DNA

• Chromosome

  Long DNA molecule with part of the genetic material of an organism
• Structure of DNA

  A polymer made up of two strands wrapped around eachother to form a double helix
• Sex chromosomes

  23rd pair of chromosomes that determine an individuals sex
• Sex chromosome for females

  XX
• Sex chromosomes for males

  XY
• Gene

  A small section of DNA on a chromosome.

  Each gene codes for a particular sequence of amino acids, to make a specific protein
• Genome

  The entire genetic material of an organism
• How can understanding the genome help science

  Allows scientists to search for genes linked to different diseases

  Could help us understand and treat inherited disorders

  Can be used in tracing human migration patterns from the past
• Allele

  Different versions of a particular gene
• How many alleles of each gene does an individual have

  2
• Homozygous

  Both allele are identical
• Heterozygous

  Alleles are different
• Dominant allele

  Allele which is always expressed even if there’s only one copy of it
• Recessive allele

  Allele which is only expressed if it’s homozygous
• Genotype

  The specific genes or alleles that an individual has
• Phenotype

  The characteristics an organism has as a result of their genotype
• How are characteristics determined

  Determined by the combination of multiple genes and the environment
• Monomers that combine to form DNA

  Nucleotides
• 4 bases

  Adenine

  Thymine

  Guanine

  Cytosine
• What is complementary base pairing

  The idea that DNA bases always pair up in a similar way
• How do the bases pair

  Adenine to Thymine

  Guanine to Cytosine
• How many bases are needed to code for an amino acid

  3
• Triplet/Codon

  Set of 3 bases
• 3 uses of proteins

  Enzymes

  Hormones

  Structural proteins