Macromolecules, Lipids, and Protein Structure Vocabulary

Vocabulary practice flashcards covering macromolecules, lipid properties, membrane fluidity, and protein structural levels.

Macromolecule

A large biological molecule made by connecting smaller molecules together.

Polymerization

The process of joining smaller molecules together to make a larger molecule or polymer.

Dehydration synthesis

A chemical reaction that builds larger molecules by removing water ($\text{H} + \text{OH} \rightarrow \text{H}_2\text{O}$) and forming a new covalent bond.

Hydrolysis

A chemical reaction that breaks covalent bonds by adding water, splitting a larger molecule into smaller molecules.

Lipid

A group of biological molecules that are generally hydrophobic, including fats, oils, phospholipids, and steroids like cholesterol.

Hydrophobic

Describing a substance or molecule that does not interact well with water (water-fearing).

Hydrophilic

Describing a substance or molecule that interacts well with water (water-loving).

Triglyceride

A lipid molecule consisting of one glycerol attached to three fatty acid chains, important for energy storage.

Glycerol

The molecule that forms the backbone of a triglyceride.

Fatty acid

A hydrocarbon chain attached to glycerol in lipid molecules.

Saturated fatty acid

A fatty acid with no carbon-carbon double bonds, resulting in a straight chain that packs closely together, making it less fluid and more viscous.

Unsaturated fatty acid

A fatty acid containing one or more carbon-carbon double bonds, which creates a bend or kink that prevents tight packing and increases fluidity.

Phospholipid

An amphipathic lipid with a hydrophilic head and hydrophobic tails that forms the basic structural foundation of cell membranes.

Amphipathic

Describing a molecule that possesses both hydrophilic and hydrophobic regions.

Phospholipid bilayer

A two-layer phospholipid arrangement where hydrophilic heads face outward toward water and hydrophobic tails point inward away from water.

Fluid mosaic model

A structural model of cell membranes describing a dynamic mix of components (phospholipids, proteins, cholesterol) that can move laterally.

Cholesterol

A steroid lipid with four rings that regulates membrane fluidity by acting as a fluidity buffer.

Protein

A biological polymer made of amino acids connected together into one or more polypeptide chains.

Amino acid

A building block of proteins consisting of a central carbon attached to an amino group, carboxyl group, hydrogen, and a variable R-group.

R-group

The variable side chain of an amino acid that differs between amino acids and determines its chemical properties.

Polypeptide

A chain of amino acids connected together by covalent bonds.

Primary structure

The specific linear sequence or order of amino acids in a polypeptide chain.

Secondary structure

Local folding patterns in a protein backbone, such as $\text{α-helices}$ and $\text{β-sheets}$, stabilized by backbone hydrogen bonds.

$$\text{α-helix}$$

A corkscrew-shaped secondary structure of a protein held together by backbone hydrogen bonds.

$$\text{β-sheet}$$

A flat or sheet-like secondary structure of a protein held together by backbone hydrogen bonds.

Tertiary structure

The overall three-dimensional shape of a single polypeptide chain determined by interactions among R-groups.

Quaternary structure

The overall protein structure formed by the interactions between multiple separate polypeptide chains.

Hydrogen bond

A weak attraction important in secondary structure that can also stabilize tertiary protein structure.

Ionic interaction

An attraction between oppositely charged R-groups in a protein.

Hydrophobic interaction

An interaction where nonpolar hydrophobic R-groups cluster together toward the inside of a protein away from water.

Disulfide bridge

A strong covalent bond formed between certain R-groups that helps stabilize tertiary protein structure.