Glossary of Bold Terms
adenine: a nitrogenous base that is a purine; bonds to thymine
amino acid: basic subunit of proteins; there are 20 amino acids; composed of a central carbon atom bonded to a hydrogen, an amino group, a carboxyl group and a side chain
anticodon: a sequence of three bases of a transfer RNA molecule that pairs with the complementary three nucleotide codon of an mRNA molecule during protein synthesis
atoms: the smallest particle of a chemical element
base pair rules: purines and pyrimidines bond with each other; A-T and C-G
B form of DNA: the form of DNA that is most common; right hand turn of double helix; the form of DNA with the structure as that proposed by Watson and Crick
biotechnology: the use of living organisms or their components to do tasks
Central Dogma of Molecular Biology: transcription of DNA to RNA and the translation of RNA into protein; forms the backbone of molecular biology
codon: a three nucleotide sequence of DNA or mRNA that specifies a particular amino acid
complementary: refers to strand of DNA or mRNA that is formed from a template strand; follows base pairing rules
cytosine: a nitrogenous base that is a pyrimidine; bonds with guanine
dehydration synthesis: a type of reaction where two molecules are bonded together by the removal of water
deoxyribose: a five carbon sugar found in DNA; differs from ribose since it is missing one oxygen atom
DNA (deoxyribonucleic acid): the nucleic acid found in the cells of an organism; the hereditary material passed on during reproduction
double helix: refers to the double stranded model of DNA where two parallel strands are bonded, and twist 360o
enzymes: protein catalysts that are necessary for most of the chemical reactions that occur in cells
genes: a sequence of nucleotides in DNA that codes for a particular tRNA, mRNA or protein; distinct unit of hereditary material found on chromosomes
genetic code: the 64 possible combinations that code for amino acids; deciphered by the mid 1960s
guanine: a nitrogenous base that is a purine; bonds with cytosine
helix: spiraled curve or coiled curve
Human Genome Project: a worldwide endeavor to decipher the identity of all human genes; initiated by the Department of Energy and the National Institutes of Health in 1987 to understand the basis of human hereditary
macromolecule: term for a very large molecule made of of chains of repeating units
messenger RNA (mRNA): the type of RNA that carries the code for a protein from DNA to the ribosome where it is translated
nitrogenous bases: part of nucleotide; two families- purines (A,G) and pyrimidines (T, C, and U)
nucleic acid: macromolecules that are composed of nucleotides; DNA and RNA
nucleotide: the base units of nucleic acids; each contains a sugar, a phosphate group and one of four nitrogenous bases
nucleus: in a eukaryotic cell; a large membrane enclosed organelle that contains the cells’s DNA
peptide bond: the bond formed between two amino acids by dehydration synthesis
phosphate group: a part of a nucleotide; a negatively charged polyatomic ion with one phosphorus bonded to four oxygens
polypeptide: a chain of amino acids joined by a peptide bond
promoter: a specific sequence of nucleotides that signals the beginning of transcription
proteins: organic compounds consisting of one or more chains of amino acids; contain nitrogen as well as carbon, hydrogen and oxygen
protein synthesis: is the process by which proteins are produced. Three generalized stages include initiation (mRNA finds ribosome), elongation (amino acids are added to growing polypeptide chain, and termination (water cleaves protein from mRNA and ribosome complex
purine: a five membered ring fused to a pyrimidine like ring; adenine and guanine
pyrimidine: a six membered ring make up of carbon and nitrogen; thymine, cytosine, and uracil
Recombinant DNA technology: A set of techniques for combining genes in the lab and transferring this recombinant DNA to others cells where it may be expressed
ribose: a five carbon sugar found in RNA
ribosome: cell organelles that are the site of protein synthesis
RNA (ribonucleic acid): The nucleic acid that is transcribed from DNA
RNA polymerase: an enzyme that links together the growing chain of nucleotides in an RNA molecule
terminator sequence: sequence of nucleotides that ends the transcript
thymine: a nitrogenous base that is a pyrimidine; bond to adenine
transcript: refers to the mRNA transcript transcribed from DNA
transcription: the copying of a genetic message from a strand of DNA to a molecule of RNA
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transfer RNA (tRNA): the type of RNA that carries a particular amino acid; anticodon that is complementary to mRNA codon
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translation: the process where information coded in DNA is used for the assembly of a particular amino acid sequence
x-ray crystallography: a method where an x-ray beam passes through a crystal of a particular substance which causes the atoms of the crystal to deflect the x-rays in an orderly array. These diffracted x-rays can expose photographic film to produce a pattern of spots.
Z form of DNA: an alternate form of DNA where the molecule is a left-handed double helix that is longer and thinner than B DNA; has a zig zag appearance
