A

• Nucleotides


  • Base
  • Phosphate group
  • Sugar
• DNA bases


  • Adenine
  • Thymine
  • Guanine
  • Cytosine
• DNA bases


  Code for different proteins
• Triplet code


  Three bases form a code for an amino acid
• Proteins


  Made up of 12 to 50,000 amino acids
• Start of genes


  ATE (methionine)
• End of genes


  TAA, TAG or TGA
• Protein types


  • Structural
  • Enzymes
  • Regulatory
• Karyotype


  Shows the number and visual appearance of the chromosomes in the cell nuclei of an organism or species
• Human chromosomes


  46, one pair are sex chromosomes, the other 22 are somatic
• Mitosis


  Produces daughter cells, genetically identical, doubles in chromosomes, for growth and repair and produce diploid cells
• Interphase


  Process of cells growing
• Prophase


  Chromatid threads condense and become visible. Centrioles send out spindle fibres which move to opposite poles off the cell and attach to the centromere
• Metaphase


  Chromosomes line up at the equator by their centromere on spindle fibres
• Anaphase


  Sister chromatids separate and are pulled towards opposite poles by spindle fibres
• Telophase


  Nuclear membrane reforms, chromosomes uncoil and are no longer visible, and spindle fibres disassemble
• Cytokinesis


  Cytoplasm divides, cleavage occurs (in animals cell) and two daughter cells form, (plant cells must create cell wall)
• Meiosis


  Gametes are produced, they are genetically different, made from half the chromosomes, produces haploid cells
• Pedigree


  Analyse the pattern of inheritance of a particular trait
• Filled in symbol


  Affected male/female
• Autosomal recessive


  • Trait can skip generations
  • Two affected parents must produce affected offspring
  • An affected child may have an unaffected parent
• Autosomal dominant


  • Trait can't skip generations
  • Two affected parents can have an unaffected child
  • An affected child must have an affected parent