Blood bank 4.1 Genetics and Immunology of Blood Groups

Question 1

1. What type of serological testing does the blood bank technologist perform when determining the blood group of a patient?
   A. Genotyping
   B. Phenotyping
   C. Both genotyping and phenotyping
   D. Polymerase chain reaction

Answer 1

B. Phenotyping

Question 2

2. If anti-K reacts 3+ with a donor cell with a genotype KK and 2+ with a Kk cell, the antibody is demonstrating:
   A. Dosage
   B. Linkage disequilibrium
   C. Homozygosity
   D. Heterozygosity

Answer 2

A. Dosage

Question 3

3. Carla expresses the blood group antigens Fya, Fyb, and Xga. James shows expressions of none of these antigens. What factor(s) may account for the absence of these antigens in James?
   A. Gender
   B. Race
   C. Gender and race
   D. Medication

Answer 3

C. Gender and race

Question 4

4. Which of the following statements is true?
   A. An individual with the BO genotype is homozygous for B antigen
   B. An individual with the BB genotype is homozygous for B antigen
   C. An individual with the OO genotype is heterozygous for O antigen
   D. An individual with the AB phenotype is homozygous for A and B antigens

Answer 4

B. An individual with the BB genotype is homozygous for B antigen

Question 5

5. Which genotype is heterozygous for C?
   A. DCe/dce
   B. DCE/DCE
   C. Dce/dce
   D. DCE/dCe

Answer 5

A. DCe/dce

Question 6

6. Which genotype(s) will give rise to the Bombay phenotype?
   A. HH only
   B. HH and Hh
   C. Hh and hh
   D. hh only

Answer 6

D. hh only

Question 7

7. Meiosis in cell division is limited to the ova and sperm producing four gametes containing what complement of DNA?
   A. 1N
   B. 2N
   C. 3N
   D. 4N

Answer 7

A. 1N

Meiosis involves two nuclear divisions in succession resulting in four gametocytes, each containing half the number of chromosomes found in somatic cells or 1N.

Question 8

8. A cell that is not actively dividing is said to be in:
   A. Interphase
   B. Prophase
   C. Anaphase
   D. Telophase

Answer 8

A. Interphase

Question 9

9. Which of the following describes the expression of most blood group antigens?
   A. Dominant
   B. Recessive
   C. Codominant
   D. Corecessive

Answer 9

C. Codominant

Question 10

10. What blood type is not possible for an offspring of an AO and BO mating?
    A. AB
    B. A or B
    C. O
    D. All are possible

Answer 10

D. All are possible

Question 11

11. The alleged father of a child in a disputed case of paternity is blood group AB. The mother is group O, and the child is group O. What type of exclusion is this?
    A. Direct/primary/first order
    B. Probability
    C. Random
    D. Indirect/secondary/second order

Answer 11

D. Indirect/secondary/second order

An indirect/secondary/second order, exclusion occurs when a genetic marker is absent in the child but should have been transmitted by the alleged father. In this case, either A or B should be present in the child.

Question 12

12. If the frequency of gene Y is 0.4 and the frequency of gene Z is 0.5, one would expect that they should occur together 0.2 (20%) of the time. In actuality, they are found together 32% of the time. This is an example of:
    A. Crossing over
    B. Linkage disequilibrium
    C. Polymorphism
    D. Chimerism

Answer 12

B. Linkage disequilibrium

Linkage disequilibrium is a phenomenon in which alleles situated in close proximity on a chromosome associate with one another more than would be expected from individual allelic frequencies.

Question 13

13. In the Hardy-Weinberg formula, p2 represents:
    A. The heterozygous population of one allele
    B. The homozygous population of one allele
    C. The recessive allele
    D. The dominant allele

Answer 13

B. The homozygous population of one allele

In the Hardy-Weinberg formula (p2 + 2pq + q2), p2 and q2 represent homozygous expressions, and 2pq represents heterozygous expression. This formula is used in population genetics to determine the frequency of different alleles.

Question 14

14. In this type of inheritance, the father carries the trait on his X chromosome. He has no sons with the trait because he passed his Y chromosome to his sons; however, all his daughters will express the trait.
    A. Autosomal dominant
    B. Autosomal recessive
    C. X-linked dominant
    D. X-linked recessive

Answer 14

C. X-linked dominant

Question 15

15. Why do immunoglobulin M (IgM) antibodies, such as those formed against ABO antigens, have the ability to directly agglutinate RBCs and cause visible agglutination?
    A. IgM antibodies are larger molecules and have the ability to bind more antigen
    B. IgM antibodies tend to clump together more readily to bind more antigen
    C. IgM antibodies are found in greater concentrations than IgG antibodies
    D. IgM antibodies are not limited by subclass specificity

Answer 15

A. IgM antibodies are larger molecules and have the ability to bind more antigen

Question 16

16. Which of the following enhancement mediums decreases the zeta potential, allowing antibody and antigen to come closer together?
    A. Low ionic strength solution (LISS)
    B. Polyethylene glycol
    C. Polybrene
    D. Dithiothreitol-papain (ZZAP)

Answer 16

A. Low ionic strength solution (LISS)

Question 17

17. This type of antibody response is analogous to an anamnestic antibody reaction.
    A. Primary
    B. Secondary
    C. Tertiary
    D. Anaphylactic

Answer 17

B. Secondary

An anamnestic response is a secondary immune response in which memory lymphocytes respond rapidly to foreign antigen in producing specific antibody. The antibodies are IgG and are produced at lower doses of antigen than in the primary response.

Question 18

18. Which antibodies to a component of complement are contained in the rabbit polyspecific anti-human globulin (AHG) reagent for detection of in vivo sensitization?
    A. Anti-IgG and anti-C3a
    B. Anti-IgG and anti-C3d
    C. Anti-IgG and anti-IgM
    D. All of these options

Answer 18

B. Anti-IgG and anti-C3d