Molecular Biology and Gene Expression Flashcards

Vocabulary flashcards covering DNA technology, gene regulation, and molecular biology terms from the lecture notes.

DNA ligase

An enzyme used as a molecular "paste" to join DNA fragments together to create a continuous strand of recombinant DNA.

PCR (Polymerase Chain Reaction)

An in vitro DNA replication method used to produce specific DNA fragments in a test tube through repeated cycles.

Denaturation

The first step of the PCR cycle occurring at $95^\circ\text{C}$ where DNA strands are separated.

Annealing

The step in PCR where primers stick to the target sequence via hydrogen bonds.

Elongation

The PCR cycle step occurring at $72^\circ\text{C}$ where DNA polymerase synthesizes a new DNA strand.

Genomic library

A collection of restriction fragments representing a species' entire genome cloned into bacteria.

cDNA library

A DNA library populated by fragments created through the reverse transcription of mRNA using reverse transcriptase.

Transcription regulators

Proteins that bind tightly to the major groove of the DNA double helix to control gene expression via hydrogen bonds, ionic bonds, and hydrophobic interactions.

Operon

A cluster of genes with related functions controlled by a single promoter, typically found in bacterial (prokaryotic) genomes.

Nuclease (Restriction enzymes)

Often called "DNA scissors," these enzymes cleave DNA at specific nucleotide sequences; originally a bacterial defense mechanism.

Repressor

A protein that physically restricts RNA polymerase from binding to the promoter, effectively switching a gene off.

Activator

A bacterial protein that assists RNA polymerase in binding to the promoter to switch a gene on; it is not a sigma factor.

Combinatorial control

A mechanism in eukaryotic cells where the expression of a single gene is controlled by the combined action of many different transcription regulators.

Transgenic

An individual organism that contains DNA derived from another species.

Cloning

The production of many identical copies of a specific DNA sequence.

dNTPs

Deoxyribonucleotide triphosphates, which serve as the fundamental building blocks used in DNA synthesis.

Electrophoresis

A method used to separate and view molecules like DNA fragments by size and charge within a gel matrix.

Expression

The process by which information in a gene is used to synthesize a functional protein.

Hybridization

The process of denaturing and renaturing DNA or RNA to create double-stranded molecules for probing purposes.

Phenotype

The outward appearance of an organism, which is fundamentally formed by its proteins.

Plasmid

A small, circular DNA molecule used as a vector during the process of cell transformation.

Primers

Short DNA sequences that "target" a specific DNA sequence for amplification during a PCR cycle.

Recombinant DNA

A DNA molecule that contains genetic information from two different individuals or species.

Reverse Transcriptase

An enzyme that synthesizes a DNA strand using an RNA template.

Sager Method

A widely used DNA sequencing approach also known as Dideoxy sequencing, named after the researcher Sager.

Selective Breeding

A traditional form of genetic manipulation involving the mating of specific organisms to produce desired traits.

TATA Box

A DNA recognition sequence for the first general transcription factor that binds to a eukaryotic promoter.

Transcription

The process where RNA polymerase binds to a promoter to synthesize RNA from a DNA template.

Transformation

The process of causing a cell to take up foreign DNA, thereby changing its phenotype.