in chemical reactions. 10) 11) Which one of the following statements about the monomers and polymers found in living organisms is not true? A) DNA is built from just four kinds of monomers. B) The monomers used to make polymers are essentially universal. C) Monomers serve as building blocks for polymers. D) Cells typically make all of their macromolecules from a set of common monomers and a few other ingredients that are rare. E) Monomers are joined together by the process of hydrolysis. 11) 12) 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) Covalent bonds are formed between the monomers. C) H2O is formed as the monomers are joined. D) Electrons are shared between atoms of the joined monomers. 12) 13) The results of dehydration synthesis can be reversed by 13) A) polymerization. B) a hydrolysis reaction. C) digestion. D) a condensation reaction. E) a hydrolysis reaction and digestion. 2

3 14) Which list below consists of only polymers? 14) A) proteins, lipids, nucleotides, sugars B) polysaccharides, lipids, amino acids, nucleic acids C) proteins, lipids, nucleic acids, amino acids D) proteins, lipids, nucleic acids, polysaccharides E) sugars, amino acids, nucleic acids, lipids 15) The molecular formula of most monosaccharides represents a multiple of 15) A) CH2O. B) CHO. C) CH3O. D) CHO3. E) CHO2. 16) A molecule with the formula C 55 H 110 O 55 is probably a(n) 16) A) steroid. B) polysaccharide. C) wax. D) oil. E) protein. 17) Sucrose is formed 17) A) from two glucose molecules. B) from two monosaccharides by dehydration synthesis. C) when water molecules are added to two monosaccharides. D) when ionic bonds link two monosaccharides. E) when glucose and lactose are combined. 18) A disaccharide forms when 18) A) two monosaccharides join by dehydration synthesis. B) two starches join by dehydration synthesis. C) two monosaccharides join by hydrolysis. D) two starches join by hydrolysis. E) a starch and a monosaccharide join by dehydration synthesis. 19) Molecules that taste sweet 19) A) cause carbohydrates to break down into monomers that trigger the sweet taste reaction. B) include at least one carbohydrate monomer. C) have a shape that binds tightly to sweet taste receptors. D) are all carbohydrates. E) must bind to the sweet and bitter receptors. 20) Which one of the following lists contains only polysaccharides? 20) A) fructose, cellulose, and glucose B) starch, amino acids, and glycogen C) sucrose, starch, and cellulose D) cellulose, starch, and glycogen E) nucleotides, glycogen, and cellulose 3

4 21) Cellulose differs from starch in that 21) A) glycogen is formed by plants and cellulose by animals. B) the monomers of cellulose are held together by covalent bonds, whereas the monomers of starch are held together by hydrogen bonds. C) most animals cannot break down cellulose, whereas starch is easily digested. D) starch is made of glucose monomers, whereas cellulose is made of fructose monomers. 22) Foods that are high in fiber are most likely derived from 22) A) dairy products. B) plants. C) meat. D) fish. E) any of these choices. 23) Cows can derive nutrients from cellulose because 23) A) their intestinal tract contains cellulose-hydrolyzing microorganisms. B) they produce the enzymes that break down cellulose. C) their intestinal tract contains termites, which can break down cellulose. D) they chew their food so thoroughly that cellulose fibers are broken down. E) they convert cellulose into starch, which is easily broken down in the intestinal tract. 24) The storage form of carbohydrates in animals is and in plants is. 24) A) glycogen... starch B) cellulose... glycogen C) sucrose... glycogen D) starch... glycogen E) glycogen... cellulose 25) One way to convert an oil into a substance that is solid at room temperature is to 25) A) remove water, causing a dehydration synthesis reaction to occur. B) remove hydrogens, increasing the number of double bonds. C) put it in the refrigerator: when unsaturated fats cool, double bonds form and the fats solidify. D) add hydrogens, decreasing the number of double bonds in the molecules. E) add water and shake vigorously. 26) Which one of the following is not true about animal cell lipids? 26) A) Fats are a form of lipid that functions as energy-containing molecules. B) Phospholipids are important components of cell membranes. C) Steroids are lipids that function as signaling molecules. D) Many lipids function as enzymes. E) Cholesterol is a type of lipid used in cell membranes and as a starting material for making steroid hormones. 4

5 27) A diet high in animal products may increase the risk for atherosclerosis. This is because 27) A) most animal fats are unsaturated and most animal products contain high levels of steroids. B) most animal fats are used for energy storage and most animal products contain high levels of unsaturated fats. C) most animal fats are hydrogenated oils and most animal products contain high levels of phospholipids. D) most animal fats are saturated and most animal products contain high levels of triglycerides. E) most animal products contain high levels of unsaturated oils and anabolic steroids. 28) In salad dressings, oil quickly separates from vinegar because oils are 28) A) polar. B) hydrophilic. C) nonpolar. D) amphiphilic. E) heavier than water. 29) Suppose you wanted to make margarine using a plant oil. How would you alter the oil molecules to make the oil solid at room temperature? A) reduce the number of fatty acids attached to each glycerol B) attach more fatty acids to each glycerol C) add hydrogens to change the double bonds in the fatty acids to single bonds D) add a phosphate group to the glycerol E) use a larger glycerol 29) 30) Because water and oil don't mix, water is not very effective at washing away oily dirt. The ability of soap to mix with both water and oily dirt allows dirt to be washed away. Which statement provides the most logical chemical explanation for this phenomenon? A) Soap molecules have charged regions and neutral regions. The neutral regions are attracted to water molecules; the charged regions are attracted to oils. B) Soap molecules have both positively and negatively charged regions. The positively charged regions are attracted to water; the negatively charged regions are attracted to oil. C) Soap molecules carry no charge. As a result, soap can form an effective bridge between charged water molecules and neutral oil molecules. D) Soap molecules have charged regions and neutral regions; the charged regions are attracted to water molecules; the neutral regions are attracted to oils. E) Soap molecules have both positively and negatively charged regions. The negatively charged regions are attracted to water; the positively charged regions are attracted to oil. 30) 31) A triglyceride 31) A) plays a role in energy storage. B) is a type of fat. C) is hydrophobic. D) consists of three fatty acids attached to a glycerol. 32) Fatty acids with double bonds between some of their carbons are said to be 32) A) unsaturated. B) triglycerides. C) saturated. D) monoglycerides. E) completely hydrogenated. 5

6 33) If you want to promote the development of atherosclerotic disease, you would eat a diet high in 33) A) complex carbohydrates. B) fiber. C) protein. D) saturated fats. E) sugars. 34) If you were to add olive oil to your food as part of a diet to lower your risk of atherosclerotic disease, you would use olive oil that A) had lard added to it. B) was modified to be solid at room temperature. C) was hydrogenated. D) was liquid at room temperature. E) None of the choices are correct. 34) 35) A phospholipid is composed of 35) A) one glycerol molecule linked to three phosphate groups. B) one fatty acid molecule linked to three glycerol molecules. C) one glycerol molecule linked to one phosphate group and two fatty acid molecules. D) one fatty acid molecule linked to one glycerol molecule and two phosphate groups. E) one glycerol molecule linked to three fatty acid molecules. 36) Which one of the following substances is not a lipid? 36) A) cholesterol B) steroids C) wax D) cellulose E) triglycerides 37) A major type of lipid found in cell membranes is 37) A) triglycerides. B) phospholipids. C) glycerol. D) cellulose. E) waxes. 38) Which one of the following statements is not true about waxes? Waxes are 38) A) lipids. B) used by some insects and plants for protection. C) more hydrophobic than fats. D) nonpolar. E) used as a starting material for making steroids. 39) Which one of the following statements about anabolic steroids is not true? Anabolic steroids 39) A) can stimulate mood swings and violent behavior. B) cause a general buildup of muscle mass. C) chemically resemble testosterone. D) promote bone growth. E) often cause the body to reduce its normal output of sex hormones. 6

7 40) Which one of the following statements about androstenedione is not true? 40) A) Androstenedione is normally produced in the body and converted to testosterone. B) Taking androstenedione decreases levels of "good" cholesterol. C) Studies show that taking androstenedione greatly increases the production of male sex hormones. D) Taking androstenedione can lead to premature puberty and stunted growth. E) Taking androstenedione can increase the likelihood of cardiovascular disease, cancer, and breast enlargement in males. 41) A scientist suspects that the food in an ecosystem may have been contaminated with radioactive nitrogen over a period of months. Which of the following substances could be examined for radioactivity to test the hypothesis? A) the hair produced by humans living in the ecosystem B) the sugars produced during photosynthesis by plants growing in the ecosystem C) the cholesterol in the cell membranes of organisms living in the ecosystem D) the cell walls of plants growing in the ecosystem E) Any of these choices. 41) 42) Which one of the following statements is not true? Enzymes 42) A) have structures that correspond to their function. B) function as organic catalysts. C) regulate virtually all chemical reactions in a cell. D) are proteins that change the rate of chemical reactions. E) are typically consumed by the reactions they promote. 43) Proteins differ from one another because 43) A) the number of nitrogen atoms in each amino acid varies. B) the sequence of amino acids in the polypeptide chain differs from protein to protein. C) the number of nucleotides found in each protein varies from molecule to molecule. D) each protein contains its own unique sequence of sugar molecules. E) the peptide bonds linking amino acids differ from protein to protein. 44) Amino acids can be distinguished from one another by 44) A) the chemical properties of their R groups. B) the number of R groups found on the amino acid molecules. C) the chemical properties of their amino and carboxyl groups. D) the type of bond between the R group and the rest of the amino acid molecule. 45) Glucose molecules are to starch as are to proteins. 45) A) lards B) oils C) amino acids D) fatty acids E) waxes 7

8 46) Peptide bonds 46) A) form between fatty acids. B) are formed by a hydrolysis reaction. C) are used to form amino acids. D) link amino acids. E) None of the choices are correct. 47) Which one of the following will not be affected by the denaturation of a protein? 47) 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) the binding properties of the protein 48) Which of the following factors can result in the denaturation of a protein? 48) A) changes in salt concentration B) heat C) changes in ph D) chemicals that destroy hydrogen bonds E) All of the choices can result in the denaturation of a protein. 49) The structure of a protein consists of a chain of amino acids assembled in a specific order. A) secondary B) tertiary C) primary D) quaternary E) None of the choices are correct. 49) 50) Which one of the following is an example of secondary structure in a protein? 50) A) a particular amino acid sequence B) an alpha helix C) a globular shape D) the joining of two polypeptide chains E) a fibrous shape 51) The tertiary structure of a polypeptide refers to 51) A) the overall three-dimensional structure. B) its size. C) the number of R groups it contains. D) the presence of pleated sheets. E) the amino acids of which it is made. 52) A protein containing more than one polypeptide chain exhibits the level of protein structure. A) infinite B) secondary C) primary D) tertiary E) quaternary 52) 8

9 53) Which one of the following statements about Linus Pauling is not true? Linus Pauling 53) A) determined how hemoglobin carries oxygen. B) first described the two fundamental secondary structures of proteins. C) is the only person ever to receive two unshared Nobel Prizes. D) helped to produce a ban on nuclear testing. E) first described the double-helix shape of DNA. 54) Nucleotides 54) A) can be linked together to form nucleic acids. B) contain sugar molecules. C) contain nitrogenous bases. D) contain phosphate groups. 55) DNA differs from RNA because DNA 55) A) contains thymine in place of uracil. B) consists of a single rather than a double polynucleotide strand. C) contains phosphate groups. D) contains pentose rather than hexose sugars. 56) Genetic information is encoded in the 56) A) degree of saturation of fatty acids. B) linear sequence of amino acids in a polypeptide. C) quaternary structure of a protein. D) sequence of nucleotides in DNA. E) length of glycogen. 57) Which one of the following is not the proper pairing of a polymer and its monomer? 57) A) protein and amino acid B) triglyceride and steroid C) polysaccharide and monosaccharide D) nucleic acid and nucleotide E) All of the pairs properly reflect a polymer and its corresponding monomer. 58) A new "wonder food" is being distributed by a rival company. The researchers in your company determine that the "wonder food" contains only carbon, oxygen, and hydrogen. At this point, your researchers can say with certainty that the food A) includes proteins. B) includes nucleic acids. C) could only be made of triglycerides. D) could only be made of carbohydrates. E) does not include proteins or nucleic acids. 58) 9

10 59) The glucose produced by a plant is used to make the carbohydrate, proteins, fats, and nucleic acids of the plant. Which statement is true about the process of converting sugars into other molecules? A) Glucose contains all of the elements needed to produce the carbohydrates, but other elements must come from the soil if the plant is to produce fats, proteins, and nucleic acids. B) Glucose contains all of the elements needed to produce the carbohydrates and nucleic acids, but other elements must come from the soil if the plant is to produce proteins and fats. C) Glucose contains all of the elements needed to produce the carbohydrates and fats, but other elements must come from the soil if the plant is to produce proteins and nucleic acids. D) Glucose contains all of the elements needed to produce these other molecules. E) None of the substances in the other answers can be produced from glucose alone. 59) 10