Digestive System & Biomolecules

Vocabulary flashcards covering the four biomolecules: Nucleic Acids, Carbohydrates, Lipids, and Proteins.

Macromolecules

Relatively large, complex organic (carbon-based) molecules found in living organisms. Major groups: Nucleic acids, Proteins, Lipids, Carbohydrates.

Monomers

Smaller subunits or building blocks from which macromolecules are built (and can be broken down into).

Metabolism

The sum of all the chemical reactions in the body.

Anabolism

Building molecules (a metabolic process).

Catabolism

Breaking molecules apart (a metabolic process).

Dehydration Synthesis

An anabolic reaction that removes a hydroxyl (-OH) group from one subunit and a hydrogen atom (H) from another subunit to form a covalent bond, releasing a water molecule in the process and requiring energy (endothermic).

Hydrolysis

A catabolic reaction where a molecule of water is added to a covalent bond, breaking the bond and separating the subunits, releasing energy (exothermic).

Carbohydrates

Sugars that store energy (e.g., glucose, fructose, lactose, starch), usually containing carbon, hydrogen, & oxygen in a 1:2:1 ratio; made up of monosaccharides (single sugars).

Monosaccharide

A single sugar made of 3-7 carbons.

Disaccharide

Two monosaccharides chemically joined together by a glycosidic bond.

Polysaccharides

Complex carbohydrates consisting of many-linked simple sugars; used for energy storage (glycogen in animals, starch in plants) and structure (cellulose in plant cell walls, chitin in arthropod exoskeletons).

Lipids

Hydrophobic molecules that are insoluble in water; functions include long-term energy storage, protection, insulation & lubrication, communication & signaling (hormone precursors), and structure (cell membrane phospholipids). Major groups: Triglycerides, Phospholipids, Steroids, Waxes.

Triglyceride

Composed of a glycerol molecule and 3 fatty acid chains.

Saturated Fats

Fats with all single bonds in fatty acid chains, saturated with hydrogen, resulting in straight chains and fats that are solid at room temperature (animal fats).

Unsaturated Fats

Fats with fatty acid chains that have one or more double bonds, allowing room for more hydrogen, resulting in 'kinked' chains and fats that are liquid at room temperature (plant oils).

Trans Fats

Fats formed when hydrogen atoms are added to unsaturated fats (hydrogenation), increasing shelf life of food. Can lead to heart disease by raising LDL (bad cholesterol) and lowering HDL (good cholesterol).

Nucleic Acids

Nucleotide chains that transfer and express genetic information, coding for proteins, directing growth & development, and determining structure & function of cells. Two types: DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).

Nucleotides

Subunits of nucleic acids, consisting of a sugar, a phosphate, and one of four nitrogen bases (Adenine, Guanine, Thymine, Cytosine in DNA; Uracil replaces Thymine in RNA).

Proteins

Polymers made up of amino acid monomers that perform many functions in the body (structural, defensive, enzymes, transport, communication, energy).

Amino Acids

The monomers/subunits of proteins; consists of a central carbon, an amino group (NH2), a carboxyl group (COOH), a side chain (R), and a hydrogen. When broken down, the amino group is converted into ammonia and then into urea to be removed from the body.

Peptide Bond

The bond that forms between amino acids during dehydration synthesis reactions.