Chapter 2: The Chemistry of Life
Which is an example of a nucleotide?
ATP
A base is a compound that acts as a proton ______.
Acceptor
A proton (H+) donor, or a chemical that releases protons into solution, is a(n) _______.
Acid
HCl is a compound that releases hydrogen ions when put into water. Therefore, it is a(n) ______.
Acid
Solution A has a pH of 2. It is ______.
Acidic
The pH of the stomach can be as low as 2. This pH is considered to be which of the following?
Acidic
The energy required to initiate or begin a chemical reaction is called its ________ energy.
Activation
Which term refers to the energy needed to get a chemical reaction started?
Activation energy
The substrate-binding site of an enzyme is known as the _________ site.
Active
Which molecule combines with an inorganic phosphate to form ATP?
Adenosine diphosphate
The energy molecule that is produced by cellular respiration and used in metabolic reactions is ______.
Adenosine triphosphate
Which molecule, composed of adenine, ribose, and three phosphate groups, functions as an energy-transfer molecule?
Adenosine triphosphate
Which of the following is a type of connective tissue that provides energy storage, thermal insulation, and protective cushioning?
Adipose tissue
Which type of molecule is most likely to have a hydroxyl functional group?
Alcohols
Which secondary structure of proteins has a spiral shape?
Alpha helix
Indicate how pH and temperature affect the activity of an enzyme.
Altering the shape of the substrate binding site Causing a conformational change in the enzyme
Name the functional group with the symbol -NH2.
Amino
The monomer subunits of proteins always have which of the following functional groups?
Amino
Which of the following are names of functional groups that are commonly found in organic molecules?
Amino Hydroxyl Carboxyl
Peptide bonds are used to join two of these together.
Amino acids
Which of the following are the monomeric subunits that make up a protein?
Amino acids
Which of the following is most likely to contain a carboxyl functional group?
Amino acids
Which term refers to the dual nature of phospholipids, which contain both hydrophilic and hydrophobic groups?
Amphipathic
Molecules described as _________, such as phospholipids, contain both a hydrophobic and a hydrophilic region.
Amphiphilic
Which is an enzyme?
Amylase
What is an ion?
An atom that has gained or lost electrons
Which occurs when the demand for ATP out-paces the oxygen supply?
Anaerobic fermentation
The chlorine atom gains electrons to become a chloride ______.
Anion
Which term refers to a negatively charged ion?
Anion
A chemical that neutralizes free radicals is called a(n) ______.
Antioxidant
Which are examples of electrolytes?
Bases Acids Salts
A pH of 7.5 is considered to be which of the following?
Basic
Solution B has a pH of 10. It is ______.
Basic
The secondary structure of proteins that is a ribbon-like shape is called a(n) _________ pleated sheet.
Beta
Name the secondary structure of proteins that has a pleated, ribbon-like shape.
Beta sheet
The study of the molecules and chemical reactions that occur in living cells is called
Biochemistry
Which term means the study of the molecules and chemical reactions that occur in living cells?
Biochemistry
Which of the following is another term for enzyme?
Biological catalyst
Which of the following is an example of a suspension?
Blood cells in blood plasma
Substances that resist changes in pH are known as ________.
Buffer
Which of the following is an example of a mineral?
Calcium
What are the six most abundant (by weight) elements that account for 98.5% of the body weight.
Calcium Oxygen Phosphorus Nitrogen Carbon Hydrogen
The amount of thermal energy that will raise the temperature of 1 g of water by 1°C defines which unit?
Calorie
Phosphorylation of an enzyme ______.
Can turn off a metabolic pathway Can activate a metabolic pathway
Polysaccharides are examples of what type of molecule?
Carbohydrate
The ______ family of macromolecules are composed of carbon, hydrogen and oxygen in a 1:2:1 ratio and includes sugars, starches, glycogen, and cellulose.
Carbohydrate
What is the prosthetic group in a glycoprotein molecule?
Carbohydrate
Monosaccharides, disaccharides, and polysaccharides are all examples of which type of macromolecule?
Carbohydrates
The element that is the foundation of biological molecules is ______ . This element has four valence electrons and can form a wide variety of bonds.
Carbon
Which element is the foundation of biological molecules? Hint: it is able to form a wide variety of compounds because it has four valence electrons.
Carbon
In nature, sodium atoms loses electrons; therefore, they become ______.
Cations
The structural polysaccharide found in plant cells is ________.
Cellulose
Which of the following is a type of plant saccharide that is commonly found in our diet, even though we do not have the enzymes to digest it?
Cellulose
Covalent, ionic, and hydrogen are examples ________ of bonds
Chemical
Which term refers to an attractive force caused by the sharing or transfer of electrons?
Chemical bond
Which of the following best describes a polar covalent bond?
Electrons are shared unequally between two atoms.
A pure chemical substance that consists of one type of atom is called a(n) _______.
Element
Which term defines the simplest form of matter to have unique chemical properties?
Element
A suspension of liquid fat in water is an example of which of the following?
Emulsion
A starch molecule may contain thousands of smaller glucose subunits. Which of the following statements is true?
Glucose is a monomer of starch.
Identify the components of a triglyceride below. Choose all that apply.
Glycerol Three fatty acids
A glucose polymer synthesized by liver, muscle, uterine, and vaginal cells that serves as an energy-storage polysaccharide is a __________ molecule.
Glycogen
Identify the polysaccharide used for energy storage in animals.
Glycogen
Van der Waals forces are important in ______.
the association of lipid molecules within cell membranes protein folding binding proteins to each other
A phospholipid molecule with a carbohydrate covalently bonded to it is called a(n) _______. It can be found in the plasma membranes of cells.
Glycolipid
A protein molecule bonded to a smaller carbohydrate molecule is called a ______.
Glycoprotein
A protein molecule with a smaller carbohydrate covalently bonded to it is called a(n) ______.
Glycoprotein
Water molecules are weakly attracted to each other through ______ bonds.
Hydrogen
Which type of bond can be described as a weak attraction between a slightly positive region in one molecule and a slightly negative region in a different molecule?
Hydrogen
Solution A prevents solution C from changing its pH. Solution A is therefore a what?
Hydrogen ions
Which term is used to describe a series of reactions, where each step is catalyzed by a specific enzyme?
Metabolic pathway
Fats have an abundance of which functional group?
Methyl
Inorganic elements that are extracted from the soil by plants and passed up the food chain are known as ________.
Minerals
Salt on a watermelon is an example of a ______.
Mixture
Substances that are physically blended but not chemically bound are called __________.
Mixture
Name the measure of concentration that takes into consideration the number of solute molecules.
Molarity
The measure of chemical concentration, expressed as moles of solute per liter of solution, is known as _______.
Molarity
The number of molecules of a chemical that is equal to its molecular weight in grams, is a(n) _________.
Mole
A structure that is composed of two or more atoms that are held together by chemical bonds is called a(n) _______.
Molecule
Which of the terms below can be applied to glucose (C6H12O6)?
Molecule Compound
Which of the following would give you the molarity of a solution?
Moles/liter
Identify the term used to name one of the identical or similar subunits of a larger molecule. Multiple choice question.
Monomer
Which term is used to refer to a simple sugar, or sugar monomer?
Monosaccharide
Disaccharides can be broken down into ______.
Monosaccharides
Glucose, fructose and galactose are examples of which of the following?
Monosaccharides
Which term applies to a solution with a pH of 7.0?
Neutral
The six most abundant elements in the human body are carbon, oxygen, hydrogen, phosphorus, calcium, and _______.
Nitrogen
Which of the following is an acidic polymer of nucleotides, found or produced in the nucleus, that functions in heredity and protein synthesis?
Nucleic acid
Which molecule is most likely to have a phosphate functional group?
Nucleic acids
Which organic molecules are composed of a nitrogenous base, a monosaccharide, and a phosphate group?
Nucleotides
Sucrase digests ______.
Only sucrose
Name the type of bond that holds amino acids together in a protein molecule.
Peptide bond
Which of the following are used to express concentration?
Percentages Molarity Weight per volume
Nucleic acids contain which functional group?
Phosphate
Any enzyme that adds an inorganic phosphate (Pi) group to another organic molecule is known as a(n) ________.
Phosphokinase
A lipid that consists of two hydrophobic fatty acid tails and a hydrophilic phosphate head is called a(n) _______.
Phospholipids
Which of the following molecules are the major component of the plasma membrane?
Phospholipids
Addition of an inorganic phosphate (Pi) group to an organic molecule is known as the process of ________.
Phosphorylation
Addition of an inorganic phosphate (Pi) group to an organic molecule is known as the process of _________.
Phosphorylation
Kinases catalyze which type of reaction?
Phosphorylation
What term refers to a covalent bond in which the electrons are not equally shared?
Polar
What term refers to a covalent bond in which the electrons are not equally shared? Multiple choice question.
Polar
A large molecule that consists of many identical or similar subunits, such as protein, DNA, or starch is a(n) _______.
Polymer
Proteins are macromolecules composed of numerous amino acids. Based on this, which term describes proteins?
Polymers
Which type of fatty acid has two or more double bonds within its carbon chain?
Polyunsaturated
A cation has a net _________ charge.
Positive
Name the level of protein structure that is determined by the amino acid sequence of the protein.
Primary
The structure of a protein that is its amino acid sequence is called __________ structure.
Primary
Which type of eicosanoid is a modified fatty acid with a single five-carbon ring?
Prostaglandin
A heme moiety (non-amino acid component) attached to the protein hemoglobin is an example of which of the following?
Prosthetic group
The most common colloids in the body are mixtures of water and what other substance?
Protein
Which of the following always contains an amino functional group?
Protein
A polymer of amino acids are classified as which of the following?
Proteins
Amino acids are the subunits of larger molecules called ______.
Proteins
Most biological colloids are composed of _______ dissolved in water.
Proteins
Name the family of macromolecules that plays a role in cell structure, communication (hormones and neurotransmitters), membrane transport, catalysis (enzymes), recognition and protection (immune factors), movement (contractile molecules), and cell adhesion.
Proteins
Which term refers to a molecule composed predominantly of a carbohydrate covalently bonded to a smaller protein component?
Proteoglycan
Which term below refers to large molecules composed of covalently-bonded carbohydrate and protein groups? Hint: They usually serve as lubricants at joints or as a structural component of cartilage.
Proteoglycans
The level of protein structure that is determined by the interactions between two or more polypeptide chains within a protein is the ________ level.
Quaternary
Which three groups are part of the basic structure of every amino acid?
Radical (R group) Amino group Carboxyl group
Which would require more calories?
Raising the temperature of 1 gram of water 1 degree Celsius
A fatty acid contains the maximum number of hydrogens possible. It is ______.
Saturated
Which are classifications of fatty acids?
Saturated and Unsaturated
An alpha helix is an example of _________ structure found in proteins.
Secondary
Name the level of protein structure that is determined by the folding of the protein into alpha helices and beta sheets due to hydrogen bonding between amino acids.
Secondary
The level of protein structure that is determined by the folding of the protein due to hydrogen bonding between amino acids to form alpha helices and beta-pleated sheets is called the ________ level.
Secondary
Which best describes the functional role of cyclic adenosine monophosphate (cAMP)?
Serves as a chemical messenger in cells
Which of the following best describes a covalent bond?
Sharing of electrons between two atoms
Saltwater is a solution made out of NaCl (salt) dissolved in water. In this case, water is the solvent and NaCl is the ________.
Solute
The particles of matter that are dissolved in a solution are known as what?
Solute
A substance consisting of a solute mixed with a more abundant substance called the solvent is called a(n) _______.
Solution
Which term defines a substance that consists of a solute dissolved in a more abundant substance called the solvent?
Solution
The ability of water to dissolve other chemicals is ______.
Solvency
In a solution, the more abundant substance that dissolves another substance is known as what?
Solvent
Saltwater is a solution of NaCl dissolved in water. In this example, NaCl is the solute and water is the ______.
Solvent
The lock and key model describes the property of enzyme-substrate ________.
Specificity
An energy-storage polysaccharide in plants is called ________.
Starch
Which of the following is the only plant polysaccharide that humans can digest?
Starch
Estrogen and testosterone are examples of which type of lipid?
Steroids
The general term for a lipid molecule that consists of four interconnected carbon rings is ________. Examples are cholesterol, testosterone, or estrogen.
Steroids
Keratin and collagen are types of ______ proteins.
Structural
The substance that an enzyme acts upon is called the ______.
Substrate
Which term refers to the substance upon which an enzyme acts?
Substrate
Blood cells in the blood plasma is a biological example of which type of mixture?
Suspension
List the factors that affect enzyme conformation.
Temperature and pH
The folding of proteins into various globular and fibrous shapes is referred to as the ________ structure of the proteins.
Tertiary
Which level of protein structure is due to bending and folding into various globular and fibrous shapes?
Tertiary
What is the active site of an enzyme?
Where it binds its substrate
In a solution, the solute ______, when the solution is allowed to stand.
Will not separate from the solvent
Adding together the atomic weights of all atoms in a molecule gives a value known as its _________ weight.
molecular
The abbreviation ________ is a measurement of acidity derived from the concentration of H+.
pH
Colloids are chemical mixtures that contain ______.
particles smaller than 100 nm suspended particles that scatter light
One millimole of NaCl is dissolved in a liter of water. What is the concentration of Na+ in the solution?
1 mEq/L
Hydrogen has an atomic weight of 1amu and oxygen has an atomic weight of 16amu. What is the molecular weight of water (H2O)?
18amu
A double covalent bond involves how many pair(s) of shared electrons?
2
A neutral solution has a pH of ______.
7
Which of the following best describes the chemical reaction called hydrolysis?
A covalent bond is broken by adding an OH to one side of the molecule, and an H to the other side.
Which of the following best describes a glycolipid?
A phospholipid molecule covalently bonded to a carbohydrate
Which best describes what occurs in a condensation reaction?
A water molecule is removed from a molecule when it creates a covalent bond.
Which steroid is a precursor for all other steroids in the body?
Cholesterol
Which steroid molecule are all of the other steroids derived from?
Cholesterol
NADH is a small organic molecule that is needed for an enzyme to work properly. NADH is a(n) ______.
Coenzyme
Which term refers to a small organic molecule, usually derived from a vitamin, that is needed to make an enzyme catalytically active?
Coenzyme
Which term refers to an organic cofactor that is required for an enzyme to function?
Coenzyme
Which term refers to a nonprotein, such as a metal ion or a coenzyme, that is needed for some enzymes to function?
Cofactor
A chemical mixture containing particles that are too large to pass through most selectively permeable membranes, but small enough to remain evenly dispersed through the solvent is called a(n) ________.
Colloid
An enzyme associated with its substrate is referred to as an enzyme-substrate ______.
Complex
Polymers formed of many simple sugars are classified as ______.
Complex carbohydrates Polysaccharides
Which term can apply to a molecule composed of two or more different elements?
Compound
Weight per volume, percentages, and molarity are different measures of ________.
Concentration
Which are examples of nucleic acids?
DNA and RNA
Sucrose or table sugar is formed when the simple sugars fructose and glucose are covalently bonded. This reaction releases water. What is the name of this type of reaction?
Dehydration synthesis
Which term refers to a change in the three-dimensional conformation of a protein that destroys its functional properties?
Denaturation
A carbohydrate composed of two covalently-bonded simple sugars (monosaccharides) is called a(n) ______.
Disaccharides
Which is a 20-carbon compound derived from arachidonic acid?
Eicosanoids
Choose the lipids in the list below.
Eicosanoids Fatty acids Phospholipids Triglycerides Steroids
A substance that dissociates in water and produces a solution that can conduct electricity is called a(n) _________.
Electrolyte
A compound that dissociates in water, producing a solution that conducts electricity, is known as a(n) _______.
Electrolytes
Which term is used to describe the structure formed by the combining of the enzyme and its specific substrate?
Enzyme-substrate complex
Each enzyme catalyzes one particular chemical reaction. Which term describes this property of enzymes?
Enzyme-substrate specificity
Which of the following statements about enzymes are true?
Enzymes show enzyme-substrate specificity. Enzymes are not consumed in the reactions they catalyze. Enzymes speed up reaction rates by lowering the activation energy of a specific reaction.
Some fatty acids must be obtained from the diet because the body cannot synthesize them. The term given to this group of compounds is ________ fatty acids.
Essential
Which term specifically refers to fatty acids that must be eaten since the human body is unable to synthesize them?
Essential fatty acids
An enzyme is consumed by the reaction it catalyzes.
False; The enzyme is not one of the reactants, so therefore is not consumed in the reaction.
Unsaturated fatty acids do not have double bonds.
False; it may contain one or more double bonds
Saturated fatty acids contain one or more double bonds.
False; no double bonds
Free radicals have an even number of electrons.
False; odd
Which is an example of an emulsion?
Fat in breast milk
Which molecule is most likely to contain methyl groups?
Fats
A molecule consisting of a carbon chain, with 4 to 24 carbons, with a methyl group on one end and a carboxyl group on the opposite end is which of the following?
Fatty acid
Which type of particle has an unpaired electron, making it highly reactive and destructive to cells?
Free radical
Groups of atoms that are added to carbon backbones and that give organic molecules a variety of unique properties are generally known as ________ groups.
Functional
Which of the following terms refers to common arrangements of atoms that give organic molecules their unique properties?
Functional groups
Choose all the statements that correctly describe guanosine triphosphate.
GTP is a nucleotide. GTP may donate a phosphate to help regenerate ATP.
Choose the monosaccharides from the list below.
Galactose, Fructose, Glucose
Name the monosaccharide (C6H12O6), also known as blood sugar.
Glucose
Which is a monosaccharide that provides energy to most body cells?
Glucose
Name the chemical reaction that breaks a covalent bond in a molecule by adding an OH group to one side of the bond and H to the other side, thus consuming a water molecule.
Hydrolysis
Which term refers to molecules that dissolve in water?
Hydrophilic
What term can be used to describe any molecule that is non-polar and does not dissolve in water?
Hydrophobic
Which of the following functional groups is typically found in an alcohol?
Hydroxyl
What are the functions of adipose tissue?
Insulation, cushioning, energy storage.
What does the quaternary structure of a protein depend upon?
Interactions between multiple polypeptide chains
An atom or molecule that has gained or lost electrons is called a(n)
Ion
A chemical bond that involves the attraction of a cation to an anion is called a(n) ________ bond.
Ionic
Glucose and fructose both have the chemical formula C6H12O6. Which term below describes the relationship between glucose and fructose?
Isomers
Molecules with the same molecular formula but different arrangements of their atoms are known as _______.
Isomers
What is the toxic end product of anaerobic fermentation?
Lactic Acid
________ is the disaccharide found in milk sugar.
Lactose
Choose the disaccharides from the list below.
Lactose Sucrose Maltose
A hydrophobic organic compound composed mainly of carbon and a high ratio of hydrogen to oxygen is a ______. Examples include fatty acids, fats, phospholipids, steroids, and prostaglandins.
Lipid
A molecule with the chemical formula C57H110O6 is an example of which type of organic molecule?
Lipid
Hydrophobic organic molecules, such as fatty acids, fats, steroids, and prostaglandins, are classified as what type of molecule?
Lipid
Any molecule of large size and high molecular weight, such as a protein or starch, is known as a ________.
Macromolecule
Molecules like carbohydrates, proteins, and nucleic acids are examples of _______ because they are made up of many repeating subunits.
Macromolecules
Which of the following best describes denaturation?
The unfolding of a protein's three-dimensional shape
The 12 elements that together account for 0.7% of the body weight, with each accounting for no more than 0.02%, are known as ________ elements.
Trace
Which of the following terms refers specifically to an element that plays a physiological role in the body, but which accounts for less than 0.02% of the body weight?
Trace element
A lipid composed of three fatty acids joined to a glycerol is a(n) _________.
Triacylglycerol
A molecule may be composed of one element or more than one element.
True
Amino acids and other organic acids contain a carboxyl group, which can act as an acid.
True
An enzyme will usually catalyze only one step in a metabolic pathway.
True
Formation of adenosine triphosphate from adenosine diphosphate and an inorganic phosphate molecule requires the input of energy.
True
Guanosine triphosphate may serve as a source of phosphate for ATP.
True
Disaccharides are composed of how many covalently-bonded simple sugars?
Two
How many double covalent bonds are in the carbon chain of a polyunsaturated fatty acid?
Two or more
A fatty acid has a double bond in its carbon chain. It is a(n) ______ fatty acid.
Unsaturated
The concentration of an electrolyte in a body fluid is expressed as milliequivalents per liter. This is equal to the millimolar concentration of the electrolyte multiplied by the _______ of the ion.
Valence
Which of the following best describes very weak, brief attractions between neutral atoms?
Van der Waals forces
Which are examples of antioxidants?
Vitamin E Vitamin C Selenium
Hydrophilic substances are soluble in ________.
Water
Hydrophobic means that a substance is insoluble in
Water
Solvency, cohesion, adhesion, hydrogen bonding, chemical reactivity, and thermal stability are all important properties of _________ and account for its ability to support life.
Water
Which of the following is a molecule that is produced from ATP and which often serves as a second messenger?
cAMP
The amount of energy required to raise 1 g of water by 1oC is called a(n) ______.
calorie
The sodium ion (Na+) and the chloride ion (Cl-) are attracted to each other and form a(n) ______ bond.
ionic