Genetic Molecules: DNA, RNA, and Proteins

These flashcards cover the structure and function of genetic molecules including DNA, RNA, and protein structural levels based on the lecture notes.

Friedrich Miescher (1844-1895)

The scientist who identified "Nuclein."

Deoxyribonucleic acid (DNA)

The primary genetic material with the capacity to be replicated, store genetic information, and provide avenues for mutation.

Nucleotides

The sub-units of nucleic acids composed of a nitrogenous base, a pentose sugar, and a phosphate group.

Phosphoester bond

The chemical bond connecting the phosphate group to the pentose sugar in a nucleotide.

Glycosidic bond

The chemical bond connecting the nitrogenous base to the pentose sugar.

Nucleoside

The molecular complex formed by a sugar and a base.

Purines

Double-ringed nitrogenous bases, which include Adenine and Guanine ($PuAG$).

Pyrimidines

Single-ringed nitrogenous bases, which include Cytosine, Thymine, and Uracil ($PyCT$).

Tautomers

Chemical forms with the same molecular formula and same atoms but a different arrangement of bonds.

Tautomeric states (Pyrimidines)

Alternative forms of pyrimidines known as amino and imino.

Tautomeric states (Purines)

Alternative forms of purines known as keto and enol.

Antiparallel

A characteristic of the two strands of DNA where one runs in the $5' \rightarrow 3'$ direction and the other runs in the $3' \rightarrow 5'$ direction.

Rosalind Franklin and Maurice Wilkins

Scientists who performed x-ray crystallography techniques to study DNA.

Chargaff's Rules

Observations stating that purine content equals pyrimidine content, specifically where $A = T$ and $G = C$.

Base stacking

The organization of base pairs inside the helix that contributes to the overall thermodynamic stability of the DNA molecule.

Major and Minor Grooves

Two different types of grooves in the DNA helix formed due to the angle of protrusion.

Chromatin

The complex of DNA and histones found in eukaryotic cells, which organizes into nucleosomes and 30-nm fibers.

Messenger RNA (mRNA)

A type of RNA that carries genetic instructions and is a product of DNA transcription.

Transfer RNA (tRNA)

A type of RNA that brings amino acids to the ribosome.

Ribosomal RNA (rRNA)

A type of RNA that forms part of the ribosome.

Ribozymes

A group of catalytic RNA molecules.

RNase P

A specific ribozyme that catalyzes $tRNA$ synthesis.

Amino acids

The subunits and monomers of proteins, consisting of a carboxyl group ($COOH$), an amino group ($NH_2$), a proton, and a varying R group.

Primary structure

The level of protein structure attained by the formation of peptide bonds.

Secondary structure

The level of protein structure that may take the form of an $\alpha$-helix or a pleated sheet.

Tertiary structure

A level of protein structure consisting of polypeptides with both helices and sheets.

Quaternary structure

The level of protein structure formed whenever multiple folded protein subunits form a complex.

Protein Data Bank (PDB)

An enormous collection of published experiments that enables viewing the 3D structure of proteins.

Protein Resolution

Data on protein structures quantified by the smallest distance identified through x-ray diffraction, usually measured in an Angstrom.