Blood Types

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Blood Types

• 3. Write down 3 questions 3 facts you know
  about blood.
• Read pgs. 324 beginning with Multiple Alleles
  Govern Blood Types and finish at the end of 325
• If possible answer any of your 3 questions or add
  to your 3 facts if possible.

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Blood Typing

• All ABO blood types are determined by 2 proteins
  called antigens, the A antigen and the B antigen.
  
• These proteins occur on the surface of red blood
  cells.
• An individuals blood may contain one, both or
  neither of these antigens, forming the 4 blood
  groups A, B, AB and O.

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• Blood Type A have the A antigen on the red blood
  cells.
• Blood group B have the B antigen.
• Blood group AB have both A and B antigens.
• Blood group O have no antigens.

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• The A and B alleles are dominant to the O allele.
  
• The A and B alleles are co-dominant with one
  another.

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Blood Group Genotype
A AA or AO
B BB or BO
AB AB
O OO
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• Antibodies are special immune cells that destroy
  antigens that your body does not recognize.
• This results in agglutination, the clumping of
  red blood cells BAD.
• This is why blood types must match.

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Blood Types Antigens on the RBCs Antibodies in the plasma Can get blood from Can give blood to
A A Anti-B O, A A, AB
B B Anti-A O, B B, AB
AB A and B None A, B, AB, O AB
O None Anti-A Anti-B O O
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Problem 1

• A man has been taken to trial in a paternity suit
  by a woman who claims he is the father of her
  son. The man claims innocence. At the trial the
  expert witness disclosed the blood types of all
  three, as follows
• The Woman Type A
• The Man Type B
• The Child Type O
• Could the man be the father of the child?

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Problem 1

• The woman could have the genotype AA or AO
• The man could have the genotype BB or BO
• If the woman possessed the genotype AO and the
  man had BO, then the cross could look like this
• Yes, the man
• could be the father.
• However, any man
• with type B, A or O
• could be the father, so
• this man cannot be indicted
• on this evidence alone.

B O
AB AO
BO OO
A O
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Problem 2

• Mr. and Mrs. Jones have just come home with their
  first child, but they are disturbed because their
  friends say that the baby looks like neither one
  of them. Have they come home with the wrong baby?
  
• Mrs. Jones A Mr. Jones O Baby Jones AB

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Problem 2

• Mrs. Jones could be AA or AO
• Mr. Jones can only be OO
• Mr. Jones can NOT be the natural father!
• Mrs. Jones could be the mother

O O
O O
AO AO
OO OO
AO AO
AO AO
A O
A A
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Problem 3

• John and Barry are hiking when Barry falls down a
  cliff and severs an artery. At the hospital, John
  offers to donate his blood for a direct
  transfusion for Barry. John has type O blood, and
  Barry has type AB. Strictly based on blood type,
  should the hospital accept or refuse Johns
  offer? Why?

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Problem 3

• Accept.
• John has Type O blood, he is a universal donor
  he can donate to any other type.

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Problem 4

• John and Barry are hiking again, and this time
  John falls and gets hurt. Barry offers to return
  to favor of a blood transfusion at the hospital.
  Should the offer be accepted or rejected? Why?

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Problem 4

• Rejected.
• Barry has Type AB Blood. Although he can receive
  blood from any other type, he can only donate to
  other people with Type AB.
• John has Type O Blood. Although he can donate
  blood to any other type, he can only receive
  blood from other people with Type O.
• Otherwise, his anti-A and anti-B antibodies will
  attack the A and B anitgens in the blood, leading
  to agglutination.

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• Biology2008_HumanGenetics.ppt