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

Transcription

1 Summer Work Quiz - Molecules and Chemistry Name MULTIPLE CHOICE. Circle the one alternative that best completes the statement or answers the question. 1) The four most common elements in living organisms are 2) a) C, H, O, N. b) Fe, N, O, Ca. c) C, H, O, Fe. d) C, H, O, Na. e) C, N, O, Na. The hydrogen bonds shown in this figure are each a) between two oxygen atoms. b) between two atoms with the same charge. c) between an oxygen and a hydrogen atom of different water molecules. d) between two hydrogen atoms.!e) between an oxygen and a hydrogen atom of the same water molecule. 3) Organic compounds! a) always contain oxygen. b) always contain nitrogen.! c) are synthesized only by animal cells. d) can be synthesized only in a laboratory. e) always contain carbon.

2 4) Which of the following statements regarding carbon is false? a) Carbon has the ability to bond together to form extensive, branched, or unbranched "carbon skeletons." b) Carbon has the ability to bond with up to four other atoms. c) Carbon has the capacity to form polar bonds with hydrogen. d) Carbon has a tendency to form covalent bonds. e) Carbon has the capacity to form single and double bonds. 5) You now know that the old cliché "oil and water don't mix" is true. Why? a) Water exhibits polarity and oil does not. b) Oil is an organic compound and water is not. c) Oil is hydrophilic. d) Water is hydrophobic.! e) Oil exhibits polarity and water does not. 6) A hydroxyl group is! a) characteristic of proteins. b) hydrophobic.! c) also called a carbonyl group. d) basic.! e) characteristic of alcohols. 7) Which of the following is an amino group? a) NH 2 b) CH 3 c) COOH d) OH 8) Which of the following contains a carboxyl and an amino group? a) amino acids b) fats! c) vinegar d) ATP e) sugars 9) Which of the following statements about the monomers and polymers found in living organisms is false? a) Monomers serve as building blocks for polymers.

3 b) DNA is built from just four kinds of monomers. c) The monomers used to make polymers are essentially universal. d) Monomers are joined together by the process of hydrolysis. e) Cells typically make all of their macromolecules from a set of common monomers and a few other ingredients that are rare. 10) The results of dehydration synthesis can be reversed by a) the addition of a phosphate group. b) hydrolysis. c) condensation. d) polymerization.! e) the addition of an amino group. 11) Which list below consists of only polymers?! a) proteins, lipids, nucleic acids, amino acids b) sugars, amino acids, nucleic acids, lipids! c) proteins, lipids, nucleic acids, polysaccharides d) polysaccharides, lipids, amino acids, nucleic acids e) proteins, lipids, nucleotides, sugars 12) Many names for sugars end in the suffix a) -ose. b) acid c) -hyde d) -ing. e) -ase. 13) A disaccharide forms when! a) two monosaccharides join by hydrolysis. b) two monosaccharides join by dehydration synthesis.! c) a starch and a monosaccharide join by dehydration synthesis. d) two starches join by dehydration synthesis. e) two starches join by hydrolysis. 14) Cellulose differs from starch in that a) glycogen is formed by plants and cellulose by animals. b) most animals cannot break down cellulose, whereas starch is easily digested. c) cellulose is highly branched, whereas starch is unbranched. d) the monomers of cellulose are held together by covalent bonds,

4 whereas the monomers of starch are held together by hydrogen bonds. e) starch is made of glucose monomers, whereas cellulose is made of fructose monomers. 15) The storage form of carbohydrates is in animals and in plants. a) glycogen... starch b) cellulose... glycogen c) glycogen... cellulose d) starch... glycogen e) chitin... glycogen 16) Which of the following organisms contain the polysaccharide chitin? a) fungi and insects b) crustaceans and bacteria c) insects and plants d) plants and bacteria e) animals and plants 17) Fatty acids are a) composed of carbon, hydrogen, glycerol, and a phosphate group. b) hydrophobic.! c) components of DNA. d) composed of four linked rings.! e) composed of carbon, hydrogen, and oxygen in a 1:2:1 ratio. 18) A phospholipid is composed of a) one glycerol molecule linked to one phosphate group and two fatty acids. b) one glycerol molecule linked to three fatty acids.! c) one glycerol molecule linked to three phosphate groups. d) one fatty acid molecule linked to one glycerol molecule and two phosphate groups. e) one fatty acid molecule linked to three glycerol molecules. 19) Which of the following substances is a lipid?! a) enzymes b) cellulose c) steroids

5 20) A major type of lipid found in cell membranes is a) cellulose. b) glycerol.! c) triglycerides. d) waxes. e) phospholipids. 21) Proteins differ from one another because! a) the number of nitrogen atoms in each amino acid varies. b) the peptide bonds linking amino acids differ from protein to protein.! c) the sequence of amino acids in the polypeptide chain differs from protein to protein d) each protein contains its own unique sequence of sugar molecules.! e) the number of nucleotides found in each protein varies from molecule to molecule. 22) Peptide bonds a) link amino acids. b) are formed by a hydrolysis reaction. c) form between fatty acids. d) bind monosaccharides.! e) are used to form amino acids. 23) The primary structure of a protein is a) composed of two or more polypeptide chains. b) the amino acid sequence of the polypeptide chain. c) composed of irregular folds. d) maintained by hydrogen bonds. e) an α-helix or a β-pleated sheet. 24) Which of the following is an example of secondary structure in a protein? a) a fibrous shape b) an alpha helix! c) the joining of two polypeptide chains d) a particular amino acid sequence e) a globular shape 25) The tertiary structure of a polypeptide refers to a) the presence of pleated sheets.

6 b) the amino acids of which it is made.! c) the overall three-dimensional structure. d) its size.! e) the number of R groups it contains. 26) A protein containing more than one polypeptide chain exhibits the level of protein structure. a) primary b) tertiary c) secondary d) infinite e) quaternary 27) DNA differs from RNA because DNA! a) is always double-stranded, while RNA is never double-stranded. b) contains thymine in place of uracil.! c) contains the sugar ribose rather than the sugar deoxyribose. d) contains phosphate groups not found in RNA.! e) consists of a single rather than a double polynucleotide strand. 28) Which of the following statements best describes a compound?! a) A compound contains two or more different elements in a fixed ratio. b) A compound is a pure element.! c) A compound is exemplified by sodium. d) A compound is a solution.! e) A compound is less common than a pure element. 29) In the equation2h 2 +O 2 2H 2 O,! a) H 2, O 2, and H 2 O are all trace elements. b) only H 2 and O 2 are compounds. c) H 2, O 2, and H 2 O are all elements. d) only H 2 O is a compound.! e) H 2, O 2, and H 2 O are all compounds. 30) Which of the following particles is found in the nucleus of an atom? a) only protons b) protons and neutrons c) protons and electrons

7 d) only neutrons e) only electrons 31) What is the atomic mass of an atom that has 6 protons, 6 neutrons, and 6 electrons? a) 18 b) 8 c) 6 d) 12 e) 5 32) A radioactive isotope is an isotope that a) decays. b) has the same atomic mass, but a different atomic number than the common variant of the element. c) has more protons than the common variant of the element. d) has more electrons than the common variant of the element. e) is stable. 33) Which particles increase by one as we move from left to right in the elements on the periodic table? a) neutrons only b) neutrons and protons c) electrons and neutrons d) electrons only e) electrons and protons 34) The hydrogen atoms of a water molecule are bonded to the oxygen atom by bonds, whereas neighboring water molecules are held together by bonds. a) polar covalent... hydrogen b) hydrogen... ionic c) polar covalent... ionic d) ionic... covalent e) hydrogen... polar covalent 35) are weak bonds that are not strong enough to hold atoms together to form molecules but are strong enough to form bonds within and around large molecules. a) Ionic bonds b) Anionic bonds

8 c) Polar covalent bonds d) Hydrogen bonds e) Covalent bonds 36) Water molecules stick to other water molecules because a) water molecules are neutral, and neutral molecules are attracted to each other. b) the oxygen atoms of adjacent water molecules are attracted to one another. c) hydrogen bonds form between the hydrogen atoms of one water molecule and the oxygen atoms of other water molecules. d) covalent bonds form between the hydrogen atoms of one water molecule and the oxygen atoms of other water molecules. e) the hydrogen atoms of adjacent water molecules are attracted to one another. 37) The tendency of water molecules to stick together is referred to as a) cohesion. b) evaporation. c) transpiration. d) polarity. e) adhesion. 38) Which of the following is dependent on the ability of water molecules to form hydrogen bonds with other molecules besides water? a) the ability of certain insects to walk on the surface of water b) the movement of water from the roots of a tree to its leaves c) the evaporative cooling of skin surfaces d) the universality of water as a solvent e) the milder temperatures of coastal regions compared to inland areas 39) Water's surface tension and heat storage capacity is accounted for by its a) weight. b) mass.! c) hydrogen bonds. d) orbitals. e) size. 40) The temperature of evaporation is much higher for water than for alcohol. Without knowing more about the chemistry of alcohol, which of the following is the most logical chemical!explanation for this

9 phenomenon? a) Alcohol molecules are more cohesive than water molecules. This means that as alcohol molecules evaporate, they pull other alcohol molecules into the air along with them. b) Fewer hydrogen bonds form between alcohol molecules. As a result, less heat is needed for alcohol molecules to break away from solution and enter the air. c) Alcohol has a higher surface tension than water. This means that alcohol molecules can easily break away from other alcohol molecules and evaporate at a lower temperature. d) Water is a better solvent than alcohol. Therefore, alcohol can break covalent bonds easily and will not be restricted from evaporating from its solute. e) Ionic bonds form between alcohol molecules. These are the weakest type of bond and are easier to break than the hydrogen bonds between water molecules. 41) A solution with a ph of 7 is a) weakly basic. b) strongly acidic. c) neutral. d) strongly basic. e) weakly acidic. 42) Compared to a solution of ph 3, a solution of ph 1 is a) 10 times more basic. b) neutral.! c) 10 times more acidic. d) 100 times more acidic. e) 100 times more basic.