Chapter 2 Test Bank

A comprehensive set of flashcards covering key concepts, definitions, and terminology from Chapter 2 in preparation for an exam in chemistry and biology.

Chemistry

The branch of science that deals with the composition of matter.

Matter

Anything that has weight and takes up space.

Mass number

The sum of the number of protons and neutrons in an atom's nucleus.

Sodium ion

An ion that carries a positive charge due to the loss of an electron.

Chloride ion

An ion that carries a negative charge due to the gain of an electron.

Covalent bond

A bond formed when two atoms share electrons.

Molecular formula

A representation that indicates the number and types of atoms in a molecule.

Double covalent bond

A chemical bond in which two pairs of electrons are shared between two atoms.

Compound

A substance formed when two or more different elements are chemically bonded together.

Exchange reaction

A reaction in which the bonds of a reactant molecule break and simpler molecules or ions are formed.

Synthesis reaction

A reaction that occurs when two or more reactants combine to form a more complex product.

pH value

A measure of hydrogen ion concentration in solutions.

Acid

A substance that releases hydrogen ions when dissolved in water.

Base

A substance that releases hydroxide ions in water.

Buffer

A chemical that helps resist changes in pH in a solution.

Salt

A compound made of oppositely charged ions.

Oxygen

A necessary element for cells to release energy from glucose.

Triglyceride

A lipid made up of glycerol and three fatty acids.

Cholesterol

A type of lipid known as a steroid, not protein.

Steroid

Lipid molecules consisting of four connected carbon rings.

Amino acids

The building blocks of proteins.

DNA

A type of nucleic acid that contains the genetic instructions for the development of living things.

RNA

A type of nucleic acid involved in protein synthesis.

Atoms

The smallest units of matter that retain the properties of an element.

Protons

Positively charged particles in an atom's nucleus.

Electrons

Negatively charged particles that orbit an atom's nucleus.

Isotopes

Atoms of the same element that have different numbers of neutrons.

Hydrogen ions

Positively charged ions created when acids dissociate in solution.

Inorganic substances

Compounds that lack carbon-hydrogen bonds.

Organic substances

Compounds that contain carbon and are typically formed by living organisms.

Chemical bond

The attraction between atoms that allows the formation of chemical substances.

Ionic bond

A bond formed between ions with opposite charges.

Hydrogen bond

A weak bond between a hydrogen atom and an electronegative atom.

Electron shells

The regions around an atom's nucleus where electrons are located.

Atomic number

The number of protons in the nucleus of an atom.

Mass number

The total number of protons and neutrons in an atom's nucleus.

Nucleus

The central part of an atom that contains protons and neutrons.

Hydrophilic

Substances that are attracted to water.

Hydrophobic

Substances that repel water.

Hydroxide ions

Negatively charged ions that increase in concentration in basic solutions.

Concentration

The amount of a substance in a given volume.

Organic compound

A compound that primarily contains carbon and is typically found in living organisms.

Polysaccharides

Long chains of monosaccharides; include starches.

Disaccharides

Sugars formed from two monosaccharides.

Monosaccharides

The simplest form of carbohydrates; simple sugars.

Triglycerides

Fats consisting of three fatty acids and glycerol.

Phospholipids

Lipids with a hydrophilic head and two hydrophobic tails, important for cell membranes.

Steroids

Lipid-based molecules that have four carbon rings.

Carbohydrates

Organic compounds made of carbon, hydrogen, and oxygen; primary function is energy.

Proteins

Organic compounds made of amino acids that perform a variety of functions in the body.

Electrolytes

Ionic compounds that dissociate in water and conduct electricity.

Neutrons

Neutral particles located in an atom's nucleus.

Molecule

Two or more atoms chemically bonded together.

Chemical reaction

A process that leads to a change in the composition of matter.

Simple sugars

Another term for monosaccharides.

Amino group

A functional group consisting of a nitrogen atom bonded to two hydrogen atoms.

Carboxyl group

A functional group consisting of a carbon atom double bonded to an oxygen atom and also bonded to a hydroxyl group.

R group

The side chain or functional group of an amino acid that distinguishes it from others.

Catalyst

A substance that increases the rate of a reaction without being consumed.

Enzyme

A biological catalyst that speeds up biochemical reactions.

Antibody

A protein produced by the immune system to identify and neutralize foreign objects.

Receptor

A protein that binds to signaling molecules and initiates a response.

Primary structure

The sequence of amino acids in a polypeptide.

Secondary structure

The folding or coiling of the polypeptide chain stabilized by hydrogen bonds.

Tertiary structure

The three-dimensional structure of a polypeptide.

Quaternary structure

The structure that results from the association of two or more polypeptide chains.

Protein denaturation

The alteration of a protein’s structure leading to a loss of function.

Nucleotide

A building block of nucleic acids, consisting of a nitrogenous base, a sugar, and a phosphate group.

Hydrogen bonding

A type of weak chemical bond that involves a hydrogen atom and an electronegative atom.

DNA structure

The double helix formed by two strands of nucleotides held together by hydrogen bonds.

RNA structure

Typically single-stranded nucleic acid involved in protein synthesis.

Peptide bond

The bond that links amino acids together in proteins.

Energy in chemical reactions

The capacity to perform work in chemical transformations.

Hydrophobic interactions

Interactions that occur between nonpolar substances in water.

Signal transduction

The process by which a cell responds to substances outside its membrane.

Activation energy

The energy needed to initiate a chemical reaction.

Solvent

A substance that dissolves a solute, resulting in a solution.

Solute

A substance that is dissolved in a solvent.

Physiology

The branch of biology that deals with the normal functions of living organisms.

Homeostasis

The maintenance of stable internal conditions in an organism.

Electrons in bonding

Electrons that are involved in forming chemical bonds.

Atomic structure

The arrangement of protons, neutrons, and electrons in an atom.

Hydrogen ion concentration

The number of hydrogen ions present in a solution affecting its acidity.

Acid-base balance

The equilibrium between acid and base concentrations in body fluids.

Cell membranes

Barrier that protects the cell and regulates what enters and leaves.

Active transport

Energy-requiring process that moves substances against their concentration gradient.

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

Facilitated diffusion

Passive transport that relies on transport proteins to move substances across a membrane.

Osmosis

The diffusion of water through a selectively permeable membrane.

Homeostatic mechanisms

Processes that help maintain balance in body systems.

Feedback loops

Mechanisms that maintain homeostasis by either enhancing or reducing changes in conditions.

Chemical equilibrium

A state where the rate of the forward reaction equals the rate of the reverse reaction.

Polar molecules

Molecules that have a partial positive charge on one end and a partial negative charge on the other end.

Nonpolar molecules

Molecules that do not have charged regions.

Hydrophilic substances

Substances that interact well with water.

Hydrophobic substances

Substances that do not mix well with water.

Nucleotide structure

A nucleotide consists of a sugar, phosphate group, and nitrogenous base.

Electrolyte balance

The balance between positive and negative ions in body fluids.

Metabolism

The sum of all chemical processes that occur in the body.

Catabolism

The breakdown of complex molecules into simpler ones.