DNA

• Anitcodon


  A group of three bases on tRNA which are complementary to a codon of the mRNA
• Base


  One of four molecules - adenine, thymine, cytosine, guanine
• Chromosome


  A long DNA molecule that is found in the nucleus in a cell nucleus, which becomes condensed and visible during cell division
• Chromatid


  Is one of two thread-like strands of a replicated chromone. Each sister chromatid contains an exact copy of the double helix DNA, chromatids become visible at the start of mitosis and meiosis
• Codon


  Triplet bases on the mRNA molecule. Different triplets code for different amino acids in a protein
• Diploid


  Describes a cell that contains two sets of chromosomes
• DNA (deoxyribonucleic acid)


  The chemical that forms chromosomes and carries the genetic code
• Double helix


  Describes the shape of the dna molecule, rather like a twisted ladder
• Genetic code


  A table showing which mRNA codons correspond to each amino acid
• Genome


  The entire DNA of an organism
• Haploid


  Describes a cell that contains only one set of chromosomes , such as gametes
• Meiosis


  The form of cell division that o produces four haploid, and genetically different, cells from a diploid parent cell, producing gametes
• Messenger RNA (mRNA)


  A type of RNA that forms a copy of the template strand of DNA during transcription
• Mitosis


  The form of cell division that produces two identical diploid daughter cells from a diploid body cell, used for growth and repair in the body in asexual reproduction
• Mutation


  A rare, random change in DNA. If it occurs within a gene it produces a new allele
• Tumour


  Mass of cells produced by a mutation or uncontrolled cell division
• Ionising radiation


  This is radiation, such as gamma rays, X-rays and ultra-violet radiation that can damage cells and produce mutations in genes
• Mutagen

  A chemical that produces mutations in genes
• Replication ( of DNA )


  The copying of DNA that takes place before cell division
• Ribonucleic acid


  Nucleic acid similar to DNA but made of a single strand, with ribose and sugar and the base uracil instead of thymine, involved in protein synthesis
• Ribosomes


  The site of protein synthesis
• Transcription


  The process by which the information in the base sequence of a strand of the DNA is copied into a molecule of mRNA
• Transfer RNA (tRNA)


  Type of RNA that carries in the base sequence of a stand of the DNA is copied into a molecule of mRNA
• Translation


  The process by which the information un the base sequences of MRNA is used to produce the sequence of amino acids in a protein. Take place at the ribosomes