KEYWORDS

• POLYPEPTIDE: chains of amino acids. Proteins are made up of one or more polypeptide molecules. The amino acids are covalently linked by peptide bonds.
• GENES: a section of DNA that contains the coded information for making polypeptides and functional RNA.
• EXON: coding sequences in DNA that code for amino acids.
• INTRON: non-coding sequences in DNA (junk DNA)
• HOMOLOGOUS CHROMOSOMES: pairs of matching chromosomes
• DIPLOID: full set of chromosomes in a cell (46 in human)
• HAPLOID: half a set of chromosomes in a cell (23 in humans) - gametes are haploid cells.
• MEIOSIS: a type of cell division that produces gametes.
• LOCUS/LOCI: position of a gene on a chromosome
• ALLELE: alternative version of a gene
• ALLELE: alternative form of a gene
• GENOME: the whole of an organisms hereditary information encoded in its DNA.
• PROTEOME: a full range of proteins produced by a genome.
• TRANSCRIPTION: the process of copying a segment of DNA into RNA called mRNA.
• TRANSLATION: the process by which the genetic information stored in the mRNA is translated (decoded) into a sequence of amino acids to form a protein
• TERMINATION: the ending of transcription and it happens once the RNA polymerase encounters sequence on the DNA known as the terminator sequence (stop codon)
• SPLICING: the joining together of the functional exons once the introns are removed.
• INSERTION MUTATIONS: a base gets added into the sequence
• DELETION MUTATIONS: when one or more bases in the DNA are deleted.
• GENE MUTATIONS: involve a change in the DNA base sequence
• SUBSTITUTION MUTATIONS: a single base pair gets replaced with a different base
• SILENT MUTATIONS: the mutation doesnt alter the amino acid sequence of the polypeptide
• MISSENSE MUTATIONS: mutation alters a single amino acid in the polypeptide chain
• NONSENSE MUTATION: introduces a stop codon so formation of polypeptide chain is incomplete
• DEGENERATE: most amino acids are coded for by more than one triplet
• NON-OVERLAPPING: means each base is only read once
• UNIVERSAL: means each triplet codes for the same amino acid in all organisms on earth
• RIBOSOME: the site of biological protein synthesis (translation)
• CHROMOSOME MUTATIONS: results in changes in the number of chromosomes in a cell or changes in the structure of a chromosome.
• NON-DISJUNCTION: occurs when chromosomes fail to separate correctly in meiosis.
• MEIOSIS: a form of nuclear cell division which produces 4 daughter cells each with half the number of chromosomes as the parent cell.
• BIVALENT: a pair of homologous chromosomes, which consists of 2 chromosomes.
• SYNAPSIS: the tight pairing of the homologous chromosomes. it allows matching up of the homologous pairs.
• CHIASMATA: the point where crossing over occurs.
• CROSSING OVER: the genetic recombination by crossing over chromatids
• CODON: a sequence of three adjacent nucleotides in mRNA that codes for one amino acid.
• COMPLEMENTARY DNA: DNA that is made from mRNA in a process that is the reverse of normal transcription.
• GENOTYPE: the genetic composition of an organism
• MUTAGEN: any agent that induces a mutation
• MUTATION: a sudden change in the amount or the arrangement of the genetic material in a cell