The Biological Molecules

Vocabulary flashcards covering key terms about carbohydrates, lipids, nucleic acids, and proteins from the lecture notes.

Carbohydrates

Organic molecules with a 1:2:1 ratio of carbon, hydrogen, and oxygen (CH2O)n; soluble in water; provide energy and structural roles.

Monosaccharide

The simplest carbohydrate; a single sugar unit (e.g., glucose); building block for larger carbohydrates.

Disaccharide

Two monosaccharides bonded together (e.g., lactose); used for transport and energy.

Oligosaccharide

3–30 monosaccharide units bonded together; mediates cell-to-cell interactions and feeds mutualistic microbes.

Polysaccharide

Large carbohydrate polymers (>30 monosaccharides); energy storage or structural support (e.g., starch, glycogen, cellulose, chitin, hyaluronic acid).

Monomer

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

Polymer

A large molecule made of repeating monomer units.

Glycogen

Storage polysaccharide in animals, mainly in liver and muscle; major energy store.

Starch

Storage polysaccharide in plants; energy reserve.

Cellulose

Structural polysaccharide in plant cell walls; provides rigidity; mutualisms with microbes help digestion in some animals.

Chitin

Structural polysaccharide in arthropod exoskeletons and fungal cell walls; durable and supportive.

Hyaluronic acid

A flexible, lubricating polysaccharide in connective tissue that provides support and reduces friction.

Cellulase

Enzyme produced by microbes that digests cellulose; enables herbivores to access energy from cellulose.

Glucose

A common monosaccharide and key energy source for cells.

Lactose

Disaccharide in mammalian milk composed of glucose and galactose; energy source for infants.

Triglyceride

Primary form of dietary and stored fat; glycerol bound to three fatty acids.

Fatty acid

Hydrocarbon chain with a carboxyl group; building block of lipids and fuel source.

Lipids

Diverse group of hydrophobic molecules (fats, oils, waxes) used for energy storage, membranes, and signaling.

Amino acid

Building blocks of proteins; 20 standard types linked to form polypeptides.

Polypeptide

A chain of amino acids linked by peptide bonds; folds into a protein.

Protein

Macromolecule made of one or more polypeptides; performs structural, enzymatic, and regulatory roles.

Nucleotide

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

Nitrogenous base

Nitrogen-containing component of nucleotides (adenine, thymine/uracil, cytosine, guanine).

5-carbon sugar

Ribose or deoxyribose; sugar component of nucleotides.

Nucleic acid

DNA or RNA; polymers of nucleotides that store and transmit genetic information.

DNA

Deoxyribonucleic acid; stores genetic information in a double-helix.

RNA

Ribonucleic acid; mediates protein synthesis and gene regulation.

Hydroxyl group

OH group; contributes to the water solubility of carbohydrates.

Covalent bond

Electron-pair sharing bond that links atoms; includes carbon–hydrogen bonds that store metabolic energy.

Suffix -ose

Ending used by many carbohydrate names (e.g., glucose, lactose).

Sweet taste receptors

Taste cells that detect sugars and signal sweetness, indicating caloric content and safety.

Glycogen storage site

Stored primarily in liver and muscle cells as a glucose reserve.

Breast milk oligosaccharides

Oligosaccharides in milk that feed mutualistic gut microbes and support infant immunity.

Cell-surface carbohydrates and cancer

Carbohydrate patterns on cell surfaces can aid cancer diagnosis as biomarkers.