genes and variation

• what is a genome


  the entire genetic material of an organism
• where is the genetic material stored


  • in the nucleus
  • arranged into chromosomes
• what is a chromosome

  one very long molecule of DNA that's coiled up
• what do genes determine the production of?


  • proteins
  • control the development of different characteristics eg. dimples and how an organism functions
• what do different versions of genes give


  each version gives a different form of a characteristic eg. blue or brown eyes
• what are different versions of the same gene called


  alleles or variants
• variation within a species


  when organisms of the same species are slightly different eg. people having different sized noses, different colour hair, different heights
• genotype


  all the genes and alleles that an organism has
• what is variation caused by


  differences in genotype
• phenotype


  the characteristics that an organism displays
• what does an organisms genotype affect


  its phenotype
• who is an organisms genes inherited from


  its parents
• what else can influence phenotype


  • interactions with the environment eg. a plant grown on windowsill could thrive however one grown in darkness would not.
  • these are called environmental variations
• what are most variation in phenotypes determined by


  a mixture of genetic and environmental factors

  eg. max height a plant can grow to is determined by its genes however if it actually reaches that height depends on its environment (whether it gets enough food)