ABO Blood Group Practice Questions

• ABO blood group system  discovered by Landsteiner
•  Universal donor: O group
• Universal recipient: AB group
• An example of multiple allele

• It consists of three alleles of a single gene I^A, I^B, I^o., here ‘I’ stands for immunoglobulin

• The ABO grouping is based on presence of two inherited blood cell antigens and two serum antibodies.

Blood System

• Individual who posses A group are found to have 'A 'antigen in their blood and 'anti B'  antibodies in the serum. Like wise, B group individuals posses B antigen in their blood and anti 'A 'antibodies in the serum.

•  O type blood group lack A and B antigens but posses anti A and anti B antibodies in the serum. 

• AB blood group  produce both the antigens but no antibodies.

Blood group	Genotypes
A	IAIA, IAio
B	IBIB, IBio
AB	IAIB
O	IOIO

ABO Blood Group Practice Questions & Answers

1.Type of genotype in individual having blood group B will be

a)  I^A I^o

 b) I^B I^o

c)  I^o I^o 

d)  I^A I^B

Ans: I^B I^o

2. A mother of blood group O has a group O child, the father could be of blood type

a) A or B

b) AB only 

c) O only 

d) A or B or O

Ans: d

Mother: O blood group= I^o I^o

Child  : O blood group= I^o I^o

Blood group of father?

Here one allele I^o comes from mother and the other from the father, ie. father can be I^A I^o, I^B I^o, I^o I^o

Ans: A or B or O

3. If the blood groups of mother and father are AB and O, respectively, what are the blood groups possible for their child?

A) AB or A 

B) AB 

C) A or B 

D) AB, A, B or O

Ans: C) A or B  

4. In ABO blood group testing, which one of the following is INCORRECT 

A) A group – agglutination with anti-A antibodies 

B) B group – agglutination with anti-B antibodies 

C) AB group – no agglutination with either anti-A or anti-B antibodies 

D) O group – no agglutination with either anti-A or anti-B antibodies

Ans: C) AB group – no agglutination with either anti-A or anti-B antibodies

5. If the probability of being blood type A is 1/8 and the probability of blood type O

is ½ , what is the probability of being either blood type A or blood type O?

A) 5/8 B) 1/16 C) 1/8 D) 1/2
Ans: A) 5/8

Quiz on Blood Group