Water, Macromolecules, and Nucleic Acids - Vocabulary Flashcards

Vocabulary flashcards covering key terms and definitions from water properties, macromolecules, and nucleic acids from the notes.

Polar covalent bond

A covalent bond where electrons are shared unequally, creating partial charges within a molecule (as in the O–H bonds of water).

Water polarity

A property of water due to unequal electron sharing, giving partial positive charges on H and partial negative on O, enabling hydrogen bonding.

Hydrogen bond

A weak attraction between a hydrogen atom on one molecule and a highly electronegative atom (like O or N) on another or within a molecule.

Cohesion

Attraction between like molecules, such as water–water, due to hydrogen bonding.

Adhesion

Attraction between water and nonwater substances, aiding movement of water along surfaces.

Surface tension

The cohesive force at a liquid’s surface that makes it behave as if covered with a stretched film.

Specific heat capacity

The amount of heat required to raise the temperature of a substance; water has a high value, helping stable body temperatures.

Heat of vaporization

The energy required to convert a liquid to vapor; water’s high value enables evaporative cooling.

Evaporative cooling

Cooling that occurs when liquid water evaporates, removing heat as it changes to gas.

Capillary action

The upward or lateral movement of water in narrow spaces due to cohesion and adhesion.

Homeostasis

Maintenance of stable internal conditions in living organisms.

Macromolecule

A large biological polymer (carbohydrates, proteins, lipids, nucleic acids) built from monomers.

Carbohydrate

Macromolecule made of C, H, O; monomers are monosaccharides; functions include energy storage and structure.

Protein

Macromolecule composed of amino acids; functions include enzymes, structure, signaling.

Lipid

Nonpolar, hydrophobic macromolecule; includes fats, steroids, phospholipids; diverse roles in storage, membranes, and signaling.

Nucleic acid

Macromolecule (DNA or RNA) that stores and transmits genetic information; monomers are nucleotides.

Monomer

A single subunit that can join with others to form a polymer.

Polymer

A large molecule composed of many repeating monomers linked together.

Monosaccharide

Simple sugar; monomer of carbohydrates (e.g., glucose, fructose).

Disaccharide

Two monosaccharides joined by a glycosidic bond (e.g., sucrose, maltose).

Polysaccharide

Polymers made of many monosaccharides; includes starch and cellulose.

Glycosidic bond

Covalent bond linking carbohydrate monomers.

Starch

Plant storage polysaccharide with primarily alpha-1,4 glycosidic bonds; digestible by humans.

Cellulose

Plant structural polysaccharide with beta-1,4 glycosidic bonds; not digestible by humans.

Sulfur-containing amino acids

Amino acids that include sulfur (e.g., cysteine, methionine) in proteins.

Phosphorus-containing macromolecules

Molecules that include phosphorus, such as phospholipids and nucleic acids.

Nitrogen-containing macromolecules

Molecules that include nitrogen, notably nucleic acids and proteins.

Phosphodiester bond

Covalent bond connecting nucleotides in nucleic acids’ backbone.

Ester bond

Bond between glycerol and fatty acids in lipids.

Glycerol

Three-carbon backbone in triglycerides that bonds to fatty acids via ester bonds.

Amino acid

Amino acids are the monomers of proteins; they contain an amino group, carboxyl group, a central carbon, and an R group.

Peptide bond

Covalent bond formed between amino acids during dehydration synthesis.

N-terminus

End of a protein that contains the amino group.

C-terminus

End of a protein that contains the carboxyl group.

Monomer vs polymer terminology

Monomer is a single unit; polymer is a long chain of many monomers linked together.

Primary structure

Linear sequence of amino acids in a protein.

Secondary structure

Local folding patterns (alpha-helix and beta-pleated sheet) stabilized by hydrogen bonds.

Alpha-helix

Right-handed coiled structure common in proteins’ secondary structure.

Beta-pleated sheet

Sheet-like secondary structure formed by hydrogen bonds between segments of the polypeptide.

Tertiary structure

Three-dimensional shape of a single polypeptide, stabilized by various bonds and interactions.

Disulfide bridge

Covalent bond between cysteine residues that helps stabilize a protein’s structure.

Quaternary structure

Assembly of multiple polypeptides into a functional protein.

N-terminus and C-terminus function

Terminate ends of polypeptide chains with amino and carboxyl groups, respectively, affecting directionality.

DNA

Deoxyribonucleic acid; stores genetic information; typically double-stranded; uses A-T and C-G base pairing.

RNA

Ribonucleic acid; information carrier and functional molecule; typically single-stranded; uses A-U and C-G base pairing.

Nucleotide

Monomer of nucleic acids; consists of a sugar, phosphate, and a nitrogenous base.

Purine

Double-ring nitrogenous bases (A and G) in DNA/RNA.

Pyrimidine

Single-ring nitrogenous bases (C, T, and U) in DNA/RNA.

Adenine

Purine base that pairs with thymine in DNA and with uracil in RNA.

Thymine

Pyrimidine base in DNA that pairs with adenine; replaced by uracil in RNA.

Cytosine

Pyrimidine base that pairs with guanine.

Guanine

Purine base that pairs with cytosine.

Uracil

Pyrimidine base in RNA that pairs with adenine; replaces thymine.

Deoxyribose

Five-carbon sugar in DNA lacking an oxygen atom at the 2' position.

Ribose

Five-carbon sugar in RNA with a hydroxyl group at the 2' position.

5' end

End of a nucleic acid with the phosphate attached to the 5' carbon of the sugar.

3' end

End of a nucleic acid with a free hydroxyl group on the 3' carbon.

Antiparallel

Two strands run in opposite 5' to 3' directions in DNA.

Complementary base pairing

Specific pairing: A with T (or U in RNA), and C with G.

Double helix

The spiral, two-stranded structure of DNA formed by antiparallel strands with base pairing.