TS1 Flashcards

1
Q

What are the various human blood groups?

A

A
B
O
AB

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2
Q

What antigens do the various blood groups possess?

A

A - A
B - B
AB - A and B
O - Neither

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3
Q

What antibodies do the various blood groups produce?

A

A - anti-B
B - anti-A
AB - none
O - anti-A and anti-B

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4
Q

What is Landsteiner’s Law?

A

Anybody without a particular antigen automatically makes antibodies for the antigens they don’t possess.

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5
Q

Why are blood group antibodies different from other antibodies?

A

They are produced automatically, and do not require prior exposure to blood group antigens.

Normally the immune system meets an antigen and then in subsequent exposures, antibodies are made. The theory is that there are bacteria similar to A & B in our bodies and our bodies make antibodies to these very early in life.

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6
Q

What are blood group antigens?

A

Inherited determinants on red blood cells capable of stimulating an antibody response in someone lacking the antigen

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7
Q

What are blood groups?

A

Antigens encoded by the same gene or cluster of genes (inherited together) are assigned to a blood group

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8
Q

In what ways do blood group antigens differ?

A

Blood group antigens differ in their frequency, antigenicity and clinical significance

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9
Q

What are A and B antigens?

A

A and B antigens are carbohydrate groups built onto membrane proteins or lipids by glycosyl-transferase enzymes

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10
Q

Describe alleles A and B

A

Alleles A and B are antithetical alleles coding for enzymes which transfer CHO groups onto a precursor substance, H.

Antithetical allele’s means they are two forms of the same gene.

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11
Q

What is the purpose of the FUT1 gene?

A

FUT1 gene codes for L-fucosyltransferase which forms the H antigen

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12
Q

What is the purpose of the FUT2 gene?

A

FUT2 gene controls the secretor (Se) status

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13
Q

What does the A allele code for?

A

A allele codes for N-acetylgalactosaminyl transferase which forms the A antigen

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14
Q

What does the B allele code for?

A

B allele codes for D-galactosyl transferase which forms the B antigen

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15
Q

What does the O allele code for?

A

It doesn’t. O allele is a null (amorphic) allele of the ABO

gene which leaves the H antigen unmodified

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16
Q

What type of inheritance do A and B alleles display?

A

A and B alleles are co-dominant (i.e. both are expressed if they are inherited), and dominant over O

17
Q

Who possesses the FUT1 gene?

A

Everyone has the FUT1 gene, that codes for the glycolipids on the cell surface, that A and B antigens adhere to.

18
Q

How are the ABO surface antigens affected by which blood group is inherited?

A

Everybody starts off with a H antigen with a fucose at the end.

If you inherit the A blood group, you have an enzyme that puts a galnac onto this to form the A antigen.

In B this puts a gal on, to form the B antigen

In O, it remains unmodified and stays as FUC on its own.

19
Q

What are the two main subgroups of A?

A

A^1 and A^2

20
Q

What percentage of people have A^1?

A

80%

21
Q

What percentage of people have A^2?

A

20%

22
Q

What is the difference between A^1 and A^2?

A

A1 and A2 genes both code for N-acetylgalactosaminyl transferase enzymes

A2 enzyme is less efficient, converting less H substance to A antigen

23
Q

Why are there fewer genotypes giving rise to A^2 groups?

A

A1 is dominant over A2, so the only genotypes giving

rise to A2 phenotype are A2A2 and A2O

24
Q

What percentage of the population have group O blood types?

A
UK 46
Germany 43 
Africans 49
Lapps 18 
Bengalis 22 
SA Indians 100  (exclusively O)
Aborigines 44
25
Q

What percentage of the population have group A blood type?

A
UK 42 
Germany 42
Africans 26 
Lapps 55 (v. high A2 pop.)
Bengalis 24 
SA Indians 0 (exclusively O)
Aborigines 56
26
Q

What percentage of the population have group B blood type?

A
UK 9 
Germany 11 
Africans 20
Lapps 5 
Bengalis 38 (v. high B pop.)
SA Indians 0 (exclusively O)
Aborigines 0 (no B antigens)
27
Q

What percentage of the population have group AB blood type?

A
UK 3
Germany 4
Africans 5
Lapps 12 
Bengalis 16 
SA Indians 0 (exclusively O)
Aborigines 0 (no B antigens)
28
Q

What is the Rh blood group?

A

A group of 45 antigens encoded by two related genes on Chromosome 1

29
Q

What are the 5 common Rh antigens?

A
D
C
c
E
e
30
Q

What is the most important Rh antigen?

A

D

31
Q

What gene codes for the D antigen?

A

RHD

32
Q

What gene codes for the C, c, E, and e antigens?

A

RHCE