Introduction to Genes and Chromosomes (Genetics) & Fundamentals of Nucleic Acids

Comprehensive vocabulary flashcards covering the fundamentals of genetics, nucleic acid chemistry, historic DNA experiments, and various types of functional RNA.

Genetics

The study of heredity and the variation of inherited characteristics, or the genetic properties and features of an organism.

Gene Therapy

An experimental technique that uses genes to treat or prevent disease, allowing doctors to treat a disorder by inserting a gene into a patient's cells instead of using drugs or surgery.

Pharmacogenetics

The application of genetic analysis to predict drug response, efficacy, and toxicity.

A rare congenital genetic condition where the body cannot break down phenylalanine, leading to dangerous accumulation in the blood and brain that can cause brain damage, learning disabilities, behavioral difficulties, and epilepsy if untreated.

Neurofibromatosis 1 (NF1)

A genetic condition affecting approximately 1 in 3,000 births that causes usually non-cancerous (benign) tumours to grow along nerves.

Epidermolysis Bullosa (EB)

A group of rare inherited skin disorders causing skin fragility, where any friction or trauma causes painful blisters.

Nuclein

The acidic substance originally isolated by Friedrich Miescher in 1869 from the nuclei of white blood cells (pus cells) obtained from discarded surgical bandages, later termed nucleic acid.

Nucleotide

A monomer unit of nucleic acids identified by Phoebus Levene, composed of a pentose sugar, a phosphate group, and a nitrogenous base.

Purines

Double-ring nitrogenous bases found in nucleic acids, specifically adenine (A) and guanine (G).

Pyrimidines

Single-ring nitrogenous bases found in nucleic acids, specifically cytosine (C), thymine (T in DNA), and uracil (U in RNA).

Phosphodiester Backbone Orientation

The structural arrangement where the phosphate group connects the $3\text{rd}$ carbon ($3^\prime$) of one pentose sugar to the $5\text{th}$ carbon ($5^\prime$) of the adjacent sugar in line.

Antiparallel Strands

The structural property of DNA where sister strands run in opposite chemical directions ($5^\prime \rightarrow 3^\prime$ and $3^\prime \rightarrow 5^\prime$), held together by complementary hydrogen bonding between purines and pyrimidines.

Major and Minor Grooves

Structural surface features of the DNA double helix where backbones are far apart (major groove) or close together (minor groove), serving as target sites for groove-binding drugs such as distamycin and netropsin.

Bacterial Transformation (Griffith, 1928)

The phenomenon discovered by Frederick Griffith where a chemical component from heat-killed virulent ($S$) pneumococci converted benign ($R$) pneumococci into living virulent cells capable of killing mice.

Transforming Principle (Avery, MacLeod, and McCarty, 1944)

The experimental demonstration that DNA is the substance of heredity, shown by the loss of transforming capability only when treated with deoxyribonuclease, and not with proteinases or ribonuclease.

Messenger RNA (mRNA)

A single-stranded RNA molecule transcribed from DNA in the nucleus that carries the genetic sequence organized in codons to the cytoplasm for protein synthesis.

Transfer RNA (tRNA)

An adaptor RNA molecule with a cloverleaf secondary structure that pairs its anticodon with complementary mRNA codons and carries a corresponding amino acid attached at its $3^\prime$ end.

Ribosomal RNA (rRNA)

A major structural and catalytic RNA constituent of ribosomes that complexes with proteins to carry out translation.

Translation

The biochemical process occurring at ribosomes where mRNA codons are decoded by tRNAs into a growing polypeptide chain.

MicroRNA (miRNA)

Small non-coding RNA molecules ($12\text{--}22\,\text{nt}$ long) that usually bind with incomplete base pairing to target mRNAs to block translation or cause mRNA cleavage.

Small Interfering RNA (siRNA)

Small non-coding RNAs ($12\text{--}22\,\text{nt}$ long) that typically base-pair perfectly with a single specific target mRNA to induce its targeted cleavage.