| Term | Definition |
|---|---|
| adhesion | The attractive force between water molecules and other polar substances, allowing water to stick to different surfaces. |
| cohesion | The attractive force between water molecules that causes them to stick together, resulting from hydrogen bonding. |
| evaporative cooling | The process by which the evaporation of water removes heat from an organism or environment. |
| heat of vaporization | The energy required to convert a liquid to a gas, enabling water to remove heat from organisms through evaporative cooling. |
| homeostasis | The maintenance of stable internal environmental conditions in an organism despite external and internal changes. |
| hydrogen bond | Weak attractive forces between a hydrogen atom bonded to an electronegative atom and another electronegative atom, occurring between or within biological molecules. |
| polar covalent bonds | Chemical bonds between atoms where electrons are unequally shared, resulting in partial positive and negative charges. |
| polarity | The unequal distribution of electrical charge in a molecule, resulting in one end being partially positive and the other partially negative. |
| specific heat capacity | The amount of energy required to raise the temperature of a substance by one degree, allowing water to resist rapid temperature changes. |
| surface tension | The property of water that allows its surface to resist breaking, resulting from hydrogen bonding between adjacent water molecules. |
| Term | Definition |
|---|---|
| carbohydrates | Biological molecules composed of carbon, hydrogen, and oxygen that serve as a primary source of energy and structural support in living organisms. |
| carbon | An element that is the most prevalent component of biological molecules and forms the backbone of all organic compounds. |
| hydrogen | An element that is a prevalent component of biological molecules and is bonded to carbon, oxygen, and nitrogen in macromolecules. |
| lipid | Hydrophobic or amphipathic biological molecules composed primarily of carbon, hydrogen, and oxygen that store energy and form cell membranes. |
| macromolecules | Large, complex molecules composed of many atoms that are essential for life processes, including carbohydrates, proteins, lipids, and nucleic acids. |
| nitrogen | An element used in the building of nucleic acids and proteins as part of amino groups and nitrogenous bases. |
| nucleic acid | Macromolecules composed of nucleotides containing carbon, hydrogen, oxygen, nitrogen, and phosphorus that store and transmit genetic information. |
| oxygen | An element that is a prevalent component of biological molecules and is found in carbohydrates, lipids, proteins, and nucleic acids. |
| phospholipid | Amphipathic molecules with hydrophilic phosphate heads and hydrophobic fatty acid tails that form the basic structure of the cell membrane. |
| phosphorus | An element used in the building of phospholipids and nucleic acids, particularly in phosphate groups. |
| protein | Macromolecules composed of amino acids linked together, containing carbon, hydrogen, oxygen, nitrogen, and often sulfur, that perform diverse functions in cells. |
| sulfur | An element used in the building of proteins, often found in disulfide bonds between amino acids. |
| Term | Definition |
|---|---|
| covalent bond | Chemical bonds formed by the sharing of electrons between atoms, which can be broken or formed during macromolecule reactions. |
| dehydration synthesis | A chemical reaction that joins two smaller molecules together through covalent bonding by removing water, resulting in the formation of a larger molecule. |
| hydrolysis | A chemical reaction that breaks down molecules by cleaving covalent bonds through the addition of water, splitting polymers into smaller monomers. |
| monomer | Small individual molecules that serve as the building blocks for larger polymers. |
| polymer | A large molecule composed of many monomers linked together through covalent bonds. |
| polymerization | The process by which many monomers are connected together to form a polymer. |
| Term | Definition |
|---|---|
| cellulose | A polysaccharide polymer composed of glucose monomers that provides structural support in plant cell walls. |
| covalent bond | Chemical bonds formed by the sharing of electrons between atoms, which can be broken or formed during macromolecule reactions. |
| glycogen | A polysaccharide polymer that serves as an energy storage molecule in animals. |
| monomer | Small individual molecules that serve as the building blocks for larger polymers. |
| monosaccharides | Simple sugars that serve as monomers (building blocks) for polysaccharides and carbohydrates. |
| polymer | A large molecule composed of many monomers linked together through covalent bonds. |
| polysaccharides | Complex carbohydrates formed by linking many monosaccharide monomers together through covalent bonds. |
| starch | A polysaccharide polymer that serves as an energy storage molecule in plants. |
| Term | Definition |
|---|---|
| cholesterol | A steroid molecule found in the plasma membranes of vertebrate animals that regulates membrane fluidity and stability. |
| fats | Lipids composed of glycerol and fatty acids that provide energy storage, support cell function, and can provide insulation in mammals. |
| fatty acid | Organic compounds consisting of a carboxyl group attached to a long hydrocarbon chain; can be saturated or unsaturated. |
| hydrophobic | Water-repelling; referring to nonpolar molecules or regions that do not interact favorably with water. |
| lipid | Hydrophobic or amphipathic biological molecules composed primarily of carbon, hydrogen, and oxygen that store energy and form cell membranes. |
| lipid bilayer | A double layer of phospholipids that forms the basic structure of cell membranes and plasma membranes. |
| nonpolar | Referring to molecules or groups with even distribution of electrical charge, making them hydrophobic. |
| phospholipid | Amphipathic molecules with hydrophilic phosphate heads and hydrophobic fatty acid tails that form the basic structure of the cell membrane. |
| plasma membrane | The selectively permeable membrane that surrounds the cell, composed of phospholipids, proteins, and other molecules that regulate what enters and exits the cell. |
| saturated fatty acid | Fatty acids that contain only single bonds between carbon atoms. |
| steroid | Lipids with a four-ring carbon structure that function as hormones supporting growth, development, energy metabolism, and homeostasis. |
| unsaturated fatty acid | Fatty acids that contain at least one double bond between carbon atoms, causing the carbon chain to kink. |
| Term | Definition |
|---|---|
| 3' end | The end of a nucleic acid strand defined by the three prime hydroxyl group of the sugar. |
| 5' end | The end of a nucleic acid strand defined by the five prime phosphate group of the sugar. |
| adenine | A purine nitrogenous base found in both DNA and RNA that pairs with thymine in DNA or uracil in RNA. |
| antiparallel | The orientation of the two DNA strands running in opposite directions, with one strand oriented 5' to 3' and the other 3' to 5'. |
| base pairing | The specific pairing of nitrogenous bases between DNA strands (A-T and C-G) or in RNA (A-U). |
| covalent bond | Chemical bonds formed by the sharing of electrons between atoms, which can be broken or formed during macromolecule reactions. |
| cytosine | A pyrimidine nitrogenous base found in both DNA and RNA that pairs with guanine. |
| deoxyribose | A five-carbon sugar found in DNA nucleotides. |
| DNA | Deoxyribonucleic acid; a double-stranded nucleic acid that stores genetic information using deoxyribose sugar and thymine as a nitrogenous base. |
| double helix | The three-dimensional structure of DNA consisting of two antiparallel strands twisted around each other. |
| guanine | A purine nitrogenous base found in both DNA and RNA that pairs with cytosine. |
| hydrogen bond | Weak attractive forces between a hydrogen atom bonded to an electronegative atom and another electronegative atom, occurring between or within biological molecules. |
| nitrogenous base | A nitrogen-containing molecule that is part of a nucleotide; includes adenine, thymine, guanine, cytosine, and uracil. |
| nucleic acid | Macromolecules composed of nucleotides containing carbon, hydrogen, oxygen, nitrogen, and phosphorus that store and transmit genetic information. |
| nucleotide | The monomer unit of nucleic acids, consisting of a five-carbon sugar, a phosphate group, and a nitrogenous base. |
| phosphate | A chemical group that is part of the nucleotide structure and forms covalent bonds between nucleotides in a nucleic acid strand. |
| ribose | A five-carbon sugar found in RNA nucleotides. |
| RNA | Ribonucleic acid; typically a single-stranded nucleic acid that uses ribose sugar and uracil as a nitrogenous base. |
| thymine | A pyrimidine nitrogenous base found in DNA that pairs with adenine. |
| uracil | A pyrimidine nitrogenous base found in RNA that pairs with adenine. |
| Term | Definition |
|---|---|
| alpha-helix | A coiled secondary structure of a protein formed by hydrogen bonding between backbone atoms of the polypeptide chain. |
| amino acid | Organic molecules that serve as the building blocks of proteins, each composed of a central carbon atom bonded to a hydrogen atom, a carboxyl group, an amine group, and a variable R group. |
| beta-pleated sheet | An extended secondary structure of a protein formed by hydrogen bonding between backbone atoms of the polypeptide chain, creating a zigzag pattern. |
| disulfide bridge | Covalent bonds formed between sulfur atoms in cysteine R groups that stabilize tertiary protein structure. |
| hydrogen bond | Weak attractive forces between a hydrogen atom bonded to an electronegative atom and another electronegative atom, occurring between or within biological molecules. |
| hydrophobic interaction | Interactions between nonpolar R groups that cluster together in the interior of a protein to avoid contact with water, contributing to tertiary structure. |
| ionic interaction | Electrostatic attractions between oppositely charged R groups that stabilize tertiary protein structure. |
| peptide bond | Covalent bonds formed between the carboxyl group of one amino acid and the amine group of another amino acid, linking amino acids together in a protein chain. |
| polypeptide | A chain of amino acids linked together by peptide bonds. |
| primary structure | The linear sequence of amino acids in a polypeptide chain, determined by the specific order of amino acids in the protein. |
| quaternary structure | The arrangement and interactions of multiple polypeptide chains within a protein complex. |
| R group | The variable side chain of an amino acid that determines its chemical properties (hydrophobic/nonpolar, hydrophilic/polar, or ionic) and influences protein structure and function. |
| secondary structure | Local folding patterns in a protein formed by hydrogen bonding between atoms of the polypeptide backbone, including alpha-helices and beta-pleated sheets. |
| tertiary structure | The three-dimensional shape of a protein resulting from interactions such as hydrogen bonds, hydrophobic interactions, ionic interactions, and disulfide bridges between R groups. |