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39 terms

ch 6 Chemistry in Biology

vocabulary terms for McGraw-Hill Biology ch 6 Chemistry in Biology
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atom
the building blocks of matter
nucleus
the center of the atom, contains protons and neutrons
proton
positively charged particles in the atom
neutron
particles that have a neutral charge
electron
negatively charged particles
element
pure substance of only one kind of atom, it cannot be broken down into simpler substances by chemical or physical means
isotope
atoms of the same element that have different number of neutrons
compound
a pure substance formed when two or more different elements combine.
covalent bond
formed when atoms share electrons
molecule
a compound formed when atoms are held together by covalent bonds
ion
an atom that has lost or gained electrons, can be + or -
ionic bond
formed when atoms transfer electrons from a metal to a nonmetal, is an electrical attraction between two oppositely charged atoms or groups of atoms
Van der Waals forces
attractive forces between positive and negative regions and pull on the molecules to hold them together
chemical reaction
process by which atoms or substances are reorganized into different substances
reactants
substances that enter into a chemical reaction, often found on the left side of the arrow
products
substances that are formed from a chemical reaction, often found on the right side of the arrow
activation energy
minimum energy needed for reactants to form a product
catalyst
a substance that lowers the activation energy needed to start a chemical reaction
enzyme
special proteins that act like a biological catalyst, they speed up the chemical reaction by lowering the activation energy needed to start the reaction
substrate
the reactants that bind to the enzyme
active site
the specific location where a substrate binds on an enzyme
polar molecule
molecules that have an unequal distribution of charges, water is an example
hydrogen bond
the weak interaction between two different atoms, a weak electrostatic bond formed by the attraction of opposite charges - water molecules are held together by this
mixture
combination of two or more substances in which each substance retains its individual characteristics and properties
solution
another name for a homogeneous mixture, when a mixture has a uniform composition throughout
solvent
a substance in which another substance is dissolved within when a solution is formed, water is the world's universal __________.
solute
the substance that is dissolved in the solvent when a solution is formed
acids
substance that releases hydrogen ions (H+) when dissolved in water, has a pH of less than 7
bases
substance that releases hydroxide ions (OH-) when dissolved in water, has a pH of greater than 7
pH
the measure of the concentration of hydrogen ions (H+) in a solution
buffer
mixtures that can react with acids or bases to keep the pH within a particular range
macromolecule
large molecules that are formed by joining smaller organic molecules together
polymer
molecules that are made from repeating units of identical or nearly identical compounds
carbohydrate
compounds composed of carbon, hydrogen and oxygen in a ratio of one oxygen and two hydrogen atoms for each carbon atom - can be an energy source and/or provide structural support in cell walls as cellulose
lipid
molecules that are made mostly of carbon and hydrogen, make up fats, oils and waxes - primary function is to store energy
protein
compound that is made of small carbon compounds called amino acids which are joined together by peptide bonds - primary building blocks of organisms
amino acid
small compounds that are made of carbon, nitrogen, oxygen, hydrogen and sometimes sulfur - they all share the same general structure - there are twenty different kinds in organisms.
nucleic acid
complex macromolecules that store and transmit genetic information, found in each of our cells as DNA or RNA
nucleotide
smaller repeating subunits of nucleic acids formed from a simple sugar, phosphate group, and a nitrogen -containing base