Biol 3140 Exam 4 | Iowa State University

DNA cloning

Production of many identical copies of a DNA sequence.

restriction enzyme

Enzyme that can cleave a DNA molecule at a specific, short sequence of nucleotides. Extensively used in recombinant DNA technology.

recombinant DNA

A DNA molecule that is composed of DNA sequences from different sources.

DNA ligase

Enzyme that seals nicks that arise in the phosphodiester backbone of a DNA molecule; in the laboratory, can be used to join together two DNA fragments.

plasmid

Small, circular DNA molecule that replicates independently of the genome. Used extensively as a vector for DNA cloning.

transformation

Process by which cells take up DNA molecules from their surroundings in a way that allows them to permanently express genes present on that DNA.

DNA library

Collection of cloned DNA molecules, representing either an entire genome (genomic library) or copies of the mRNA produced by a cell (cDNA library).

genomic library

Collection of cloned DNA molecules that represents the entire genome of a cell.

cDNA library

Collection of DNA fragments synthesized using all of the mRNAs present in a particular type of cell as a template.

complementary DNA (cDNA)

DNA molecule synthesized from an mRNA molecule and therefore lacking the introns that are present in genomic DNA.

hybridization

Experimental technique in which two complementary nucleic acid strands come together and form hydrogen bonds to produce a double helix; used to detect specific nucleotide sequences in either DNA or RNA.

polymerase chain reaction (PCR)

Technique for amplifying selected regions of DNA by multiple cycles of DNA synthesis; can produce billions of copies of a given sequence in a matter of hours.

dideoxy (Sanger) sequencing

A standard method of determining the nucleotide sequence of DNA; utilizes DNA polymerase and a set of chain-terminating nucleotides.

RNA-Seq

Sequencing technique used to determine directly the nucleotide sequence of a collection of RNAs.

in situ hybridization

Technique in which a single-stranded RNA or DNA probe is used to locate a complementary nucleotide sequence in a chromosome, cell, or tissue; used to diagnose genetic disorders or to track gene expression.0

reporter gene

Gene encoding a protein whose activity is easy to monitor experimentally; used to study the expression pattern of a target gene or the localization of its protein product.

green fluorescent protein (GFP)

Fluorescent protein, isolated from a jellyfish, that is used experimentally as a marker for monitoring the location and movement of proteins in living cells.

transgenic organism

A plant or animal that has stably incorporated into its genome one or more genes derived from another cell or organism.

gene knockout

A genetically engineered animal in which a specific gene has been inactivated.

CRISPR

System for gene editing based on a bacterial enzyme that uses a guide RNA molecule to search for and modify specific nucleotide sequences in the genome.

gene expression

The process by which a gene makes a product that is useful to the cell or organism by directing the synthesis of a protein or an RNA molecule with a characteristic activity.

differentiation

Process by which a pluripotent cell undergoes a progressive, coordinated change to a more specialized cell type, brought about by large-scale changes in gene expression.

promoter

DNA sequence that initiates gene transcription; includes sequences recognized by RNA polymerase and its accessory proteins.

regulatory DNA sequence

DNA sequence to which a transcription regulator binds to determine when, where, and in what quantities a gene is to be transcribed into RNA.

transcription regulator

Protein that binds specifically to a regulatory DNA sequence to switch a gene either on or off.

transcriptional repressor

A protein that binds to a specific regulatory region of DNA to prevent transcription of an adjacent gene.

transcriptional activator

A protein that binds to a specific regulatory region of DNA to stimulate transcription of an adjacent gene.

combinatorial control

Describes the way in which groups of transcription regulators work together to regulate the expression of a single gene.

induced pluripotent stem (iPS) cell

Somatic cell that has been reprogrammed to resemble and behave like a pluripotent embryonic stem (ES) cell through the artificial introduction of a set of genes encoding particular transcription regulators.

cell memory

The ability of differentiated cells and their descendants to maintain their identity.

positive feedback loop

An important form of regulation in which the end product of a reaction or pathway stimulates continued production or activity; can control a variety of biological processes, including enzyme activity, cell signaling, and gene expression.

DNA methylation

The enzymatic addition of methyl groups to cytosine bases in DNA; this covalent modification generally turns off genes by attracting proteins that block gene expression.

epigenetic inheritance

The transmission of a heritable pattern of gene expression from one cell to its progeny that does not involve altering the nucleotide sequence of the DNA.

post-transcriptional control

Regulation of gene expression that occurs after transcription of the gene has begun; examples include RNA splicing and translational control.

regulatory RNA

RNA molecule that plays a role in controlling gene expression.

microRNA (miRNA)

Small noncoding RNA that controls gene expression by base-pairing with a specific mRNA to regulate its stability and its translation.

RNA interference (RNAi)

Cellular mechanism activated by double-stranded RNA molecules that results in the destruction of RNAs containing a similar nucleotide sequence. It is widely exploited as an experimental tool for preventing the expression of selected genes (gene silencing).

small interfering RNA (siRNA)

Short length of RNA produced from double-stranded RNA during the process of RNA interference. It base-pairs with complementary sequences in other RNAs, leading to the inactivation or destruction of the target RNA.

long noncoding RNA

Class of RNA molecules more than 200 nucleotides in length that does not encode proteins. Often used to regulate gene expression.