Chapter Two
The atomic number of this atom (the figure) is A 6. B 4. C 10. D 12. E cannot be determined from the available information
A 6.
Which of the following is NOT a characteristic of saturated fats? A They contain at least one double bond. B They are a form of stored energy. C Their fatty acids pack tightly together. D They are usually solid at room temperature. E They are found in animals.
A They contain at least one double bond.
An unbranched polymer composed of simple sugars is A cellulose. B triglyceride. C starch. D glycogen. E glycoprotein.
A cellulose.
Decomposition reactions are commonly ________ reactions. A exothermic B endothermic C exchange D dehydration E anabolic
A exothermic
Pure water has a neutral pH because __________. A it dissociates into equal numbers of hydrogen and hydroxyl ions B it is composed of polar covalent bonds C it is composed of equal numbers of hydrogen and oxygen atoms D it is a natural buffer
A it dissociates into equal numbers of hydrogen and hydroxyl ions
Each nucleotide is composed of a(n) _____. A pentose sugar, phosphate, and nitrogenous base B adenine, thymine, guanine, uracil, and cytosine C pentose sugar and a nitrogenous base D ribose sugar, phosphate, and nitrogenous base
A pentose sugar, phosphate, and nitrogenous base
Lipids found in the cytoplasmic membranes of all eukaryotic cells are A phospholipids. B polyunsaturated fats. C waxes. D steroids. E triglycerides.
A phospholipids.
DNA is composed of repeating units of sugars, phosphates, and nucleic acids. This is an example of a A polymer. B monomer. C micelle. D lipid. E salt.
A polymer.
Which of the following is found in RNA but not DNA? A ribose B phosphate C deoxyribose D adenine E cytosine
A ribose
During the formation of a nucleic acid, such as DNA, the phosphate group of a new nucleotide covalently binds to _____ of the existing string of nucleotides. A the 3' carbon B the 5' carbon C the phosphate group D the nitrogenous base
A the 3' carbon
A stable atom has ________ in its valence shell. A 4 electrons B 8 electrons C 2 neutrons D 8 protons E 10 electrons
B 8 electrons
What is the common trait of all lipids? A They are used for energy storage. B They are at least partially hydrophobic. C They contain fatty acids. D They form bilayers.
B They are at least partially hydrophobic.
Which of the following is NOT a characteristic of phospholipids? A They are found in cellular membranes. B They contain fatty acids that associate with water. C They contain two fatty acids and a phosphate functional group. D They can form micelles and bilayers. E They contain a hydrophilic phosphate "head".
B They contain fatty acids that associate with water.
The type(s) of bond produced when atoms share electrons equally is/are A an ionic bond. B a nonpolar covalent bond. C a polar covalent bond. D a hydrogen bond. E both polar covalent and ionic bonds.
B a nonpolar covalent bond.
Which of the following is NOT a normal function of nucleotides? A building blocks of RNA B building blocks of proteins C building blocks of DNA D energy storage molecules
B building blocks of proteins Amino acids, not nucleotides, are the building blocks of proteins.
Cranberry juice has a pH of 2.4, while grape juice has a pH of 3.3; which juice has more H+ ions? A grape juice B cranberry juice C neither; these juices are both basic D cannot be determined without more information
B cranberry juice
Which of the following does not contribute significantly to the mass of an atom? A isotope B electron C element D neutron E proton
B electron
Matter composed of a single type of atom is known as a(n) A compound. B element. C mineral. D molecule. E electron.
B element.
A phosphate is moved from one molecule to another. This is an example of a/an ________ reaction. A anabolic B exchange C exothermic D endothermic E catabolic
B exchange
The reverse of a dehydration synthesis reaction is a(n) ________ reaction. A endothermic B hydrolytic C anabolic D metabolic E exchange
B hydrolytic
When the nucleus of an atom contains a constant number of protons but a variable number of neutrons, the atom is called a(n) _____. A dalton B isotope C valence D element
B isotope
Which of the following is not a type of lipid? A steroids B peptidoglycan C triglycerides D waxes
B peptidoglycan
Which of the following is found in nucleic acids? A glycerol B purines C amines D carboxylic acid E R group
B purines
An endothermic reaction __________. A exchanges energy B requires energy C releases energy D creates energy
B requires energy
The difference between ribose sugars and deoxyribose sugars is that _____. A ribose sugars are six-carbon sugars, whereas deoxyribose sugars are five-carbon sugars B ribose sugars have an extra oxygen atom C deoxyribose sugars already have a phosphate attached D ribose sugars compose purines and deoxyribose sugars compose pyrimidines
B ribose sugars have an extra oxygen atom
The high amount of energy stored within a molecule of the nucleotide adenosine triphosphate may be found _____. A within the bond between the nitrogenous base and ribose sugar B within the phosphate-phosphate bonds C within the bonds of the ribose sugar D within the bond between the nucleoside and the first phosphate
B within the phosphate-phosphate bonds (The covalent bonds between the phosphates release more energy than the sum of the two phosphates independently and are considered high-energy bonds.)
If you know that sodium chloride molecules contain ionic bonds, which of the following electronegativity values would be appropriate for the elements sodium and chlorine? A 3.0 and 4.0 B 1.0 and 1.2 C 0.9 and 3.0 D 3.0 and 2.8
C 0.9 and 3.0
All of the following are associated with ATP molecules EXCEPT A three phosphate groups. B high-energy bonds. C a long-term energy supply. D formation of coenzymes. E a recyclable energy supply.
C a long-term energy supply.
Which of the following is a bond in which electrons are shared unequally? A an ionic bond B either a polar or a nonpolar covalent bond C a polar covalent bond D a nonpolar covalent bond
C a polar covalent bond
Nucleosides differ from nucleotides in that nucleosides _____. A have a two-ring nitrogenous base B are incapable of forming bonds C are missing a phosphate D are missing a sugar
C are missing a phosphate
KH2PO4 acts as a buffer by __________. A releasing hydroxyl ions B releasing H2O C combining with hydrogen ions D combining with hydroxyl ions
C combining with hydrogen ions
The nucleotide _____ is an important signaling molecule within many cells. A adenosine B adenine C cyclic adenosine monophosphate D adenosine triphosphate
C cyclic adenosine monophosphate (Cyclic AMP is useful as a signaling molecule, but not as a major source of energy.)
Catabolism includes all of the following types of reactions EXCEPT __________. A hydrolysis reactions B exothermic reactions C dehydration synthesis reactions D decomposition reactions
C dehydration synthesis reactions
Which parts of the atoms interact in a chemical reaction? A isotopes B neutrons C electrons D ions E protons
C electrons
A synthesis reaction is also considered which of the following types of reactions? A decomposition B catabolism C endothermic D hydrolysis
C endothermic
Methane is classified as a compound because __________. A its atoms share electrons B its bonds are covalent C it contains atoms of more than one element D it has four bonds
C it contains atoms of more than one element
What type of charge does an electron have? A ions B positive C negative D neutral
C negative
All of the following are components of an amino acid EXCEPT a(n) A amino group. B α-carbon. C pentose group. D carboxyl group. E R group.
C pentose group.
A(n) ________ is a compound that dissolves into anions and cations in water. A proteins B carbohydrates C peptidoglycan D waxes E sterols
C peptidoglycan
A protein is a ________ of amino acids. A solution B bilayer C polymer D decomposition product E monomer
C polymer
In discussions of atomic mass, electrons are often ignored because __________. A they do not have an atomic mass B some atoms do not have very many electrons C their mass makes a negligible contribution to the atom's overall mass D their mass is cancelled out by the mass of the protons in the atom
C their mass makes a negligible contribution to the atom's overall mass
Mycobacterium tuberculosis is resistant to drying due to the presence of ________ in its cell wall. A sterols B peptidoglycan C waxes D proteins E carbohydrates
C waxes
Which of the following is an organic compound? A CO2 B O2 C H2O D C6H12O6 E NaCl
D C6H12O6
Which of the following is NOT true of hydrogen bonds? A The cumulative effect of many hydrogen bonds can stabilize the three-dimensional shape of large molecules B Hydrogen bonds are weak and can be broken easier than covalent of ionic bonds C They can play a role crucial role in enzyme function. D Hydrogen bonds are important only in the interaction between water molecules.
D Hydrogen bonds are important only in the interaction between water molecules. (Many of water's properties do arise from the hydrogen bonds; however, hydrogen bonds are important in many other molecules, for example DNA and protein.)
Which of the following is a property of water? A It is not a common reactant in metabolic reactions. B It is a nonpolar molecule. C It is not a good solvent. D It has a high capacity for heat. E It is liquid in a very narrow temperature range.
D It has a high capacity for heat.
The type(s) of bond produced when atoms with somewhat different electronegativities share electrons is/are A a nonpolar covalent bond. B a hydrogen bond. C an ionic bond. D a polar covalent bond. E both nonpolar covalent and ionic bonds.
D a polar covalent bond.
The valence of an atom represents its A electronegativity. B ability to attract electrons. C atomic mass. D ability to interact with other atoms. E isotopic state.
D ability to interact with other atoms
An acid dissociates in water to release A hydroxyl group(s). B hydrogen ion(s). C cation(s). D both anions and hydrogen ions. E anion(s).
D both anions and hydrogen ions.
Amino acids can combine with either hydroxyl or hydrogen ions. As a result, they can function as A solvents. B cations. C transfer groups. D buffers. E salts.
D buffers.
Which of the following are examples of pyrimidines? A thymine and adenine B cytosine and guanine C thymine and guanine D cytosine and thymine E uracil and adenine
D cytosine and thymine
A(n) ________ is an arrangement of atoms found in a variety of macromolecules and serves as their primary reactive end. A salt B buffer C isotope D functional group E stereoisomer
D functional group
The double-strands of DNA result from the formation of ________ between the bases. A peptide bonds B covalent bonds C ionic bonds D hydrogen bonds E α-1,4 bonds
D hydrogen bonds
All of the following bases are found in RNA molecules EXCEPT A uracil. B guanine. C cytosine. D thymine. E adenine.
D thymine.
Organisms use carbohydrates in all of the following ways EXCEPT A as a component of cell walls. B as a long-term energy source. C as a building block of DNA and RNA molecules. D to keep membranes flexible at low temperatures. E as a short-term energy source.
D to keep membranes flexible at low temperatures.
Which of the following is an example of a polysaccharide? A glucose B deoxyribose C fructose D sucrose E glycogen
E glycogen
Denaturation of a protein is always permanent. True/False
FALSE
Hydrogen bonds are stronger then covalent bonds. True/False
FALSE
The long-term chemical energy storage molecules in plants are steroids. True/False
FALSE
The smallest chemical units of matter are elements. True/False
FALSE
All electron shells of atoms hold eight electrons each. True/False
FASLE
A molecule composed of carbon and hydrogen is a compound. True/False
TRUE
Dehydration synthesis is a common feature of polymer production in cells. True/False
TRUE
Matter composed of a single type of atom is an element. True/False
TRUE
Salts are produced from exchange reactions in which acids and bases neutralize each other. True/False
TRUE
A(n) (catalyst/enzyme/intermediate) is any molecule that speeds up a chemical reaction.
catalyst
An atom or molecule becomes a(n) (anion/ion/cation) when it loses an electron to a more electronegative molecule.
cation
When a base dissolves in water it releases a(n) (anion/cation/hydrogen ion).
cation
Cell markers composed of both carbohydrate and lipid molecules are known as (glycoproteins/glycolipids/glycogen).
glycolipids
The DNA double helix is held together by (covalent/ionic/hydrogen) bonds.
hydrogen
A chemical reaction in which a water molecule is a reactant is known as a (dehydration/hydrolysis) reaction.
hydrolysis
Radioactive iodine is sometimes used to treat thyroid cancer. This is an example of the use of (isotopes/elements/radiation) in medical treatment.
isotopes
The (atoms/isotopes/stereoisomers) of an element vary in the number of neutrons in the nucleus.
isotopes
Steroids are (branched/multi-ringed/unbranched) hydrocarbons.
multi-ringed
A(n) (nonpolar/polar/ionic/hydrogen) bond is one in which electrons are shared equally between atoms.
nonpolar
The monomer of a nucleic acid is called a (nucleoside/nucleotide/base).
nucleotide
the figure depicts the (primary/secondary/tertiary) structure of a protein.
primary
A nitrogenous base composed of two rings is a (purine/pyrimidine/ribose).
purine
The folding of a polypeptide into a three-dimensional shape is its (secondary/tertiary/quaternary) structure.
tertiary