DNA, Inheritance, and Genetic Technologies

These flashcards cover the vocabulary and key concepts of DNA structure, protein synthesis, genetic inheritance, and modern genetic technologies based on the provided lecture notes.

DNA (Deoxyribonucleic Acid)

A complex macromolecule that holds the master chemical code an organism requires to build proteins and manage life functions.

Gene

A unique, specific segment of a DNA molecule that carries the explicit instruction or sequence for creating one particular heritable characteristic or protein.

Chromosome

A thread-like, long structure found in the cell nucleus composed of tightly coiled strands of DNA packaged with proteins, with humans having $23$ matching pairs ($46$ total) in somatic cells.

Genome

The absolute complete, entire package of hereditary genetic material present within an organism.

Nucleotides

The basic monomer unit of DNA, each composed of a phosphate group, a deoxyribose sugar, and a nitrogenous base.

Sugar-Phosphate Backbone

The alternating chemical structure of sugars and phosphates that forms the outside support rails of the double helix ladder.

Complementary Base-Pairing Rules

The principle where the internal rungs of the DNA ladder link via weak hydrogen bonds such that Adenine ($A$) pairs exclusively with Thymine ($T$) and Guanine ($G$) pairs exclusively with Cytosine ($C$).

Antiparallel Layout

The arrangement in a DNA molecule where two strands run parallel to each other but point in completely opposite directions.

Transcription

The process occurring in the nucleus where enzyme machinery unzips a DNA gene sequence to construct a single-stranded messenger RNA (mRNA) copy.

Translation

The process at the ribosome where the mRNA strand is scanned, and tRNA units transport specific amino acids to be fastened into a growing polypeptide chain.

Codon

A triplet of three bases on an mRNA strand that is scanned by the ribosome to identify the resulting amino acid for a polypeptide chain.

Mitosis

A non-sexual form of cellular division resulting in two genetically identical daughter cells, targeted at physical growth and tissue repair.

Rosalind Franklin

An expert structural chemist who took "Photo $51$" via X-ray diffraction, proving that DNA maintains a uniform, helical spacing template.

Maurice Wilkins

A scientist who worked alongside Franklin and showed her X-ray imagery data to external competitors without her permission or credit.

James Watson & Francis Crick

Scientists who used Franklin's raw data and measurements to build the first accurate physical $3D$ structural model of the antiparallel double helix.

Meiosis

The process of creating gametes (sex cells) that drives genetic diversity through the crossing over and random arrangement of homologous chromosome pairs.

Polygenic Trait

A trait whose visible expression is governed by the additive combination of multiple distinct genes acting simultaneously, such as human height or skin color.

Mutation

A permanent change in a cell's underlying DNA nucleotide sequence which can create new alleles if it occurs in a germline cell.

Dominant Allele

An allele that completely overrides and hides a weaker partner when present in a heterozygous individual.

Recessive Allele

An allele whose trait is only expressed physically if the organism possesses two matching copies.

Allele

An alternative, different form or version of a single gene.

Genotype

The specific combination of alleles an organism possesses in its genetic code, typically represented by letters like $BB$, $Bb$, or $bb$.

Phenotype

The physical, visible appearance or measurable function of a specific trait.

Homozygous

Possessing two identical copies of an allele for a gene, such as $BB$ or $bb$.

Heterozygous

Possessing two different alleles for a gene, such as $Bb$.

HeLa Cell Line

The first immortalized human cell culture, sourced from Henrietta Lacks in $1951$, used globally for medical and cellular research.

Transgenics

The laboratory insertion of a functional gene segment from one species directly into the genome of a completely unrelated species to express a new trait.

Cloning

The use of somatic cell nuclear transfer and matching lab practices to engineer an exact, identical genetic replicate of an existing cell or organism.

CRISPR

A highly efficient gene-editing system that act as "molecular scissors" to precisely locate, cut, and remove or replace target nucleotide sequences.

CAR-T Cell Therapy

An advanced immunotherapy where a patient's T-cells are harvested and genetically modified to recognize and destroy cancer cells.