Chapter 1: The Chemical Basis of Life Flashcards

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1
Q

Isotopes

A

Different atoms of the same element containing the same number of protons but a different number of neutrons.

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2
Q

Radioisotopes

A

Radioactive atoms of an element that spontaneously decay into smaller atoms, subatomic particles, and energy.

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3
Q

Half-Life

A

The time it takes for one-half of the nuclei in a radioactive sample to decay.

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4
Q

Radioactive Tracers

A

Radioisotopes that are used to follow chemicals through chemical reactions and trace their path as they move through the cells and bodies of organisms

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5
Q

Orbitals

A

Volumes of space around the nucleus where electrons are most likely to be found.

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6
Q

Valence Electrons

A

Electrons located in outermost s and p orbitals that determine an atom’s chemical behavior.

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7
Q

Intramolecular Forces of Attraction

A

The covalent bond that holds the atoms of a molecule together, and the ionic bond that holds ions together in a salt.

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8
Q

Electronegativity

A

A measure of an atom’s ability to attract a shared electron pair when it is participating in a covalent bond.

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9
Q

Hybridization

A

For atoms, a modification of the valence orbitals that changes the orientation of the valence electrons; in genetic coding, complementary base pairing between strands of nucleic acids via hydrogen bonding.

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10
Q

Intermolecular Bonds

A

Chemical bonds between molecules.

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11
Q

Van der Waals Forces

A

Intermolecular forces of attraction including London Forces, dipole-dipole forces and hydrogen bonds.

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12
Q

Miscible

A

Describes liquids that dissolve into one another.

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13
Q

Immiscible

A

Describes liquids that form separate liquids instead of dissolving.

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14
Q

Hydrophobic

A

Having an aversion to water; the tendancy of nonpolar molecules to exclude water.

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15
Q

Hydrophilic

A

Having an affinity to water; the tendency of polar and ionic substances to dissolve in water.

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16
Q

Neutralization Reaction

A

The reaction of an acid and a base to produce water and salt.

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17
Q

Strong Acids

A

Acids that ionize completely in aqueous solution.

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18
Q

Strong Bases

A

Bases that ionize completely in aqueous solution.

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19
Q

Weak Acids

A

Acids that partially ionize in aqueous solution.

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20
Q

Weak Bases

A

Bases that partially ionize in aqueous solution.

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21
Q

Equilibrium

A

A condition in which opposing reactions occur at equal rates.

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22
Q

Buffers

A

Chemical systems containing a substance that can donate H+ ions when they are required and containing a substance that can remove H+ ions when there are too many in a solution.

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23
Q

Activation Energy

A

The difference between the energy level of the transition state and the potential energy of reacting molecules.

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24
Q

Activator

A

A substance that binds to an allosteric site on an enzyme and stabilizes the protein conformation that keeps all the active site available to their substrates.

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25
Q

Active Site

A

The location where the substrate binds to an enzyme.

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26
Q

Adenosine Triphosphate (ATP)

A

A nucleotide derivative that acts as the primary energy-transferring molecule in living organisms.

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27
Q

Allosteric Inhibitor

A

A substance that binds to an allosteric site on an enzyme and stabilizes the inactive form of the enzyme.

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28
Q

Allosteric Sites

A

Receptor sites, some distance from the active site of certain enzymes, that bind substances that may inhibit or stimulate an enzyme’s activity.

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29
Q

Alpha (α) Helix

A

A type of polypeptide secondary structure characterized by a tight coil that is stabilized by hydrogen bonds.

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30
Q

Amino Terminus

A

The free amino group at one end of a polypeptide.

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31
Q

Anabolic Reactions

A

Reactions that produce large molecules from smaller subunits.

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32
Q

Antiparallel

A

Describes two adjacent nucleotides running in opposite directions relative to one another.

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33
Q

β-pleated sheet

A

Polypeptide secondary structures that form between parallel stretches of a polypeptide and are stabilized by hydrogen bonds.

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34
Q

Bond Energy

A

The minimum energy required to break one mole of bonds between two species of atoms; a measure of the stability of a chemical bond.

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35
Q

Bonding Capacity

A

The number of covalent bonds an atom can form with neighbouring atoms.

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36
Q

Carboxyl Terminus

A

The free carboxyl group at one end of a polypeptide.

37
Q

Catabolic Reactions

A

Reactions that break macromolecules into their individual subunits.

38
Q

Chaperone Proteins

A

Special proteins that aid a growing polypeptide to fold into tertiary structure.

39
Q

Coenzymes

A

Organic nonprotein cofactors that are needed for some enzymes to function.

40
Q

Cofactors

A

Nonprotein components, such as dissolved ions, that are needed for some enzymes to function.

41
Q

Competitive Inhibitors

A

Substances that compete with the substrate for an enzyme’s active site.

42
Q

Condensation Reaction

dehydration synthesis

A

A reaction that creates a covalent bond between two interacting subunits,linking them to each other.

43
Q

Conformation

A

The three-dimensional shape of a protein determined by the sequence of amino acids it contains.

44
Q

Disulfide Bridge

A

Covalent bonds between cysteine residues in a polypeptide that stabilize tertiary structure.

45
Q

Endergonic Reaction

A

A chemical reaction in which the energy of the products is more than the energy of the reactants; chemists call it an endothermic reaction.

46
Q

Energy

A

The ability to do work.

47
Q

Entropy

A

A measure of the randomness or disorder in a collection of objects or energy; symbolized by S.

48
Q

Enzyme–Substrate Complex

A

An enzyme with its substrate attached to the active site.

49
Q

Essential Amino Acids

A

Amino acids that the body cannot synthesize from simpler compounds; they must be obtained from the diet.

50
Q

Ester Linkage

A

A functional group linkage formed by the condensation of a carboxyl group and a hydroxyl group.

51
Q

Exergonic Reaction

A

A chemical reaction in which the energy of the products is less than the energy of the reactants; chemists call it an exothermic reaction.

52
Q

Feedback Inhibition

A

A method of metabolic control in which a product formed later in a sequence of reactions allosterically inhibits an enzyme that catalyzes a reaction occurring earlier in the process.

53
Q
Free Energy (Gibbs free
energy)
A

Energy that can do useful work.

54
Q

Functional Groups

A

Reactive clusters of atoms attached to the carbon backbone of organic molecules.

55
Q

Globular Proteins

A

Protein molecules composed of one or more polypeptide chains that take on a rounded,spherical shape.

56
Q

Glycosidic Linkages

A

Covalent bonds holding monosaccharides to one another that are formed by condensation reactions in which the H atom comes from a hydroxyl group of one sugar and the —OH group comes from a hydroxyl group of the other.

57
Q

Hydrolysis Reaction

A

A catabolic reaction in which a water molecule is used to break a covalent bond holding subunits together.

58
Q

Induced-fit Model

A

A model of enzyme activity that describes an enzyme as a dynamic protein molecule that changes shape to better accommodate the substrate.

59
Q

Isomers

A

Molecules with the same chemical formula but with a different arrangement of atoms.

60
Q

Kinetic Energy

A

Energy possessed by moving objects.

61
Q

Macromolecules

A

Large molecules sometimes composed of a large number of repeating subunit.

62
Q

Metabolism

A

The sum of all anabolic and catabolic processes in a cell or organism.

63
Q

Micelles

A

Spheres formed when phospholipids are added to water.

64
Q

Noncompetitive Inhibitors

A

Substances that attach to a binding site on an enzyme other than the active site,causing a change in the enzyme’s shape and a loss of affinity for its substrate.

65
Q

Oligosaccharides

A

Sugars containing several simple sugars attached to one another.

66
Q

Oxidation

A

A chemical reaction in which an atom loses one or more electrons.

67
Q

Oxidizing Agent

A

The substance that gains an electron in a redox reaction; the substance that causes the oxidized atom to become oxidized.

68
Q

Peptide Bonds

A

The amide linkage that holds amino acids together in polypeptides.

69
Q

Phosphorylation

A

The process of attaching a phosphate group to an organic molecule.

70
Q

Potential Energy

A

Energy stored by virtue of an object’s position within an attractive or repulsive force field.

71
Q

Potential Energy Diagram

A

A diagram showing the changes in potential energy that take place during a chemical reaction.

72
Q

Primary Structure

A

The unique sequence of amino acids in a polypeptide chain.

73
Q

Quaternary Structure

A

Two or more polypeptide subunits forming a functional protein.

74
Q

Redox Reaction

A

A chemical reaction involving the transfer of one or more electrons from one atom to another; a reaction in which oxidation and reduction occur.

75
Q

Reducing Agent

A

The substance that loses an electron in a redox reaction; the substance that causes the reduced atom to become reduced.

76
Q

Reduction

A

A chemical reaction in which an atom gains one or more electrons.

77
Q

Residue

A

An amino acid subunit of a polypeptide.

78
Q

Secondary Structure

A

Coils and folds in a polypeptide caused by hydrogen bonds between hydrogen and oxygen atoms near the peptide bonds.

79
Q

Strand

A

A single nucleotide polymer.

80
Q

Substrate

A

The reactant that an enzyme acts on when it catalyzes a chemical reaction.

81
Q

Tertiary Structure

A

Supercoiling of a polypeptide that is stabilized by side-chain interactions,including covalent bonds, such as disulfide bridges.

82
Q

Transition State

A

In a chemical reaction,a temporary condition in which the bonds within reactants are breaking and the bonds between products are forming.

83
Q

Triacylglycerols (triglycerides)

A

Lipids containing three fatty acids attached to a single molecule of glycerol.

84
Q

Van der Waals Forces

A

Intermolecular forces of attraction including London forces,dipole–dipole forces,and hydrogen bonds.

85
Q

Valence Shell Electron

A

Electrons located in outermost s and p orbitals that determine an atom’s chemical behaviour.

86
Q

Valence Shell Electron Pair Repulsion (VSEPR) theory

A

A method for predicting molecular shape based on the mutual repulsion of valence electron pairs.

87
Q

Work

A

The transfer of energy from one body or place to another.

88
Q

C = O

A

Carbonyl Group