Biological Macromolecules and Chemical Reactions

Vocabulary practice flashcards covering biological macromolecules, carbohydrates, lipids, nucleic acids, protein structures, chemical reactions, energy changes, catalysts, and enzymes.

Carbohydrates

Biological macromolecules that serve as the main source of energy for living things (with sugar breakdown producing ATP) and provide structural support in plants and animals.

Starches

Complex carbohydrates stored by plants for energy storage.

Glycogen

The complex carbohydrate form in which animals store glucose.

Cellulose

A carbohydrate used for structural purposes in plants.

Chitin

A carbohydrate used for structural purposes in animals.

Lipids

Biological macromolecules made mostly of carbon and hydrogen that are hydrophobic, insoluble in water, non-polar, and lack true polymers and monomers.

Triglycerides

Fats and oils constructed of glycerol and $3$ fatty acid chains that function in compact energy storage in adipose cells, storing more than $2\times$ as much energy per gram as polysaccharides.

Steroids

Hydrophobic lipids constructed with a carbon skeleton of $4$ fused rings that mediate physiological reactions and serve as components of plasma membranes.

Nucleic Acids

Macromolecules containing hydrogen, oxygen, nitrogen, carbon, and phosphorus that store, transmit, and express hereditary information and determine the primary structure of proteins.

Nucleotides

The monomer units that construct nucleic acids.

DNA and RNA

The two main types of nucleic acids.

Proteins

Biologically functional macromolecules containing CHON that make up $50\text{\%}$ of the dry mass of most cells, constructed from a set of $20$ amino acids.

Polypeptide

Unbranched polymers of amino acids formed by dehydration synthesis reactions.

Amino Acids

Molecules consisting of a central \begin{equation*}\alpha\end{equation*} -carbon bonded to $4$ different partners: a carboxyl group, an amino group, a hydrogen atom, and a side chain (R-group).

R-Group

The variable side chain portion of an amino acid that confers non-polar, polar, negative, or positive properties and determines the chemical nature of a protein.

Peptide Bond

The covalent bond linking amino acids resulting from a dehydration reaction.

Primary Structure

The linear amino acid sequence of a protein.

Secondary Structure

The twisting or folding of amino acids within a polypeptide chain caused by hydrogen bonds in the primary chain backbone, forming \begin{equation*}\alpha\end{equation*} (Alpha) Helices or \begin{equation*}\beta\end{equation*} (Beta) Pleated Sheets.

Tertiary Structure

The overall three-dimensional shape of a polypeptide resulting from interactions between side chains (R groups).

Quaternary Structure

The specific arrangement in space when a protein consists of more than one polypeptide chain.

Denaturation

The unraveling and loss of shape of a protein caused by the destruction of its chemical bonds and interactions due to changes in pH, salt concentration, or temperature.

Hydrolysis Reactions

Chemical reactions involving the breaking of bonds that release energy when they occur.

Dehydration Reactions

Chemical reactions involving the formation of bonds that require the input of energy to occur.

Activation Energy

The energy needed to get a chemical reaction started.

Catalysts

Substances that lower the activation energy required for a reaction, thereby decreasing the amount of time required for the reaction to take place.

Enzymes

Biological catalysts (proteins usually ending in -ase) that speed up cellular chemical reactions by lowering activation energy without being used up, operating at an average rate of about $1\text{k}$ reactions per second.

Substrates

The specific reactants of enzyme-catalyzed reactions.

Active Site

The site on an enzyme where reactants are brought together to react, fitting substrates so precisely it is compared to a lock and key.