Variation in mutation, meiosis and fertilisation

• What is a mutation ?

  
  

  permanent change in the nucleotide sequence of dna 

  • if mutation occurs in gamete cells, the mutation can be inherited, leading to formation of new alleles
• What is somatic mutation ?

  
  

  occurs in a body cell and is not passed onto an offspring (often bad for individual good for collective ) 
• What is gametic mutation>?

  
  

  occurs in sex cell and is heritable
• what is FrameShift Deletion ?

  
  

  A deletion of a nucleotide that shifts the sequence, leading to large scale changes in amino acid sequence/length of polypeptide, resulting in a non-functional protein.
• What is Silent Mutation ?

  
  

  A form of point mutation that results in a codon that codes for the same amino acid.
• What Substitution Missense Mutation ?

  
  

  is A change in one base pair that results in the substitution of one amino acid for another in the resulting polypeptide.
• What is crossing over ?

  
  

  is the exchange of alleles between homologous chromosomes resulting in a mixture of parental characteristics in an offspring. chromosomes contain the same genes can have different alleles at the same point/loci of chromosomes. Chromosmes cross over and exchange different alleles
• What is independent assortment ?

  
  

  the process of random segregation and assortment of chromosomes during anaphase 1 of meiosis resulting in the production of genetically unique gametes
• What is random segregation?

  
  

  the process of random segregation and assortment of chromosomes during anaphase 2 of meiosis resulting in the production of genetically unique gametes
• How does genetic variation occur in fertilisation?

  
  

  in one human male ejaculate there is approximately 300 million sperm, all being genetically unique through the processes above. only one sperm fertilizes an egg, the successful sperm is determined by chance