Organic Molecules: Nucleic Acids and Biomolecules

Vocabulary flashcards covering organic macromolecules with focus on nucleic acid structures, nitrogenous bases, phosphodiester bonds, DNA/RNA differences, lipids, carbohydrates, and protein mutations.

Nucleotide

The monomer of nucleic acids, composed of a $5$-carbon pentose sugar, a phosphate group attached to the $5'$ carbon, and a nitrogenous base attached to the $1'$ carbon.

Polynucleotide

A polymer composed of multiple nucleotide monomers joined together in a chain.

Pyrimidines

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

Purines

Nitrogenous bases containing a fused double-ring structure of carbon and nitrogen, including adenine and guanine.

Phosphodiester Linkage

The covalent bond joining adjacent nucleotides between the $\text{-OH}$ group on the $3'$ carbon of one sugar and the phosphate group on the $5'$ carbon of the next sugar.

Antiparallel

The arrangement of the two strands in a DNA double helix, where one strand runs in the $5' \rightarrow 3'$ direction and the complementary strand runs in the $3' \rightarrow 5'$ direction.

Complementary Base Pairing

Hydrogen bonding between specific pairs of nitrogenous bases, where adenine pairs with thymine (or uracil in RNA) via $2$ hydrogen bonds and guanine pairs with cytosine via $3$ hydrogen bonds.

Genome

The complete sequence of an individual organism's DNA.

Deoxyribose

The $5$-carbon sugar found in DNA nucleotides, characterized by having a hydrogen atom ($\text{-H}$) attached to its $2'$ carbon.

Ribose

The $5$-carbon sugar found in RNA nucleotides, characterized by having a hydroxyl group ($\text{-OH}$) attached to its $2'$ carbon.

Amphipathic

Describing a molecule, such as a phospholipid, that possesses both a polar (hydrophilic) head and a nonpolar (hydrophobic) tail.

Sickle-Cell Mutation

A point mutation resulting in a single amino acid substitution where negatively charged, hydrophilic glutamic acid is replaced by nonpolar, hydrophobic valine in hemoglobin.

Carbohydrates

Organic molecules with the general formula $C_n(H_2O)_n$ that serve as energy sources, structural elements, and cell recognition markers.

Triglyceride

A lipid consisting of a glycerol molecule bound to $3$ fatty acid chains.

Steroids

A class of lipids defined by a structure of $4$ fused carbon rings.

Carbon Numbering in Nucleotides

The convention using prime ($'$) numbers to designate sugar carbons: $1'$ attaches to the base, $2'$ determines DNA ($\text{-H}$) vs RNA ($\text{-OH}$), $3'$ binds the next nucleotide, and $5'$ attaches to the phosphate group.

DNA vs. RNA Comparison

DNA is double-stranded with deoxyribose sugar and thymine, whereas RNA is single-stranded with ribose sugar and uracil.