Ch. 2 Chemistry Comes Alive Flashcards
What are the four elements that form the bulk of body matter?
Oxygen, Carbon, Hydrogen, Nitrogen
What is the definition of an atom?
The smallest unit of an element that retains the properties of that element.
Which type of chemical bond involves the sharing of electron pairs between atoms?
Covalent bond
What are the three major types of chemical reactions?
Synthesis, decomposition, and exchange
How are large organic compounds made and broken down?
Made by dehydration synthesis and broken down by hydrolysis
What is the primary function of carbohydrates in the body?
Provide an easily used energy source
What are the building blocks of proteins?
Amino acids
What is the role of ATP in cell metabolism?
Transfers energy to other compounds
What are the three types of chemical bonds?
Ionic, covalent, and hydrogen bonds
What is the main function of ATP in the cell?
Transferring energy to other compounds
What are the building blocks of carbohydrates?
Simple sugars (monosaccharides)
What is the role of enzymes in the body?
They act as catalysts to speed up chemical reactions
What is the difference between DNA and RNA?
DNA stores genetic information, while RNA helps in transmitting and expressing it
Matter
The substance of which the universe is composed
Energy
The capacity to do work or put matter into motion
Atom
The smallest unit of an element that retains the properties of that element
Isotope
Variants of a particular chemical element that differ in neutron number
Radioisotope
An isotope that has an unstable nucleus and emits radiation
Dehydration synthesis
A chemical reaction that builds up molecules by losing water molecules
Hydrolysis
A chemical process that splits a molecule by adding water
What state of matter has a definite shape and volume?
Solid
What is the main difference between mass and weight?
Mass remains constant while weight varies with gravity
What is energy defined as?
The capacity to do work or to put matter into motion
What type of energy is stored and has the potential to do work?
Potential energy
What type of energy is involved in moving matter?
Mechanical energy
What form of energy is stored in the bonds of chemical substances?
Chemical energy
What is the most useful form of energy in living systems?
Chemical energy in the form of ATP
What type of energy results from the movement of charged particles?
Electrical energy
What type of energy travels in waves and includes visible light?
Radiant energy
What are the three states of matter?
Solid, liquid, and gas.
What is kinetic energy?
Energy in action.
What is potential energy?
Stored energy that has the potential to do work.
Kinetic Energy
Energy in action.
Potential Energy
Stored energy that has the potential to do work.
What are the four elements that form the bulk of body matter?
Carbon, Oxygen, Hydrogen, Nitrogen
What is the definition of a chemical element?
A unique substance that cannot be broken down into simpler substances by ordinary chemical methods
Which subatomic particle has a positive charge?
Proton
What is the atomic number of an element?
The number of protons in its nucleus
What is the mass number of an atom?
The sum of the masses of its protons and neutrons
What is an isotope?
A structural variation of an element with the same number of protons but different numbers of neutrons
What is the primary function of oxygen in the human body?
Needed for the production of cellular energy (ATP)
What is the role of calcium in the human body?
Required for muscle contraction, conduction of nerve impulses, and blood clotting
What is the charge of a neutron?
Neutral
What is the term for the process of atomic decay in radioisotopes?
Radioactivity
Chemical element
A unique substance that cannot be broken down into simpler substances by ordinary chemical methods
Proton
A subatomic particle with a positive charge found in the nucleus of an atom
Neutron
A subatomic particle with no charge found in the nucleus of an atom
Electron
A subatomic particle with a negative charge that orbits the nucleus of an atom
Atomic mass
The sum of the masses of an atom’s protons and neutrons
What is the most abundant element in the human body by mass?
Oxygen
What is the primary function of potassium in the body?
Necessary for conduction of nerve impulses and muscle contraction
What is a molecule?
A combination of two or more atoms held together by chemical bonds
Which of the following is an example of a compound?
Water (H2O)
What type of mixture is blood?
Suspension
What is a characteristic of a solution?
The solute particles are very tiny and do not settle out.
Which of the following is a homogeneous mixture?
Air
What is the main characteristic of colloids?
They scatter light and do not settle out.
What is the concentration unit commonly used to measure blood glucose levels?
Milligrams per deciliter (mg/dl)
What is Avogadro’s number?
6.02 × 10^23
What is a sol-gel transformation?
The reversible change from a fluid (sol) state to a solid (gel) state in colloids.
What is a molecule?
A combination of two or more atoms held together by chemical bonds.
What is the difference between a compound and a mixture?
Compounds are chemically pure substances with identical molecules, while mixtures are physically intermixed substances without chemical bonding.
What is a solution?
A homogeneous mixture where the solute particles are very tiny and do not settle out.
What is a colloid?
A heterogeneous mixture with solute particles larger than those in a solution, which do not settle out but scatter light.
What is a suspension?
A heterogeneous mixture with large, often visible solutes that tend to settle out.
How can you distinguish a mixture from a compound?
Mixtures can be separated by physical means and do not involve chemical bonding, whereas compounds can only be separated by chemical means.
Solvent
The substance present in the greatest amount in a solution, usually a liquid.
Solute
A substance present in smaller amounts in a solution, dissolved in the solvent.
Molarity
A measure of concentration, defined as moles of solute per liter of solution.
Avogadro’s number
The number of particles in one mole of a substance, equal to 6.02 × 10^23.
What is the primary role of electrons in chemical bonding?
To achieve stability by filling the outermost energy level
According to the octet rule, how many electrons do atoms tend to have in their valence shell to be stable?
8
Which type of chemical bond involves the sharing of electron pairs between atoms?
Covalent bonds
What is the main characteristic of ionic bonds?
Attraction between two oppositely charged ions
Which type of bond is the weakest among the three major types of chemical bonds?
Hydrogen bonds
What type of bond forms between the oxygen atom of one water molecule and the hydrogen atom of another water molecule?
Hydrogen bond
What is the result when electrons are shared equally between atoms in a molecule?
Nonpolar molecule
Which bond type involves the complete transfer of electrons from one atom to another?
Ionic bond
What is the term for an atom’s outermost energy level that contains the chemically reactive electrons?
Valence shell
Electronegativity
The ability of an atom to attract electrons strongly.
Electropositive
Atoms with low electron-attracting ability, usually losing their valence electrons to other atoms.
What is a polar molecule?
A molecule with unequal sharing of electrons, resulting in a slight charge difference across the molecule.
What is a nonpolar molecule?
A molecule with equal sharing of electrons, resulting in no charge difference across the molecule.
What is an example of an ionic bond?
The formation of sodium chloride (NaCl) from sodium and chlorine atoms.
What is an example of a covalent bond?
The formation of a methane molecule (CH4) from carbon and hydrogen atoms.
What is an example of a hydrogen bond?
The attraction between the oxygen atom of one water molecule and the hydrogen atom of another water molecule.
What type of reaction involves the formation of a larger, more complex molecule from smaller molecules?
Synthesis reaction
What type of reaction involves breaking down a molecule into smaller molecules or constituent atoms?
Decomposition reaction
What type of reaction involves both synthesis and decomposition, where parts of the reactant molecules change partners?
Exchange reaction
What is another name for exchange reactions?
Displacement reactions
What type of reaction is characterized by the transfer of electrons between reactants?
Oxidation-reduction reaction
In a redox reaction, what is the reactant called that loses electrons?
Electron donor
In a redox reaction, what is the reactant called that gains electrons?
Electron acceptor
What is the main reason why many chemical reactions in the body are irreversible?
Energy released in the reaction is used up and products are removed from the reaction site
Which factor does NOT affect the rate of chemical reactions?
Color of reactants
What are biological catalysts called?
Enzymes
What happens to the reactant losing electrons in an oxidation-reduction reaction?
It is oxidized
What factor increases the rate of chemical reactions by increasing the kinetic energy of particles?
Higher temperatures
Oxidation
The process where a reactant loses electrons in a chemical reaction
Reduction
The process where a reactant gains electrons in a chemical reaction
What is the study of the chemical composition and reactions of living matter called?
Biochemistry
What type of compounds contain carbon and are made by living things?
Organic compounds
Which of the following is NOT considered an organic compound?
Water
Which of the following is generally defined as lacking carbon?
Inorganic compounds
Which of the following compounds contains carbon but is considered inorganic?
Carbon dioxide
What are the two major classes of chemicals in the body?
Organic and inorganic compounds.
Inorganic compounds
Compounds that generally lack carbon, including water, salts, and many acids and bases.
Why are carbon dioxide and carbon monoxide considered exceptions among inorganic compounds?
Because they contain carbon but are still classified as inorganic compounds.
Are organic or inorganic compounds more essential for life?
Both are equally essential for life.
What happens when water evaporates from the skin during sweating?
Large amounts of heat are removed from the body, providing efficient cooling.
Hydration layers
Layers of water molecules that form around large charged molecules, shielding them from other charged substances.
What role does water play in the body’s transport system?
Water acts as a solvent, dissolving nutrients, gases, and wastes for transport.
How many covalent bonds can a carbon atom form?
Four
Which type of biological molecule is typically formed by dehydration synthesis?
Polymers
What are the small, reactive parts of organic molecules called?
Functional groups
Which element is uniquely suited to form long chainlike molecules and ring structures in biological systems?
Carbon
What is released each time a monomer is added to a growing polymer chain during dehydration synthesis?
A water molecule
What is the result of adding a water molecule to each bond during hydrolysis?
Breaking the bonds and releasing monomers
Which element is central to organic molecules due to its ability to form four covalent bonds?
Carbon
What type of molecules are carbohydrates, lipids, proteins, and nucleic acids?
Organic molecules
Monomer
A small molecule that can join with others to form a polymer.
Polymer
A large molecule made up of many similar or identical monomers linked together.
What elements do carbohydrates contain?
Carbon, hydrogen, and oxygen
What is the general formula for a monosaccharide?
(CH2O)n
Which of the following is a hexose sugar?
Glucose
What is the molecular formula for glucose?
C6H12O6
Which of the following is a disaccharide?
Sucrose
What is the primary function of carbohydrates in the body?
To provide a ready, easily used source of cellular fuel
What is glycogen?
A polysaccharide consisting of a polymer of glucose molecules
Where is glycogen primarily stored in the body?
Skeletal muscle and liver cells
What process breaks down disaccharides into monosaccharides?
Hydrolysis
Which polysaccharide is the storage carbohydrate in plants?
Starch
What type of carbohydrate is glucose classified as?
Monosaccharide
What is the difference between a monosaccharide and a disaccharide?
A monosaccharide is a single sugar molecule, while a disaccharide is composed of two monosaccharides joined together.
What are the two main polysaccharides important to the body?
Starch and glycogen
What are the building blocks of triglycerides?
Fatty acids and glycerol
Which type of lipid is the major form of stored energy in the body?
Triglycerides
What is the primary function of phospholipids in the body?
Chief components of cell membranes
What is the function of cholesterol in the body?
Component of cell membranes and starting molecule for synthesis of all body steroids
Which type of lipid is involved in regulating blood pressure and promoting inflammation?
Eicosanoids
What is the role of bile salts in the digestive tract?
Help with fat digestion and absorption
What makes phospholipids ideally suited for building cellular membranes?
They have both hydrophilic and hydrophobic ends
What type of lipid is Vitamin D classified as?
Steroid
Which type of lipid is known for being a powerful vasoconstrictor?
Thromboxanes
Which lipid type includes estrogens and testosterone?
Sex hormones
What is the primary function of triglycerides in the body?
They provide stored energy and insulate body organs.
Which type of lipid is formed from interlocking hydrocarbon rings?
Steroids
What are the two types of fatty acids based on the presence of double bonds?
Saturated and unsaturated fatty acids
Which vitamins are fat-soluble?
Vitamins A, D, E, and K
Where is DNA typically found in the cell?
Nucleus
Which sugar is found in RNA?
Ribose
Which base is found in RNA but not in DNA?
Uracil
What is the structure of DNA?
Double strand coiled into a double helix
What are the building blocks of nucleic acids?
Nucleotides
Which of the following bases pair together in DNA?
Adenine and Thymine
What is the major function of RNA?
Carries out the genetic instructions for protein synthesis
What is the sugar found in DNA?
Deoxyribose
What type of bond holds the two strands of DNA together?
Hydrogen bonds
What protects cells from excessive energy release during ATP hydrolysis?
The amount of energy released corresponds closely to that needed to drive most biochemical reactions
What happens to ADP when it loses its terminal phosphate group?
It becomes adenosine monophosphate (AMP).
What type of radiation causes atoms to ionize?
Ionizing radiation
Which cells are most affected by radiation sickness?
Rapidly dividing cells
What is acidosis?
A condition of acidity or low pH (below 7.35) of the blood; high hydrogen ion concentration.
What is alkalosis?
A condition of basicity or high pH (above 7.45) of the blood; low hydrogen ion concentration.
What are heavy metals?
Metals with toxic effects on the body, including arsenic, mercury, and lead. Iron is also toxic in high concentrations.
What is ionizing radiation?
Radiation that causes atoms to ionize; for example, gamma rays and X rays.
What is radiation sickness?
Disease resulting from exposure of the body to radioactivity; rapidly dividing cells are most affected—for example, blood-forming cells and the cells lining the digestive tract.
Chemical bonds
An energy relationship holding atoms together; involves the interaction of electrons.
Sol-gel transformations
Reversible change of a colloid from a fluid (sol) to a more solid (gel) state.
Inorganic compounds
Chemical substances that do not contain carbon, including water, salts, and many acids and bases.
Adenine (ad′ĕ-nēn)
One of the two major purines found in both RNA and DNA; also found in various free nucleotides of importance to the body, such as ATP.
Endergonic reaction
Chemical reaction that absorbs energy, e.g., an anabolic reaction.
Atomic number
The number of protons in an atom.
Acidosis (as″ĭ-do′sis)
State of abnormally high hydrogen ion concentration in the extracellular fluid.
Active sites
Region on the surface of a functional (globular) protein where it binds and interacts chemically with other molecules of complementary shape and charge.
Rule of eights (ok-tet′)
The tendency of atoms to interact in such a way that they have eight electrons in their valence shell.
Alpha (α)-helix
The most common type of secondary structure of the amino acid chain in proteins; resembles a coiled spring.
Energy
The capacity to do work; may be stored (potential energy) or in action (kinetic energy).
Mechanical energy
The energy directly involved in moving matter; e.g., in bicycle riding, the legs provide the mechanical energy that moves the pedals.
Nucleus (nu′kle-is)
(1) Control center of a cell; contains genetic material; (2) clusters of neuron cell bodies in the CNS; (3) center of an atom; contains protons and neutrons.
Covalent bond (ko-va′lent)
Chemical bond created by electron sharing between atoms.
Uracil (u′rah-sil)
A smaller, single-ring base (a pyrimidine) found in RNA.
Nonpolar molecules
Electrically symmetrical molecules.
Structural proteins
Consist of extended, strandlike polypeptide chains forming a strong, ropelike structure that is linear, insoluble in water, and very stable; e.g., collagen.
Decomposition reaction
Chemical reaction in which a molecule is broken down into smaller molecules or its constituent atoms.
Dipole (polar molecule)
Nonsymmetrical molecules that contain electrically unbalanced atoms.
Avogadro’s number (av ″ o-gad′rōz)
The number of molecules in one mole of any substance, 6.02 × 1023.
Hydrophilic (hi″dro-fil′ik)
Refers to molecules, or portions of molecules, that interact with water and charged particles.
Protein (pro′tēn)
Organic compound composed of carbon, oxygen, hydrogen, and nitrogen; types include enzymes, structural components; 10–30% of cell mass.
Macromolecules
Large, complex molecules containing from 100 to over 10,000 subunits.
Double helix
The secondary structure assumed by two strands of DNA, held together throughout their length by hydrogen bonds between bases on opposite strands.
Energy level
Regions of space that consecutively surround the nucleus of an atom; the atom’s electrons are most likely to be found in these regions.
Solutes (sol′yoot)
The substance that is dissolved in a solution.
Radioactivity
The process of spontaneous decay seen in some of the heavier isotopes, during which particles or energy is emitted from the atomic nucleus; results in the atom becoming more stable.
Fatty acids
Linear chains of carbon and hydrogen atoms (hydrocarbon chains) with an organic acid group at one end. A constituent of fat.
Bicarbonate buffer system
Chemical system that helps maintain pH homeostasis of the blood. Also called carbonic acid–bicarbonate buffer system.
Kinetic energy (ki-net′ik)
The energy of motion or movement, e.g., the constant movement of atoms, or the push given to a swinging door that sets it into motion.
Molarity (mo-lar′ĭ-te)
A way to express the concentration of a solution; moles per liter of solution.
Coenzyme (ko-en′zīm)
Nonprotein substance associated with and activating an enzyme; typically a vitamin.
Displacement, reactions
Chemical reaction in which bonds are both made and broken; atoms are combined with different atoms.
Disaccharide (di-sak′ah-rīd, di-sak′ah-rid)
Literally, double sugar; e.g., sucrose, lactose.
Mass number
Sum of the number of protons and neutrons in the nucleus of an atom.
Ammonia (NH3)
Common waste product of protein breakdown in the body; a colorless volatile gas, very soluble in water and capable of acting as a weak base; a proton acceptor.
Valence shell (va′lens)
Outermost electron shell (energy level) of an atom that contains electrons.
Electrons
Negatively charged subatomic particle; orbits the atom’s nucleus.
Hydrogen ions
A hydrogen atom minus its electron and therefore carrying a positive charge (i.e., a proton).
Atomic symbol
The one- or two-letter symbol used to indicate an element; usually the first letter(s) of the element’s name.
Neutralization reaction
Displacement reaction in which mixing an acid and a base forms water and a salt.
Electron shells (energy levels)
Regions of space that consecutively surround the nucleus of an atom; the atom’s electrons are most likely to be found in these regions.
Glycogen (gli′ko-jin)
Main carbohydrate stored in animal cells; a polysaccharide.
Peptide bond (pep′tīd)
Bond joining the amine group of one amino acid to the acid carboxyl group of a second amino acid with the loss of a water molecule.
Hydrogen bonds
Weak bond in which a hydrogen atom forms a bridge between two electron-hungry atoms. An important intramolecular bond.
Cofactor
Metal ion or organic molecule that is required for enzyme activity.
Elements
One of a limited number of unique varieties of matter that composes substances of all kinds; e.g., carbon, hydrogen, oxygen.
Exergonic reactions
Chemical reaction that releases energy, e.g., a catabolic or oxidative reaction.
Synthesis
A chemical reaction in which larger, more complex atoms or molecules are formed from simpler ones.
Catalysts (kat′ah-list)
Substance that increases the rate of a chemical reaction without itself becoming chemically changed or part of the product.
Polymers
A substance of high molecular weight with long, chainlike molecules consisting of many similar (repeated) units.
Cytosine (si′to-sēn)
Nitrogen-containing base that is part of a nucleotide structure.
Chemical equilibrium
A state of apparent repose created by two reactions proceeding in opposite directions at equal speed.
Nucleic acids (nu-kle′ik)
Class of organic molecules that includes DNA and RNA.
Glycerol (glis′er-ol)
A modified simple sugar (a sugar alcohol); a building block of fats.
Octet rule (ok-tet′)
The tendency of atoms to interact in such a way that they have eight electrons in their valence shell.
Electrical energy
Energy formed by the movement of charged particles, e.g., across or along cell membranes.
Apoenzyme (ap′ō-en-zīm)
The protein portion of an enzyme.
Isotopes (i′so-tōps)
Different atomic forms of the same element, which vary only in the number of neutrons they contain; the heavier species tend to be radioactive.
Carbohydrates (kar″bo-hi′drāt)
Organic compound composed of carbon, hydrogen, and oxygen; includes starches, sugars, cellulose.
Amino acids (ah-me′no)
Organic compound containing nitrogen, carbon, hydrogen, and oxygen; building block of protein.
Activation energy
The amount of energy required to push a reactant to the level necessary for action.
Hydrophobic (hi″dro-fo′bik)
Refers to molecules, or portions of molecules, that interact only with nonpolar molecules.
Proton acceptors
A substance that takes up hydrogen ions in detectable amounts. Commonly referred to as a base.
Polysaccharides (pol″e-sak′ah-rīd)
Literally, many sugars, a polymer of linked monosaccharides; e.g., starch, glycogen.
Electromagnetic radiation
Emitted photons (wave packets) of energy, e.g., light, X ray, infrared.
Buffers
Chemical substance or system that minimizes changes in pH by releasing or binding hydrogen ions.
Cation (kat′i-on)
An ion with a positive charge.
Acids
A substance that releases hydrogen ions when in solution (compare with Base); a proton donor.
Mole (mōl)
A mole of any element or compound is equal to its atomic weight or its molecular weight (sum of atomic weights) measured in grams.
Exchange
Chemical reaction in which bonds are both made and broken; atoms are combined with different atoms.
Ionic bond (ī-ah′nik)
Chemical bond formed by electron transfer between atoms.
Monosaccharides (mon″o-sak′ah-rīd)
Literally, one sugar; building block of carbohydrates; e.g., glucose.
Dehydration synthesis
Process by which a large molecule is synthesized by removing water and covalently bonding smaller molecules together.
Chemical reaction
Process in which molecules are formed, changed, or broken down.
Atomic weight
The average of the mass numbers of all the isotopes of an element.
Reactants
A substance that is an input to a chemical reaction.
Organic compounds
Any compound composed of atoms (some of which are carbon) held together by covalent (shared electron) bonds. Examples are proteins, fats, and carbohydrates.
Polypeptide (pol″e-pep′tīd)
A chain of amino acids.
Molecule
Particle consisting of two or more atoms joined together by chemical bonds.
Thymine (thi′mēn)
Single-ring base (a pyrimidine) in DNA.
Enzymes (en′zīm)
A protein that acts as a biological catalyst to speed up a chemical reaction.
Substrate
A reactant on which an enzyme acts to cause a chemical action to proceed.
Lipids (lĭ′pid)
Hydrophobic organic compound formed of carbon, hydrogen, and oxygen; examples are fats and cholesterol.
Compound
Substance composed of two or more different elements, the atoms of which are chemically united.
Neutrons (nu′tron)
Uncharged subatomic particle; found in the atomic nucleus.
Suspensions
Heterogeneous mixtures with large, often visible solutes that tend to settle out.
Electrolytes (e-lek′tro-līt)
Chemical substances, such as salts, acids, and bases, that ionize and dissociate in water and are capable of conducting an electrical current.
Complementary bases
Refers to how a given nitrogenous base of DNA or RNA bonds to another nitrogenous base. For example, adenine (A) is the complementary base of thymine (T). The result is base pairing.
Proton donors
A substance that releases hydrogen ions in detectable amounts; an acid.
Isomers (ī′so-mer)
One of two or more substances that has the same molecular formula but with its atoms arranged differently.
Combination, reaction
A chemical reaction in which larger, more complex atoms or molecules are formed from simpler ones.
Ribonucleic acid (RNA) (ri′bo-nu-kle′ik)
Nucleic acid that contains ribose and the bases A, G, C, and U. Carries out DNA’s instructions for protein synthesis.
Triglycerides (tri-glis′er-īdz)
Fats and oils composed of fatty acids and glycerol; are the body’s most concentrated source of energy fuel.
Colloids (kol′oid)
(1) A mixture in which the solute particles (usually proteins) do not settle out readily. (2) Substance in the thyroid gland containing thyroglobulin protein.
Polar molecules
Electrically asymmetric molecules.
Chemical energy
Energy stored in the bonds of chemical substances.
Atoms
Smallest particle of an elemental substance that exhibits the properties of that element; composed of protons, neutrons, and electrons.
Phospholipids (fos″fo-lip′id)
Modified lipid, contains phosphorus.
Radioisotopes (ra″de-o-i′so-tōp)
Isotope that exhibits radioactive behavior.
Anion (an′i-on)
An ion with a negative charge.
Adenosine triphosphate (ATP) (ah-den′o-sēn tri″fos′fāt)
Organic molecule that stores and releases chemical energy for use in body cells.
Steroids (stĕ′roidz)
A class of lipids derived from (and including) cholesterol; act as hormones and as constituents of phospholipid bilayer membranes.
Hydrolysis (hi″drah′lă-sis)
Process in which water is used to split a substance into smaller parts.
Potential energy
Stored or inactive energy.
PH units (pe-āch)
The measure of the relative acidity or alkalinity of a solution.
Hydroxyl ions (hi-drok′sil)
An ion liberated when a hydroxide (a common inorganic base) is dissolved in water.
Alkalosis (al″kah-lo′sis)
State of abnormally low hydrogen ion concentration in the extracellular fluid.
Guanine (gwah′nēn)
One of two major purines occurring in all nucleic acids.
Kinetic energy (ki-net′ik)
The energy of motion or movement, e.g., the constant movement of atoms, or the push given to a swinging door that sets it into motion.
