Biotech - Chapter 4

Terms used in chapter 4 for Biotechnology Science for the New Millennium by Ellyn Daughterly

Gene

A section of DNA on a chromosome that contains the genetic code of a protein.

Nitrogenous base

An important components of nucleic acids (DNA and RNA), composed of one or two nitrogen-containing rings; forms the critical hydrogen bonds between opposing strands of a double helix.

Base pair

The two nitrogenous bases that are connected by a hydrogen bond; for example, an adenosine bonded to a thymine or a guanine bonded to a cytosine

Phosphodiester bond

A bond that is responsible for the polymerization of nucleic acids by linking sugars and phosphates of adjacent nucleotides

Hydrogen bond

A type of weak bond that involves the “sandwiching” of a hydrogen atom between two fluorine, nitrogen, or oxygen atoms; especially important in the structure of nucleic acids and proteins.

Pyrimidine

A nitrogenous base composed of a single carbon ring; a component of DNA nucleotides.

Purine

A nitrogenous base composed of a double carbon ring; a component of DNA nucleotides.

Antiparallel

A reference to the observation that strands on DNA double helix have their nucleotide oriented in the opposite direction to one another.

Semiconservative replication

A form of replication in which each original strand of DNA acts as a template, or model, for building a new side; in this model one of each new copy goes into a newly forming daughter cell during cell division.

Medium

A suspension or gel that provides the nutrients (salts, sugars, growth factors, etc.) and the environment needed for cells to survive; plural is media.

Lysis

The breakdown or rupture of cells.

R plasmids

A type of plasmid that contains a gene for antibiotic resistance.

Transformed

The cells that have taken up foreign DNA and started expressing the genes on the newly acquired DNA.

Vector

A piece of DNA that carries one or more genes into a cell; usually circular as in plasmid vectors.

Operon

A section of prokaryotic DNA consisting of one or more genes and their controlling elements.

RNA polymerase

An enzyme that catalyzes the synthesis of complementary RNA strands from a given DNA strand.

Promoter

The region at the beginning of where RNA polymerase binds; the promoter “promotes” the recruitments of RNA polymerase and other factors required for transcription.

Operator

A region on an operon that can either turn on or off expression of a set of genes depending on the binding of a regulatory molecule.

Beta-galactosidase

An enzyme that catalyzes the conversion of lactose into monosaccharides.

Broth

A liquid media used for growing cells

Agar

A solid media used for growing bacteria, fungi, plant, or other cells

Media preparation

The process of combining and sterilizing ingredients (salts, sugars, growth factors, pH indicators, etc) of a particular medium.

Autoclave

An instrument that creates high temperature and high pressure to sterilize equipment and media.

Enhancer

A section of DNA that increases the expression of a gene.

Silencer

A section of DNA that decreases the expression of a gene.

Transcription Factors

Molecules that regulate gene expression by binding onto enhancer of silencer regions of DNA and causing an increase or decrease in transcription of RNA.

Intron

The region on a gene that is transcribed into an mRNA molecule but not expressed in a protein.

Exon

The region of a gene that directly codes for a protein; it is the region of the gene that is expressed.

Histones

The nuclear proteins that bind to chromosomal DNA and condense it into highly packed coils.

Nonpathogenic

Not known to cause disease

Bacteriophages

The viruses that infect bacteria

Gene therapy

The process of treating a disease or disorder by replacing a dysfunctional gene with a functional one.

Site-specific mutagenesis

A technique that involves changing the genetic code of an organism (mutagenesis) in certain sections (site-specific) of the genome.

Gel electrophoresis

A process that uses electricity to separate charged molecules, such as DNA fragments, RNA, and proteins, on a gel slab.

Agarose

A carbohydrate from seaweed that is widely used as a medium for horizontal gel electrophoresis.

Polyacrylamide

A polymer used as a gel material in vertical electrophoresis; used to separate smaller molecules, like proteins and very small pieces of DNA or RNA.

Ethidium bromide

A DNA stain (indicator); glows orange when it is mixed with DNA and exposed to UV light; abbreviated EtBr.

Methylene blue

A staining dye/indicator that interacts with nucleic acid molecules and proteins, turning them to a very dark blue color.

High through-put screening

The process of examining hundreds or thousands of samples for a particular activity.