adenine (A) - A nitrogenous base, one member of the base pair AT (adenine-thymine). 

agarose - Is a product obtained from a seaweed (mostly red algae), that when mixed with water and boiled becomes gel-like and solidifies after cooling.

agarose gel - A gel made of agarose, provides a solid base for loading and running DNA and RNA. 

agriculture - The art and science of raising crops, livestock. It is a broad term and includes numerous specialities like hortculture, agronomy, soil science, breeding, plant pathology, entomology etc.

allele - Alternative form of a genetic locus; a single allele for each locus is inherited from each parent (e.g., at a locus for eye color the allele might result in blue or brown eyes). 

amino acids - the building block of proteins. There are 20 different kinds of amino acids. A protein consists of a specific sequence of amino acids. Amino acids are the building blocks for peptides and proteins.

array -  An orderly arrangement of data. A DNA microarray is an array of DNA samples that can be studied for patterns of gene expression.

ATP -  A molecule which consists of the nitrogenous base adenine linked to the sugar ribose with a chain of three phosphate groups attached to the ribose. ATP is present in all living cells, it is an energy source for many metabolic processes.

autosome - a chromosome not involved in sex determination. The diploid human genome consists of 46 chromosomes, 22 pairs of autosomes, and 1 pair of sex chromosomes (the X and Y chromosomes).

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base - One of the molecules that form DNA and RNA molecules.

base pair (bp) Two nitrogenous bases (adenine and thymine or guanine and cytosine) held together by weak bonds. Two strands of DNA are held together in the shape of a double helix by the bonds between base pairs.

base sequence - The order of nucleotide bases in a DNA molecule; determines structure of proteins encoded by that DNA.

biology - The study of life, includes two broad disciplines botany (study of plants) and zoology (study of animals).

biotechnology - A set of biological techniques developed through basic research and now applied to research and product development. In particular, biotechnology refers to the use by industry of recombinant DNA, cell fusion, and new bioprocessing techniques.

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C value - the amount of haploid DNA that is in the haploid genome of an organism.

C value paradox - either of two paradoxes that are found when comparing the values of different organisms, first, that some organisms appear to have much more DNA than they need to form their genetic code, and second, that some organisms thought th be closely related genetically have C values that differ greatly.

cell - The smallest structural unit of living matter capable of functioning autonomously. The basic unit of any living organism that carries on the biochemical processes of life.

chromosome - A self-replicating structure consisting of DNA complexed with various proteins and involved in the storage and transmission of genetic information; the physical structure that contains genes. One of the threadlike "packages" of genes and other DNA in the nucleus of a cell. Different kinds of organisms have different numbers of chromosomes. Humans have 23 pairs of chromosomes, 46 in all: 44 autosomes and two sex chromosomes. Each parent contributes one chromosome to each pair, so children get half of their chromosomes from their mothers and half from their fathers.

cloning - Using specialized DNA technology to produce multiple, exact copies of a single gene or other segment of DNA to obtain enough material for further study.

codominance - Situation in which two different alleles for a genetic trait are both expressed.

complementary DNA (cDNA) -DNA synthesized from an RNA template by the enzyme reverse transcriptase.

complementary sequence - Nucleic acid base sequence that can form a double-stranded structure with another DNA fragment by following base-pairing rules (A pairs with T and C with G). The complementary sequence to GTAC for example, is CATG. Cytosine (C) A nitrogenous base, one member of the base pair GC (guanine and cytosine) in DNA.

cytoplasm - The content of the cell in between the cell membrane and the nucleus. Cytoplasm holds all the organelles of the cell. Primary constituent of the cytoplasm is water and salts.

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deoxyribose - A type of sugar that is one component of DNA (deoxyribonucleic acid).

diploid - A full set of genetic material consisting of paired chromosomes, one from each parental set. Most animal cells except the gametes have a diploid set of chromosomes. The diploid human genome has 46 chromosomes.

DNA (deoxyribonucleic acid) - The molecule that encodes genetic information. DNA is a double-stranded molecule held together by weak bonds between base pairs of nucleotides. The four nucleotides in DNA contain the bases adenine (A), guanine (G), cytosine (C), and thymine (T). In nature, base pairs form only between A and T and between G and C; thus the base sequence of each single strand can be deduced from that of its partner. DNA repair genes Genes encoding proteins that correct errors in DNA sequencing. DNA replication The use of existing DNA as a template for the synthesis of new DNA strands. In humans and other eukaryotes, replication occurs in the cell nucleus. DNA sequence The relative order of base pairs, whether in a DNA fragment, gene, chromosome, or an entire genome. See also: base sequence analysis.

dominant - An allele that is almost always expressed, even if only one copy is present. See also: gene, genome.

double helix - The twisted-ladder shape that two linear strands of DNA assume when complementary nucleotides on opposing strands bond together.

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electrophoresis - A method of separating large molecules (such as DNA fragments or proteins) from a mixture of similar molecules. An electric current is passed through a medium containing the mixture, and each kind of molecule travels through the medium at a different rate, depending on its electrical charge and size. Agarose and acrylamide gels are the media commonly used for electrophoresis of proteins and nucleic acids. 

enzyme -A protein that acts as a catalyst, speeding the rate at which a biochemical reaction proceeds but not altering the direction or nature of the reaction. 

eukaryote - Cell or organism with membrane-bound, structurally discrete nucleus and other well-developed subcellular compartments. Eukaryotes include all organisms except viruses, bacteria, and bluegreen algae.

exon - The  region of a  gene that codes for protein synthesis.  Where more than one exon exists for a given gene exons are spliced together and represented in the final mRNA.

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forensics - The use of DNA for identification. Some examples of DNA use are to establish paternity in child support cases; establish the presence of a suspect at a crime scene, and identify accident victims.

fraternal twin - Siblings born at the same time as the result of fertilization of two ova by two sperm. They share the same genetic relationship to each other as any other siblings.

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gene - The fundamental physical and functional unit of heredity. A gene is an ordered sequence of nucleotides located in a particular position on a particular chromosome that encodes a specific functional product (i.e., a protein or RNA molecule).

gene mapping - Determination of the relative positions of genes on a DNA molecule (chromosome or plasmid) and of the distance, in linkage units or physical units, between them.

gene pool - All the variations of genes in a species.

gene prediction - Predictions of possible genes made by a computer program based on how well a stretch of DNA sequence matches known gene sequences.

gene product - The biochemical material, either RNA or protein, resulting from expression of a gene. The amount of gene product is used to measure how active a gene is; abnormal amounts can be correlated with disease-causing alleles.

gene therapy - An experimental procedure aimed at replacing, manipulating, or supplementing nonfunctional or misfunctioning genes with healthy genes.

genetic code - The sequence of nucleotides, coded in triplets (codons) along the mRNA, that determines the sequence of amino acids in protein synthesis. A gene's DNA sequence can be used to predict the mRNA sequence, and the genetic code can in turn be used to predict the amino acid sequence.

genetic engineering - Altering the genetic material of cells or organisms to enable them to make new substances or perform new functions.

genetic testing - Analyzing an individual's genetic material to determine predisposition to a particular health condition or to confirm a diagnosis of genetic disease.

genetics - The study of inheritance patterns of specific traits.

genome - All the genetic material in the chromosomes of a particular organism; its size is generally given as its total number of base pairs.

genome project - Research and technology-development effort aimed at mapping and sequencing the genome of human beings and certain model organisms.

genomic library - A collection of clones made from a set of randomly generated overlapping DNA fragments that represent the entire genome of an organism.

Genomics - The study of sequence, structure and function of the genome.

guanine (G) - A nitrogenous base, one member of the base pair GC (guanine and cytosine) in DNA. See also: base pair, nucleotide.

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haploid - A single set of chromosomes (half the full set of genetic material) present in the egg and sperm cells of animals and in the egg and pollen cells of plants. Human beings have 23 chromosomes in their reproductive cells.

human genome initiative - Collective name for several projects begun in 1986 to create an ordered set of human DNA segments from known chromosomal locations, develop new computational methods for analyzing genetic map and DNA sequence data, and develop new techniques and instruments for detecting and analyzing DNA. The joint national effort, is known as the Human Genome Project.

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identical twins - Twins produced by the division of a single zygote; both have identical genotypes.

inherit - In genetics, to receive genetic material from parents through biological processes. 

insertion - A chromosome abnormality in which a piece of DNA is incorporated into a gene and thereby disrupts the gene's normal function. 

intron - A noncoding region of a gene that is transcribed, but later spliced out, and therefore is not represented in the final mRNA.

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jumping genes -  Mobile segments of DNA that randomly insert themselves in the genome of a cell.

junk DNA - Stretches of DNA that do not code for genes; most of the genome consists of so-called junk DNA which may have regulatory and other functions. Also called non-coding DNA.

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kilobase (kb) - Unit of length used for measuring DNA fragments that is equal to 1000 nucleotides.

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ligase - The enzyme that aids in joining two ends of DNA (could be ends of one or more DNA molecules).

ligation - The process of joining two pieces of DNA together. 

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megabase (Mb) - Unit of length for DNA fragments equal to 1 million nucleotides.

meiosis - The process of two consecutive cell divisions in the diploid progenitors of sex cells. Meiosis results in four rather than two daughter cells, each with a haploid set of chromosomes.

mendelian inheritance - One method in which genetic traits are passed from parents to offspring. Named for Gregor Mendel, who first studied and recognized the existence of genes and this method of inheritance.

mRNA (messenger RNA) - RNA that serves as a template for protein synthesis.

mitosis - The process where a cell nucleus divides into two daughter nuclei, each having the same genetic component as the parent cell.

Modified nucleotide base - Nucleotide bases that differ from deoxynucleotides (dNTP). Like ddNTPs which have a hydrogen atom at the 3' carbon replacing the OH group there by does not allow further strand elongation (unable to form phosphodiester bond with the next deoxynucleotide).

molecular biology - The study of the structure, function, and makeup of biologically important molecules.

molecular genetics - The study of macromolecules important in biological inheritance.

mutagen - An agent that causes a permanent genetic change in a cell. Does not include changes occurring during normal genetic recombination.

mutation - Any heritable change in DNA sequence.

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nucleotide - A subunit of DNA or RNA consisting of a nitrogenous base (adenine, guanine, thymine, or cytosine in DNA; adenine, guanine, uracil, or cytosine in RNA), a phosphate molecule, and a sugar molecule (deoxyribose in DNA and ribose in RNA). Thousands of nucleotides are linked to form a DNA or RNA molecule. See also: DNA, base pair, RNA.

nucleus - The central cell structure that houses the chromosomes.

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There are no words under O at this time.

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polymerase, DNA or RNA - Enzyme that catalyzes the synthesis of nucleic acids on preexisting nucleic acid templates, assembling RNA from ribonucleotides or DNA from deoxyribonucleotides.

prokaryote -Cell or organism lacking a membrane-bound, structurally discrete nucleus and other subcellular compartments. Bacteria are examples of prokaryotes.

protein - A large molecule composed of one or more chains of amino acids in a specific order; the order is determined by the base sequence of nucleotides in the gene that codes for the protein. Proteins are required for the structure, function, and regulation of the body's cells, tissues, and organs; and each protein has unique functions. Examples are hormones, enzymes, and antibodies.

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There are no words under Q at this time.

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recessive gene - A gene which will be expressed only if there are 2 identical copies or, for a male, if one copy is present on the X chromosome. 

retrotransposon -  A transposon (mobile DNA segment) that was created by reverse transcription of an RNA molecule.

ribose - The five-carbon sugar that serves as a component of RNA.

ribosomes - Subcellular unit composed of specific rRNA molecules and a large number of proteins that are responsible for protein synthesis.

RNA (Ribonucleic acid) - A chemical found in the nucleus and cytoplasm of cells; it plays an important role in protein synthesis and other chemical activities of the cell. The structure of RNA is similar to that of DNA. There are several classes of RNA molecules, including messenger RNA, transfer RNA, ribosomal RNA, and other small RNAs, each serving a different purpose.

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Sanger method - Dideoxynucleotide sequencing that utilizes ddNTPs.(modified nucleotide bases).

sequencing - Determination of the order of nucleotides (base sequences) in a DNA or RNA molecule or the order of amino acids in a protein.

sex chromosome - The X or Y chromosome in human beings that determines the sex of an individual. Females have two X chromosomes in diploid cells; males have an X and a Y chromosome. The sex chromosomes comprise the 23rd chromosome pair in a karyotype.

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thymine (T) - A nitrogenous base, one member of the base pair AT (adenine-thymine).

transcribe - The process of transcription.

transcription - The synthesis of an RNA copy from a sequence of DNA (a gene); the first step in gene expression.

transfer RNA (tRNA) - A class of RNA having structures with triplet nucleotide sequences that are complementary to the triplet nucleotide coding sequences of mRNA. The role of tRNAs in protein synthesis is to bond with amino acids and transfer them to the ribosomes, where proteins are assembled according to the genetic code carried by mRNA.

transfiguration -  The act of transforming; a change in appearance or character or circumstances.

transformation - A process by which the genetic material carried by an individual cell is altered by incorporation of exogenous DNA into its genome.

transgenic - An experimentally produced organism in which DNA has been artificially introduced and incorporated into the organism's germ line. 

translation - The process in which the genetic code carried by mRNA directs the synthesis of proteins from amino acids.

transposon -  a mobile segment of DNA.

trisomy - Possessing three copies of a particular chromosome instead of the normal two copies.

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There are no words under U at this time.

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There are no words under V at this time.

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There are no words under W at this time.

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X chromosome - One of the two sex chromosomes, X and Y.

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Y chromosome - One of the two sex chromosomes, X and Y.

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Glossary References