Biochemistry Chp. 1 Flashcards
Isotope
A form of an element that differs in its numbers of neutrons
Radioisotope
A radioactive isotope of an element
Orbital
A region of space that is occupied by electrons located around the nucleus of an atom
Valence electrons
An electron in the outermost energy level or shell of an atom
Ionic bond
A bond that results from the attraction between two oppositely charged atoms or molecules
Cation
An ion that has a positive charge
Anion
An ion that has a negative charge
Polar covalent bond
A bond between two atoms, made up of unequally shared electrons
Intermolecular force
The force of attraction between two molecules
Polarity
Partial positive or negative charge at the ends of a molecule
Van der Waals forces
Very weak attractions between two molecules, or parts of molecules, when they are close together
Hydrogen bond
The attractive force between a partially positively charged hydrogen atom and a partially negatively charged atom in another molecule
Dehydration reaction
A chemical reaction in which submits of a larger molecule are joined by the removal of water; also called a condensation reaction
Hydrolysis reaction
A chemical reaction in which water is used as a reactant to split a larger molecule into smaller subunits
Neutralization reaction
A reaction in which an acid and a base combine to create a salt and water
Redox reaction
An electron transfer reaction
Oxidation
A reaction in which a molecule loses electrons
Reduction
A reaction in which a molecule gains electrons
Specific heat
The amount of thermal energy required to raise the temperature of a given quantity of a substance by 1 degrees Celusis
Cohesion
Water molecules form hydrogen bonds with each other (stick together)
Surface tension
Measure of how difficult it is to stretch or break the surface of a liquid (water is pulled together creating the smallest surface area possible)
Adhesion
Water molecules form hydrogen bonds with other polar molecules
Buffer
A chemical that compensates for pH changes in a solution by accepting or donating H+ ions
Hydrophilic molecules
Polar or charged molecules that are strongly attracted to water
Hydrophobic molecules
Non-polar molecules that are not strongly attracted to water
Autoionization
The process in which a molecule spontaneously dissociates into ions
Strong acid
Completely dissociates into an aqueous solution, for example HCI
Strong base
Completely dissociates into an aqueous solution, for example NaOH
Weak acid
Only partially ionizes in water, for example acetic acid (1.3%)
Weak base
Only partially ionizes in water, for example ammonia (10%)
Neutralization reaction
When an acid and base react with one another to form neutral products, which are water and a salt
Functional groups
A group of atoms that affects the function of a molecule by participating in chemical reactions
Carbohydrate
A biomolecule that consists of carbon, oxygen, and hydrogen
Monosaccharide
The simplest form of a carbohydrate, consisting of a single sugar unit; a building block for more complex carbohydrates (ex. glucose and fructose)
Isomer
A molecule that has the same composition as another, but a different arrangement of atoms
Ex. glucose, fructose, and galactose
Disaccharide
A carbohydrate molecule that is made from two monosaccharide units (ex. maltose and lactose)
Glycosidic bond
A bond between two monosaccharides
Complex carbohydrate
A molecule that is composed of hundreds to thousands of monosaccharides linked together; an essential part of nutrition and a valuable energy source
Polysaccharide molecule
A molecule that contains many linked monosaccharides (three or more - ex. starch or cellulose)
Polymerization
A process in which small subunits are linked to form a large molecule
Monomer
A small molecule that can bind chemically to other molecules
Polymer
A large molecule that is formed when monomers link together chemically in a chain
Lipid
A nonpolar compound that is made mostly of carbon and hydrogen
Fatty acid
A molecule that consists of a carboxyl group and hydrocarbon chain.
Triglyceride
A fat; three fatty acid chains linked to a glycerol molecule
Saturated fat
A lipid that is composed of saturated fatty acids with single bonds in their hydrocarbon chain
Unsaturated fat
A lipid that is composed of unsaturated fatty acids with double bonds in their hydrocarbon chain
Phospholipid
A lipid that consists of two fatty acids and a phosphate group bound to glycerol
Steroid
A lipid that is composed of four carbon rings
Wax
A lipid that is formed when long fatty acid chains are joined to alcohols or carbon rings
Protein
A large molecule that consists of many amino acid subunits that are joined together by peptide bonds folded into a specific three-dimensional shape
Nucleic acid
A blueprint for proteins that are synthesized in cells; stores hereditary information
Amino acid
A molecule that contains a carboxyl group and an amino group; serves as the monomer subunit of proteins
Peptide bond
A covalent bond that links amino acids
Peptide
A chain of amino acid subunits that are connected by peptide bonds
Polypeptide
A peptide with more than 50 amino acids
Denaturation
The loss of both the structure and function of a protein
Nucleotide
The building block of nucleic acids; consists of a 5-carbon sugar, a nitrogenous base, and one to three phosphate groups
Phosphodiester bond
A link that is formed between nucleotides by a phosphate bridge
Antiparallel
Oriented in opposite directions
Enzyme
A biological catalyst, usually a protein, that speeds up a chemical reaction
Substrate
A substance that is recognized by and binds to an enzyme
Active site
A pocket or groove in an enzyme that binds its substrate
Induced fit model
A model of enzyme activity that describes how an enzyme changes shape to better accommodate a substrate
Cofactor
A non-protein group that binds to an enzyme and is essential for catalytic activity
Coenzyme
An organic molecule that acts as a cofactor of an enzyme
Competitive inhibition
A situation in which a competitor substance binds to a normal substrate binding site to block enzyme activity
Noncompetitive inhibition
A situation in which molecules bind to an enzyme at a site that is not the active site, thus blocking enzyme activity
Allosteric site
A binding site on an enzyme that binds regulatory molecules
Feedback inhibition
The regulation of a pathway by one of the products of this pathway
Valence
The number of chemical bonds an element is capable of forming (ex. carbon can form four)
Chemical formula
A symbolic representation of an element or compound
(ex. NaCl -table salt). Use subscripts and parentheses to denote the number of atoms in a molecule of the substanc
Glucose
A monosaccharide with the chemical formula
C6H12O6. Glucose is the primary molecule used during cellular respiration reaction
Fibrous protein
Long, linear, and narrow proteins that provides strength (repetitive amino acid sequence)
Ex. silk, collagen, and keratin
Globular protein
Compact, round, and spherical proteins that are good for transport (irrepetitive amino acid sequence - tertiary)
Ex. hemoglobin
Protein prosthetic groups
A non-protein component that is required for proteins to function
Ex. Oxygen is bound to four heme groups in hemoglobin which are held by polypeptides
Catabolic reaction (pathway)
A pathway in which energy is released and complex molecules are broken down into simple molecules
Ex. cellular respiration
Anabolic reaction (pathway)
A pathway in which energy is supplied to build complex molecules from simple molecules
Ex. photosynthesis or the synthesis of proteins and nucleic acids
