Biochemistry: Biological Macromolecules, Carbohydrates, Lipids, Proteins, and Nucleic Acids

A complete set of vocabulary flashcards reviewing key terms, definitions, chemical structures, and properties across Nucleic Acids, Proteins, Lipids, Biological Macromolecules, and Carbohydrates.

Nucleic Acids

Macromolecules that contain the genetic information of an organism and exist as polymers made of long chains of nucleotide monomers.

Nucleotide

The structural monomer unit of nucleic acids, consisting of three distinct parts: a 5-carbon sugar, a phosphate group, and a nitrogenous base.

Deoxyribose

The 5-carbon sugar found in DNA nucleotides, distinguished by having no hydroxyl ($\text{-OH}$) group on its $2'$ carbon.

Ribose

The 5-carbon sugar found in RNA nucleotides, distinguished by having an hydroxyl ($\text{-OH}$) group on its $2'$ carbon.

Purines

Nitrogenous bases containing a two-ring structure, specifically adenine and guanine.

Pyrimidines

Nitrogenous bases containing a single-ring structure, specifically cytosine, thymine (in DNA), and uracil (in RNA).

Phosphodiester Linkage

The covalent bond that joins the sugar group of one nucleotide to the phosphate group of a second nucleotide in a nucleic acid strand.

Complementary Base Pairing

The specific bonding rule between nitrogenous base pairs on opposite strands where adenine pairs with thymine (or uracil in RNA), and guanine pairs with cytosine.

Gene

A specific sequence segment of nitrogenous bases in DNA that carries the genetic information needed to code for a protein.

Amino Acid

The monomer building block of proteins, consisting of a central carbon atom bonded to a hydrogen atom, an amino group ($\text{NH}_2$), a carboxyl group ($\text{COOH}$), and a variable side chain (R group).

Essential Amino Acids

The 9 amino acids out of 20 that cannot be synthesized by human cells and must be consumed in the diet.

Peptide Bond

The covalent bond formed between two amino acids through a condensation synthesis reaction.

Primary Protein Structure

The unique linear sequence of amino acids linked together in a specific order along a polypeptide chain.

Secondary Protein Structure

The local repetitive folding of a polypeptide chain into an $\alpha$-helix or a $\beta$-pleated sheet, stabilized by hydrogen bonds between backbone $\text{C=O}$ and $\text{N-H}$ groups.

Tertiary Protein Structure

The overall 3D shape of a single polypeptide chain resulting from interactions among R groups, including hydrogen bonds, disulfide bridges, electrostatic interactions, and hydrophobic effects.

Quaternary Protein Structure

The functional 3D arrangement resulting from two or more polypeptide chains joining together into a multi-subunit protein complex.

Molecular Chaperones

Specialized proteins that assist other newly synthesized proteins in folding correctly into their functional 3D shapes.

Denaturation

The permanent loss of a protein's biological activity and correct functional shape caused by extreme temperatures or extreme pH.

Lipids

A diverse group of nonpolar organic molecules composed primarily of carbon, hydrogen, and oxygen (with fewer oxygen atoms than carbohydrates) that dissolve in nonpolar substances.

Triglyceride

A fat molecule formed by condensation reactions connecting one glycerol molecule to three fatty acid chains via ester linkages.

Saturated Fat

A lipid containing no double bonds between carbon atoms in its fatty acid chains, making it solid at room temperature due to a high melting point.

Unsaturated Fat

A lipid containing at least one carbon-carbon double or triple bond in its fatty acid chains, remaining liquid at room temperature due to a lower melting point.

Trans Fat

An artificial fat produced during food processing by hydrogenating unsaturated fats, creating unkinked chains that remain solid at room temperature and pose negative health impacts.

Phospholipid

A key membrane lipid composed of one glycerol molecule linked to two nonpolar hydrophobic fatty acid tails and a polar hydrophilic phosphate-R group head.

Phospholipid Bilayer

A two-layer sheet of phospholipids that forms cell membranes, arranged with hydrophilic heads facing aqueous surroundings and hydrophobic tails sheltered inside.

Steroids

A group of nonpolar lipids characterized by a chemical structure of four fused hydrocarbon rings with attached functional groups.

Waxes

Nonpolar lipids composed of long hydrocarbon chains that are solid at room temperature and serve to prevent water loss in plants and animals.

Biological Macromolecules

Large, biologically important organic compounds categorized into four main classes: carbohydrates, lipids, proteins, and nucleic acids.

Polymer

A large chain-like molecule constructed from smaller repeating molecular subunits bound together.

Monomer

The smallest repeating structural unit that serves as a building block for a polymer.

Carbohydrates

Polar, water-soluble organic molecules made of carbon, hydrogen, and oxygen usually in a $1:2:1$ ratio with generic formula $(CH_2O)_n$, functioning in energy storage and cell communication.

Isomers

Molecules that share the exact same chemical formula (such as $C_6H_{12}O_6$) but possess different structural arrangements of their atoms.

Glycosidic Linkage

The covalent bond formed between two monosaccharides through a condensation reaction involving hydroxyl groups.

Glucose

A 6-carbon monosaccharide ($C_6H_{12}O_6$) that acts as the primary energy source for animal cells and is referred to as blood sugar.

Starch

The primary energy storage polysaccharide in plants, consisting of long, linear, mostly unbranched chains of $\alpha$-glucose joined mainly by $\alpha$-1,4-glycosidic linkages.

Cellulose

A tough structural polysaccharide in plant cell walls composed of $\beta$-glucose monomers linked by 1,4-glycosidic linkages with alternating inverted subunits.

Glycogen

A highly branched energy storage polysaccharide in animals composed of $\alpha$-glucose monomers connected by $\alpha$-1,4 and $\alpha$-1,6-glycosidic linkages.