Biology Macromolecules and Cell Structure - Vocabulary Flashcards

Vocabulary-style flashcards covering the major concepts from the lecture notes on macromolecules, their subunits, bonds, and protein structure.

Macromolecule

A large molecule formed by linking smaller subunits; major types include carbohydrates, lipids, proteins, and nucleic acids.

Monomer (subunit)

A building block that repeats to form a macromolecule (e.g., monosaccharide, amino acid, nucleotide, or glycerol for lipids).

Carbohydrates

Macromolecules built from simple sugars; functions include energy storage and structural support (cell walls).

Lipids

Hydrophobic molecules with no single repeating subunit; include fats, phospholipids, and steroids; roles in energy storage, membranes, and signaling.

Proteins

Macromolecules made of amino acids joined by covalent bonds; perform structural support, catalysis, signaling, and transport.

Nucleic acids

Macromolecules composed of nucleotides; encode and store genetic information.

Monosaccharide

Single sugar unit (e.g., glucose, galactose, fructose).

Disaccharide

Two sugar units joined by a glycosidic bond (e.g., maltose, sucrose, lactose).

Polysaccharide

Many sugar units; complex carbohydrates such as starch, glycogen, cellulose, and chitin.

Glycosidic bond

Covalent linkage that joins sugar monomers in carbohydrates.

Dehydration/condensation reaction

Synthesis of a macromolecule by joining monomers with loss of water.

Hydrolysis

Breakdown of polymers into monomers with addition of water.

Amino acid

Monomer of proteins; contains amino group, carboxyl group, and a variable R group.

Peptide bond

Covalent bond linking amino acids in a protein.

Polypeptide

A chain of amino acids joined by peptide bonds.

Primary structure

Linear sequence of amino acids in a polypeptide.

Secondary structure

Local folding patterns (alpha-helix and beta-pleated sheet) stabilized by hydrogen bonds.

Tertiary structure

Three-dimensional folded shape of a single polypeptide; determined by R-group interactions and various bonds.

Disulfide bond

Covalent bond between cysteine residues; helps stabilize tertiary structure.

Quaternary structure

Association of two or more polypeptide subunits into a functional complex.

Denaturation

Unfolding of a protein, disrupting its structure and function.

Nucleotides

Monomers of nucleic acids; consist of a sugar, phosphate, and a nitrogenous base.

Nucleic acids

Polymers of nucleotides that store and transmit genetic information (DNA and RNA).

Glycerol

Backbone molecule for triglycerides and phospholipids.

Fatty acid

Hydrocarbon chain that may be saturated (no double bonds) or unsaturated (one or more double bonds).

Triacylglycerol (Triglyceride)

Glycerol bound to three fatty acids; main storage lipid.

Ester linkage

Bond connecting glycerol to fatty acids in triglycerides and phospholipids.

Phospholipid

Lipid with two fatty acids and a phosphate-containing head; forms membranes; amphipathic.

Phospholipid bilayer

Two-layer membrane where hydrophilic heads face water and hydrophobic tails face inward.

Amphipathic

Molecule with both hydrophilic (polar) and hydrophobic (nonpolar) regions.

Steroid

Lipid with four fused carbon rings; nonpolar; includes hormones.

Hydrophobic amino acids

Amino acids with nonpolar R groups; tend to cluster away from water (e.g., valine, leucine, isoleucine, methionine, phenylalanine).

Hydrophilic amino acids

Amino acids with polar or charged R groups; interact with water.

Amino group

NH2 group at the amino terminus of amino acids; basic.

Carboxyl group

COOH group at the carboxyl terminus of amino acids; acidic.

R group

Variable side chain that determines the identity and properties of an amino acid.

Glycine

Small, nonpolar amino acid with a hydrogen R group.

Cysteine

Amino acid with a polar R group that can form disulfide bridges.

Alanine

Hydrophobic amino acid with a small methyl R group.

Valine

Hydrophobic amino acid with a branched R group.

Leucine

Hydrophobic amino acid with a larger branched R group.

Isoleucine

Hydrophobic amino acid with a branched R group; isomer of leucine.

Methionine

Hydrophobic amino acid containing sulfur.

Phenylalanine

Hydrophobic amino acid with an aromatic side chain.

Tryptophan

Hydrophobic amino acid with an indole ring.

Tyrosine

Hydrophobic amino acid with a polar hydroxyl group on an aromatic ring.

Aspartic acid

Hydrophilic acidic amino acid with a negative charge at physiological pH.

Lysine

Hydrophilic basic amino acid with a positive charge at physiological pH.

Arginine

Hydrophilic basic amino acid with a positive charge at physiological pH.

Serine

Hydrophilic polar amino acid with a hydroxyl group.

Threonine

Hydrophilic polar amino acid with a hydroxyl group.

Glutamic acid

Hydrophilic acidic amino acid with a negative charge at physiological pH.

Phospholipid bilayer (revisited)

A lipid bilayer forming the basic structure of cell membranes; amphipathic phospholipids arrange with heads outward and tails inward.

Alpha-helix

A common coil-shaped secondary structure stabilized by intramolecular hydrogen bonds.

Beta-pleated sheet

A secondary structure with strands lying side-by-side, stabilized by hydrogen bonds.

Peptide bond formation

Dehydration reaction that links amino acids to form a peptide bond.

Polypeptide

A polymer consisting of many amino acids linked by peptide bonds.

Primary structure (protein)

The linear sequence of amino acids in a polypeptide.

Secondary structure (protein)

Local folding patterns (alpha-helix, beta-sheet) due to backbone hydrogen bonding.

Tertiary structure (protein)

Overall 3D shape of a single polypeptide, stabilized by various bonds among R groups.

Disulfide bridge

Covalent bond between two cysteine residues that stabilizes protein structure.

Quaternary structure (protein)

Interaction of two or more polypeptide subunits to form a functional protein.

Glycosidic bond

Covalent linkage joining sugar monomers in carbohydrates.

Glycerol backbone

Backbone molecule to which fatty acids attach in lipids like triglycerides and phospholipids.

Saturated fatty acid

Fatty acid with no carbon–carbon double bonds; fully hydrogenated; usually solid at room temperature.

Unsaturated fatty acid

Fatty acid with one or more carbon–carbon double bonds; usually liquid at room temperature.

Saturated fat

Fat containing saturated fatty acids; tends to be solid at room temperature.

Unsaturated fat

Fat containing unsaturated fatty acids; tends to be liquid at room temperature.

Monomer order matters

The sequence of building blocks affects the structure and function of the polymer.

Functional groups

Specific group of atoms that adds characteristic properties and reactivity to a molecule.