Acid
A substance made up of hydrogen atom(s), among other atoms, having a pH in the range from 0-6. Acids usually taste sour and feel slippery to the touch. Litmus paper will tun red when placed in contact with an acidic solution. You should read the caution label when dealing with a chemical that is an acid.
Agar
A “gummy” mixture of sugars (polysaccharides) extracted from red algae. Agar is used as a semi-solid surface (substrate) for microorganisms in the laboratory to grow on.
Agarose
A purified form of agar which serves as a main ingredient in the formation of gel blocks used in electrophoresis.
Amino Acid
The building blocks of proteins. Arranged by the cell, amino acids are carefully ordered and linked (as a chain) to form a specific protein. Alanine, histidine, lysine, proline, and tryptophan are five of the 20 most common amino acids. All amino acids have in common an amino (NH) group and a carboxyl (COOH) group.
Antibiotic Resistance
A property of a cell that enables it to be unaffected by an antibiotic that had previously damaged or killed the cell.
Atomic Weight
The mass of an atom. It is usually expressed in atomic mass units (amu).
Base
A substance having a pH in the range 7-14. Bases taste bitter and are slippery to the touch. Litmus paper will turn blue when placed in contact with a base solution. You should read the caution label when dealing with a chemical that is a base.
Base Pair (bp)
Two nucleotides on opposite single strands of a DNA molecule whose bases are brought together by hydrogen bonding. In DNA, the nucleotide base A (adenine) bonds with T (thymine) and the nucleotide base G (guanine) bonds with C (cytosine). The interactions of these bonds bring complementary single strands of DNA together to form a DNA molecule, or double helix.
Base-pair Substitution (Base Substitution)
A change of one nucleotide base (A ,T,G, or C) and its complimentary partner on a DNA molecule for another nucleotide base. This change is also called a “point mutation”.
Biotechnology
A general term referring to the use of scientific principles and engineering principles to influence specific processes in living organisms for the purposes of transforming human health or the environment. Selective cattle breeding and deliberate crop crosses between varying species of cotton to improve desirable traits are two examples of ancient human practices in biotechnology. More modern practices in biotechnology include: plant tissue culture, gene splicing and recombinant DNA technologies, where the DNA of two or more cells are combined. The word “biotechnology” was first used in 1919 by Karl Ereky.
Cell
The smallest unit of an organism that is able to function independently. It consists of one or more nuclei or a nucleiod, cytoplasm, and various organelles. Cell comes from the Latin word “cella” meaning “small room”.
Chromosome
One very long DNA molecule twisted and wound many times with the help of a protein called histone. Chromosomes are found in the nucleus of a cell and carry an organism’s genetic information in the form of genes. Chromosomes are best seen during the metaphase cycle of a cell.
Codon
A set of three consecutive nucleotides (A ,G, C, U) in mRNA. Similar to DNA, mRNA is produced from the transcription (copying) of DNA into a secondary cellular language (mRNA) using the nucleotides adenine, guanine, cytosine and uracil. The nucleotide base Uracil (U) is not found in DNA. A codon dictate the specific amino acid to be added onto a polypeptide chain. A fully assembled polypeptide chain is called a “protein”.
Deoxyribonucleic Acid (DNA)
DNA is the genetic material of an organism. It contains all of the information necessary to make a new organism. DNA is made up of small molecules called nucleotides. DNA was first discovered in 1869 by Frederick Miescher. The double helix structure of DNA was discovered with the help of X-ray photography by James Watson, Francis Crick, Rosalind Franklin and Maurice Wilkins in 1953.
Denaturation (DNA)
Separation of the two strands of a DNA molecule by heat or a chemical. Extreme heat or specific chemicals disrupt the hydrogen bonds between the nucleotide bases allowing the DNA molecule to be separated into two single strands.
DNAse
Properly called “ deoxyribonuclease”, DNAse is an enzyme that cuts (degrades) DNA molecules.
DNA Ligase
An enzyme that links or joins together the ends of two single strands of DNA, much like you would connect two ropes end to end. The bond joining the two strands is created between the phosphate group on the end of the first strand and the carbon ring on the end of the second strand. This is different from base pairing which involves hydrogen bonding between the bases (A-T) and (G-C) on opposite single strands of DNA to form a double helix.
DNA Polymerase
An enzyme that rapidly directs the joining of single nucleotides (A, T, G, C) into a chain to form one long single strand of DNA. The single strand is later joined to a complementary single strand to form a DNA molecule-double strand of DNA.
Double Helix
The coiled shape two complementary strands of DNA form. The shape is similar in appearance to that of a spiral staircase or twisted ladder. This structure was first identified in 1953 by scientists Watson, Crick, Franklin and Wilkins.
Electrophoresis (Gel Electrophoresis )
A method whereby an electrical current is used to separate DNA fragments according to their size and charge. The DNA is placed on an agarose gel and a current is established. After some time, the DNA fragments move (migrate) and the smallest fragments can be found near the bottom of the gel and, increasingly, the largest fragments near the top. Electrophoresis can be used to study the properties of DNA or protein.
Gene
A sequence of nucleotides (segment of DNA) in a fixed position of a chromosome involved in the production of one or more polypeptide chains. Polypeptide chains form proteins. Genes are the discrete units of hereditary information which are passed from parent to offspring.
Gene Splicing
The joining of one or more genes to another with the help of an enzyme.
Genetic Map
A figure displaying the nucleotide sequence and position of various genes (and/or other genetic markers) along a chromosome (DNA molecule).
Genome
A genome is the inherited material of a cell. Simply put, it is a complete set of chromosomes and thus a complete set of genes . A genome contains all the necessary information to make cellular structures and direct the activities of these structures for the lifetime of an organism.
Genotype
The specific hereditary (total genetic) information that an organism receives from its parents.
Helicase
An enzyme that unwinds DNA molecules-separating the two DNA strands of the double helix during DNA replication.
Hydrophilic
A substancehaving an attraction for water. The substance is soluble in water. Vinegar is an example of an hydrophilic substance.
Hydrophobic
A substance repelling water. The substance is not soluble in water, but forms droplets in water. Oil is an example of a hydrophobic substance.
In vitro
Experiments on biological processes carried out in a test tube .“In vitro” is Latin for “within glass”.
In vivo
Experiments on biological processes in which the experimental substance is placed into a living organism. “In vivo” is Latin for “within the living organism”.
Inhibitor
A chemical substance or object that restrains the function of an enzyme on a living system.
Karyotype
An ordered arrangement of an organism’s chromosome pairs based on size and banding pattern.
Knockout
A change affecting or made to a specific gene that causes a cell (organism) to lose a particular function or ability.
Marker (DNA marker)
A DNA fragment in which its size is known. When run on a electrophoresis gel, the DNA marker through comparison can be used to determine the size DNA fragments for which the size is unknown.
Mass Spectrometer
A machine used to measure the molecular weight (mass) of nucleic acids or proteins.
Melting
A change in state of a substance from a solid to a liquid.
Messenger RNA (mRNA)
A single stranded type of RNA made from DNA during transcription in the cell. mRNA is important because it specifies the amino acid that should be added to a growing polypeptide chain. Polypeptides make the thousands of different types of proteins found in living things.
Microorganism
An organism that requires the aid of a microscope to be seen clearly because it is to small to be seen clearly with the naked eye.
Mitosis
A process in eukaryotic cells in which a cell duplicates itself to form another cell. The original cell and the new cell are called “identical daughter cells” by scientist. The process, mitosis, is divided into five stages: prophase, prometaphase, metaphase, anaphase, and telophase.
Molecular Weight
The sum of the atomic weights of the atoms in a molecule.
Mutagen
A chemical substance able to cause a change in the DNA of living organisms.
Mutant
A cell or organism having a change in its DNA sequence (nucleotide sequence) from its normal (wild-type) DNA sequence.
Mutation
A change in DNA sequence (nucleotide sequence) of an organism. A mutation is made whenever a nucleotide base (A, T, G, C) is deleted (removed), changed, displaced, or added in a DNA sequence. While not all mutations affect an organism, a change in DNA sequence can have big effects on a cell or organism when it leads to a transformation in the type of protein produced or a change in the amount of protein produced.
Nucleotide
A nucleotide is a small molecule made up of 1.) a purine or pyrimidine base referred to as a nucleotide base. This base is linked to 2.) a 5 carbon ring sugar molecule called deoxyribose in DNA (ribose in RNA) which in turn is linked to 3.) a phosphate group.
There are four possible nucleotides in DNA. Nucleotides receive their name from their nucleotide base type: adenine (A); cytosine (C); guanine (G); and thymine (T). Uracil (U) is the nucleotide base found in RNA, it replaces thymine (T). Much like the repeated additions of one bead to a thread would form a beaded necklace, the repeated “linking together” or bonding of nucleotides form a single strand of DNA.
Nucleus
The spherical shaped organelle in the cytoplasm of a eukaryotic cell that contains genetic material (DNA) and controls various functions necessary for the life of the cell.
Organelle
A membrane bound structure found in the cytoplasm of eukaryotic cells which perform specialized functions. A few examples of eukaryotic organelles are chloroplast in green plants, mitochondria in animals and nuclei (plural for nucleus) found in all eukaryotic cells.
Organism
Any living animal, plant, bacteria, fungus, or virus.
Osmosis
The flow of water (diffusion) across a semipermeable membrane into another aqueous solution having a greater amount of solute.
Phenotype
The physical and physiological features (traits) of an organism; the visible characteristics of an organism. An organism phenotype is determined by its genotype. “Phenotype” was coined by Wilhelm Johannsen in 1909.
Physical Map (of genome)
A diagram of the linear order of genes in a genome which also shows the distance in between those genes.
Plasmid
A circular piece of double stranded DNA found in bacterial cells and some eukaryotic cells that is not part of the bacterial chromosome. Plasmids can carry genes that are not found on the bacterial chromosome and can replicate apart from the normal bacterial chromosome. Certain genes often found on plasmids enable bacteria to be resistant to antibiotics. Plasmids are very important to scientist in the field of biotechnology because they are used in recombinant DNA technology as a means of transport of new DNA (genes) to a host cell.
Polypeptide
A chain of amino acids linked together by peptide bonds. Proteins are often called polypeptides because one or more polypeptides (dependent upon the type of protein) make up a protein.
Polymerase
An enzyme that speeds up (catalyzes) the attachment of nucleotides to each other to form a DNA or RNA strand.
Polymerase Chain Reaction (PCR) Technique
A laboratory technique used by scientist which allows a large quantity of DNA to be made from the repeated copying of a small amount of DNA. The amount of DNA increases exponentially with each round of copying. PCR was developed between 1983 and 1985 by Kary B. Mullis.
Protein
Proteins are the products of genes. Proteins are made up of smaller molecules called amino acids. Codons, a RNA message originating from a sequence of DNA, tell the cell which amino acids to link forming a chain called a “polypeptide”. One or more polypeptides make a protein. Hundreds and sometimes thousands of amino acids are needed to make most proteins. In organisms proteins have many different functions such as: storage; structural support (ex. helping cells maintain their shape); substance transport; movement (ex. muscle contraction); defense (ex. protection against diseases caused by bacteria or viruses) and coordination (ex. managing chemical reactions in the organism). There are thousands of different types of proteins. Fur, toe nails, feathers, muscles, and hormones are all examples of places where proteins can be found. Protein is from the Greek word “ proteios” meaning “the first” or “the most important”. “Protein” was coined in 1838 by Jons Berzelius.
Replication (of DNA)
The process inside a cell by which an exact copy of a DNA or RNA molecule is made. Several enzymes are instrumental in this process, two include: helicase which unwinds the double helix (in DNA) and DNA polymerase which adds nucleotides to the growing (new) strand of DNA.
Restriction Endonucleases
A group on enzymes which are able to cut DNA at specific locations along its length. Bacteria natural produce these enzymes and use them to fight off viral infections. Restriction endonucleases inside the bacterial cell chop up viral DNA and thus render the virus ineffective. Restriction endonucleases are important to research scientist in the field of biotechnology because they allow a DNA molecule to be cut at a specific region and a new gene (segment of DNA) to be inserted in the gap that was created.
Restriction Site
A nucleotide sequence that is “recognized” by an endonuclease. An endonuclease cuts a DNA molecule at the nucleotide sequence it recognizes.
Sequencing (of DNA molecules)
A process used by scientist to determine the consecutive order (sequence) of the nucleotide bases (A, T, G, C) of a DNA molecule.
Toxin
A substance that is poisonous to a living organism.
Trait
A physical characteristic of an organism resulting from the expression of one gene or the expression of a group of genes acting together.
Transcription
The process by which one strand of a DNA molecule is used as a template to produce a single strand of mRNA. In this process genetic information is “rewritten” as RNA. In other words this process is the change in the “genetic language” from DNA to RNA “Transcription” follows the process “replication” and comes before the process “translation”.
Translation
The process in which the genetic information carried by a strand of mRNA (messenger RNA) is used to direct the ordered arrangement of amino acids to form a polypeptide (protein). “Translation” follows the process “transcription”.
Vector
An agent (usually a bacterial plasmid or viral chromosome) used by scientist to carry a piece of inserted foreign DNA, such as a new gene, into a cell.
Wild Type
An organism with the normal or traditional phenotype that is found in nature. “Wild type” is a direct contrast to “domesticated strain”, “natural mutant” and “laboratory mutant”.
Zygote
A diploid (2n) cell produced by the fusion of male and female gametes. In the case of humans, a diploid cell produced by the fusion of a male sperm and female egg.