Blood groups

• Blood type


  Proteins on the surface of red blood cells
• Blood type phenotypes


  • A
  • B
  • AB
  • O
• Type A blood


  Has A antigens on the surface of red blood cells
• Type B blood


  Has B antigens on the surface of red blood cells
• Type AB blood


  Has both A and B antigens on the surface of red blood cells
• Type O blood


  Doesn't have A or B antigens on the surface of red blood cells
• If you have type B blood


  You can accept another person's type B blood because B is an antigen your body recognizes
• If you try to give a person with type B blood a type A blood


  Their immune system will attack it because A is an antigen they don't recognize
• Type O blood


  Can be donated to everyone
• Type O individuals


  Can only receive blood from another type O
• Type AB blood


  Can receive blood from anyone
• Rh factor


  A protein on the surface of red blood cells
• Blood type is genetically inherited and a great example of multiple alleles
• Determining if a baby belongs to a couple with type A blood

  1. Check baby's blood type

  2. Use Punnett square to determine possible genotypes of parents

  3. Conclude if baby could belong to the couple
• If both parents are heterozygous type A, there is a 25% chance of having a baby with type O blood
• Blood type


  Determined by the kinds of carbohydrate tags on the outside of red blood cells
• Antigens


  The carbohydrate tags on the outside of red blood cells
• Gene


  Encodes an enzyme responsible for building the antigens on the red blood cell membrane
• Alleles of the gene

  • ia allele
  • ib allele
  • little i allele
• ia allele


  Encodes an enzyme that builds type A antigens
• ib allele


  Encodes an enzyme that builds type B antigens
• little i allele


  Does not produce a functional enzyme, does not contribute to antigens
• Blood types


  • Type A
  • Type B
  • Type AB
  • Type O
• Determining blood type


  1. Genotype with 2 alleles

  2. ia allele is dominant to little i

  3. ib allele is dominant to little i

  4. ia and ib are codominant
• Type A blood has red blood cells with only type A antigens
• Type B blood has red blood cells with only type B antigens
• Type AB blood has red blood cells with both type A and type B antigens
• Type O blood has red blood cells without type A or type B antigens
• Blood type


  Determined by the kinds of carbohydrate tags on the outside of red blood cells
• Antigens


  The carbohydrate tags on the outside of red blood cells
• Gene


  Encodes an enzyme responsible for building the antigens on the red blood cell membrane
• Alleles of the gene


  • ia allele
  • ib allele
  • little i allele
• ia allele


  Encodes an enzyme that builds type A antigens
• ib allele


  Encodes an enzyme that builds type B antigens
• little i allele


  Does not produce a functional enzyme, does not contribute to antigens
• Blood types


  • Type A
  • Type B
  • Type AB
  • Type O
• Determining blood type


  1. Genotype with two alleles

  2. ia allele is dominant to little i

  3. ib allele is dominant to little i

  4. ia and ib are codominant
• Type A blood contains red blood cells with only type A antigens
• Type B blood contains red blood cells with only type B antigens
• Type AB blood contains red blood cells with both type A and type B antigens