BIOL 1010 General Biology — Lecture 2: Molecules (Carbohydrates and Lipids)

Vocabulary flashcards covering carbohydrates and lipids concepts from Lecture 2.

Carbon

Element with four valence electrons; can form four covalent bonds, providing a backbone for organic molecules.

Functional group

A group of atoms attached to a hydrocarbon that confers chemical properties and reactivity.

Hydroxyl group

Polar -OH group; increases solubility in water; found in alcohols and sugars.

Carbonyl group

C=O group found in aldehydes and ketones; key in sugars and energy-containing molecules.

Carboxyl group

-COOH group; acid; can donate H+; common in fatty acids and amino acids.

Amino group

-NH2 group; acts as a base; common in amino acids.

Sulfhydryl group

-SH group; forms disulfide bonds important for protein structure.

Phosphate group

-OPO3^2− group; polar; involved in energy transfer (ATP) and present in nucleotides and phospholipids.

Methyl group

-CH3 group; nonpolar; influences hydrophobicity and gene expression in some contexts.

Monomer

Small molecule that can join with others to form polymers.

Polymer

Large molecule built by linking repeating monomers.

Macromolecule

Large biomolecule such as carbohydrates, lipids, proteins, and nucleic acids.

Carbohydrate

Organic molecule with empirical formula (CH2O)n; mainly C, H, O; energy storage; includes sugars and starch.

Monosaccharide

Simple sugar; the basic unit of carbohydrates (e.g., glucose).

Glucose

C6H12O6; primary energy source; transported in animal blood.

Disaccharide

Carbohydrate formed by linking two monosaccharides via dehydration reaction.

Sucrose

Disaccharide used by plants for transport; formed from glucose and fructose.

Maltose

Disaccharide formed by two glucose molecules via dehydration.

Lactose

Disaccharide formed by galactose and glucose via dehydration.

Polysaccharide

Carbohydrate polymer; energy storage (starch, glycogen) or structural support (cellulose, chitin).

Starch

Plant storage polysaccharide.

Glycogen

Animal storage polysaccharide; highly branched.

Cellulose

Plant structural polysaccharide; polymer of glucose; not digestible by humans.

Chitin

Structural polysaccharide in arthropods and fungi; polymer of N-acetylglucosamine.

Lipid

Hydrophobic biomolecule insoluble in water; mainly nonpolar; includes fats, oils, waxes; high energy density.

Fatty acid

Long hydrocarbon chain ending in a carboxyl group; monomer of lipids; components of triglycerides and phospholipids.

Glycerol

Three-carbon alcohol that forms triglycerides with fatty acids.

Triglyceride

Lipid composed of glycerol with three fatty acids; primary energy storage form in adipose tissue.

Saturated fatty acid

Fatty acid with no double bonds; straight chain; typically solid at room temperature.

Unsaturated fatty acid

Fatty acid with one or more double bonds; kinked chain; typically liquid at room temperature.

Phospholipid

Lipid with two fatty acids, a glycerol backbone, a phosphate group, and a polar head; amphipathic; major membrane component.

Phospholipid bilayer

Two-layer membrane formed by phospholipids; hydrophobic tails inward, hydrophilic heads outward; forms cell membranes.

Micelle

Spherical arrangement of amphipathic molecules in water; hydrophobic tails inward, heads outward.

Hydrophobic

Nonpolar; water-repelling.

Hydrophilic

Polar or charged; water-attracting.

Polar

Molecule with an uneven distribution of charge, resulting in partial positive and negative regions.

Nonpolar

Molecule with even distribution of charge; generally hydrophobic.

Hydrogen bond

Weak attraction between a hydrogen atom bonded to an electronegative atom and another electronegative atom.

Covalent bond

Strong bond formed by sharing electrons between atoms.

Ionic bond

Bond formed by electrostatic attraction between oppositely charged ions.

van der Waals interaction

Weak attractions between molecules due to transient dipoles.

Dehydration reaction

Chemical reaction that forms a covalent bond by removing water when joining monomers.

Empirical formula for carbohydrates

CH2O (n); carbohydrates are built from carbon, hydrogen, and oxygen in this ratio.