Genetics, Molecular Biology, and Biotechnology Review

Flashcards covering key terms and concepts across genetics, molecular biology, classical DNA inheritance experiments, biotechnology tools, and bioinformatics.

Restriction Enzyme

A bacterial enzyme that protects against viral infection by cutting double-stranded DNA at specific recognition sequences.

Plasmid

A circular piece of DNA naturally occurring in bacteria, commonly used as a vector to introduce foreign genes into host bacteria during gene cloning.

Gel Electrophoresis

A biotechnology technique used to separate, visualize, and verify the sizes of DNA molecules.

Polymerase Chain Reaction (PCR)

A molecular biology technique used to rapidly make thousands to millions of copies of a specific DNA region.

DNA Barcoding

A PCR and sequencing application that identifies species or detects mislabeling by analyzing standardized short genomic sequences.

CRISPR-Cas9

A genome-editing system that utilizes a guide RNA to direct the Cas9 nuclease enzyme to cut target genomic DNA adjacent to a PAM sequence.

Bioinformatics

The scientific discipline concerned with biological information flow and the use of computational methods to analyze and store genetic data.

GenBank

An annotated NIH sequence database of all publicly available DNA sequences, updated and shared daily across international partner databases.

Genomics

The subfield of bioinformatics that uses computational tools to analyze total genetic sequence data across whole genomes.

Transcriptomics

The branch of bioinformatics focused on examining mRNA expression, splice isoforms, and RNA structures.

Proteomics

The branch of bioinformatics concerned with assessing amino acid sequences, evaluating protein structures, and predicting protein function.

Central Dogma

The foundational principle describing the directional flow of genetic information from DNA to RNA to protein.

Transcription

The enzymatic process by which RNA polymerase synthesizes a complementary mRNA strand using a DNA template strand.

Translation

The process at the ribosome where the nucleotide sequence of an mRNA transcript is decoded to assemble a chain of amino acids into a polypeptide.

Codon

A three-nucleotide sequence in mRNA that specifies a particular amino acid or translation stop signal.

Anticodon

A triplet of nucleotides on a tRNA molecule that complementary base-pairs with a specific mRNA codon during protein synthesis.

Point Mutation

A genetic change involving the substitution of a single nucleotide base in a gene sequence.

Frameshift Mutation

A genetic mutation caused by the insertion or deletion of nucleotides not divisible by three, shifting the reading frame of the genetic code.

Repressible Operon

An operon, such as the trp operon, that is typically active but can be inhibited when a specific end-product binds to a repressor protein.

Inducible Operon

An operon, such as the lac operon, that is usually turned off but can be activated when a specific inducer molecule inactivates the repressor protein.

Griffith's Transformation Experiment

The 1928 experiment showing that living nonpathogenic R-strain Streptococcus pneumoniae cells were transformed into pathogenic S-strain cells by a heat-killed S-strain extract.

Transforming Principle

The molecular substance responsible for bacterial transformation, demonstrated by Avery, MacLeod, and McCarty in 1944 to be DNA.

Hershey-Chase Experiment

The 1952 study using radioisotopes $^{35}\text{S}$ and $^{32}\text{P}$ in T2 phages, proving that viral DNA, not protein, enters bacterial host cells to direct replication.

Photo 51

The X-ray diffraction image of B-DNA captured by Rosalind Franklin and Raymond Gosling, providing key evidence for the double-helical structure of DNA.

Chargaff's Rules

The observation that in double-stranded DNA, the proportion of adenine equals thymine ($\%A = \%T$) and cytosine equals guanine ($\%C = \%G$).

Semiconservative Model

The model of DNA replication, confirmed by Meselson and Stahl using $^{15}\text{N}$ and $^{14}\text{N}$, where each replicated double helix contains one original parent strand and one newly synthesized strand.

Helicase

An enzyme that unwinds double-stranded DNA at the replication fork during DNA synthesis.

Topoisomerase

An enzyme that breaks, swivels, and rejoins DNA strands to relieve torsional strain ahead of the replication fork.

Primase

An enzyme that synthesizes a short RNA primer to provide a free $3'$ hydroxyl group for DNA polymerase elongation.

DNA Polymerase

An enzyme that synthesizes new DNA by adding complementary nucleotides to the $3'$ end of a growing strand in a $5' \rightarrow 3'$ direction.

DNA Ligase

An enzyme that seals sugar-phosphate backbones by joining Okazaki fragments together on the lagging strand.

Genetics

The scientific study of biological heredity and genetic variation across organisms.

Chromosome

A cellular structure inside eukaryotic nuclei that consists of a long DNA molecule associated with proteins.

Homologous Chromosomes

A pair of chromosomes of similar length, centromere position, and staining pattern that carry genes for the same characters.

Sister Chromatids

Two identical copies of a duplicated chromosome joined along their length by centromeres and cohesion proteins.

Gene

A discrete unit of hereditary information composed of a specific nucleotide sequence in DNA that produces a functional polypeptide or RNA.

Allele

An alternative nucleotide sequence version of a gene that can produce distinguishable phenotypic effects.

Locus

The specific physical position along the length of a chromosome where a particular gene or sequence resides.

Phenotype

The observable physical and physiological traits of an organism, co-constructed by its genotype and environment.

Genotype

The specific genetic makeup or combination of alleles present in an organism.

Homozygous

Having two identical alleles for a specific gene on homologous chromosomes.

Heterozygous

Having two different alleles for a specific gene on homologous chromosomes.

$I^A$ Allele

The ABO blood group allele that encodes glycosyltransferase A, attaching A antigen to the precursor H antigen.

i Allele

The recessive ABO blood group allele caused by a single base deletion that produces a nonfunctional antigen protein.