24 Questions
Which of the following blood groups can donate blood to someone with type AB blood?
All of the above
What type of antibodies does someone with blood type A have in their plasma?
Anti-B
Which genotype is associated with the production of antigens that do not agglutinate N group?
MM
If an individual has no antigens on the surface of their red blood cells, what is their likely blood type?
O
Which blood group would produce antibodies that agglutinate MN red blood cells?
Both M and N
In the Rhesus system, what is the primary component found on the surface of erythrocytes?
Rhesus factor
Which of the following accurately describes a person with blood type B?
Has anti-A antibodies and B antigens
Which individual can receive blood from any blood group?
AB
What does the term 'multiple alleles' describe?
More than two sets of genes at one locus
Which of the following is NOT a characteristic of multiple alleles?
Multiple alleles always occupy different loci in the chromosome
What is the outcome when any two mutant multiple alleles are crossed?
The phenotype is the mutant type
Who discovered the existence of blood groups in humans?
Karl Landsteiner
What did Karl Landsteiner conclude about the categories of blood?
Blood groups are polymorphic
In the context of multiple alleles, what does the term 'wild type' refer to?
The normal, non-mutant phenotype that is typically dominant
What significant discovery did Ford make about human blood groups in 1979?
Human blood groups fall into about 15 systems
What is the specific position on a homologous chromosome where a gene resides called?
Gene locus
What triggers the production of Rh antigen in an individual?
Presence of at least one dominant Rh gene
What condition can result from the high concentration of anti-Rh antibodies in an Rh-negative individual?
Erythroblastosis fetalis
What must be used to avoid sensitizing an Rh-negative woman during blood transfusion?
Rh-compatible blood
How can the development of Rh incompatibility be prevented after delivery?
By giving the mother an injection of Rh antibodies
What is the primary cause of erythroblastosis fetalis?
Incompatibility of Rh-positive fetus and Rh-negative mother
When does sensitization typically occur in an Rh-negative mother married to an Rh-positive man?
At or just before the birth of the first Rh-positive child
Which statement about Rh antigen production is correct?
Rh antigen is produced only if at least one gene is dominant
What is the purpose of injecting anti-D antibodies into a mother after delivery?
To destroy any fetal cells that have entered the maternal circulation
Study Notes
Multiple Alleles
- Multiple alleles describe the situation where more than two sets of genes at one locus exist.
- A single pair of genes occupies a specific position known as a gene locus on a homologous chromosome.
Characters of Multiple Alleles
- Multiple alleles of a series always occupy the same locus in the chromosome.
- No crossing over occurs within the alleles of the same multiple allele series.
- Multiple alleles always influence the same character.
- The wild type allele is nearly always dominant, while the other mutant alleles in the series may show dominance or an intermediate phenotypic effect.
- When any two of the mutant multiple alleles are crossed, the phenotype is the mutant type and not the wild type.
Blood Group Systems
ABO Blood Group System
- The A, B, AB, and O blood groups in humans are determined by a series of alleles.
- Individuals with allele A have antigen A on their red blood cells and B antibodies in their plasma.
- Individuals with allele B have antigen B on their red blood cells and A antibodies in their plasma.
- Individuals with allele AB have both antigens A and B on their red blood cells and no antibodies in their plasma.
- Individuals with allele O have neither antigen A nor B on their red blood cells and both A and B antibodies in their plasma.
Blood Type Characteristics
- Blood type A: antigen A on red blood cells, B antibodies in plasma
- Blood type B: antigen B on red blood cells, A antibodies in plasma
- Blood type AB: both antigens A and B on red blood cells, no antibodies in plasma
- Blood type O: neither antigen A nor B on red blood cells, both A and B antibodies in plasma
M-N Blood Group System
- Individuals with M blood group have M antigen on their red blood cells and produce antibodies against N antigen.
- Individuals with N blood group have N antigen on their red blood cells and produce antibodies against M antigen.
- Individuals with MN blood group have both M and N antigens on their red blood cells.
Rhesus (Rh) Blood Group System
- The Rh blood group system is determined by the presence or absence of the Rh antigen on red blood cells.
- Individuals with the Rh antigen are Rh-positive (Rh+), while those without it are Rh-negative (Rh-).
- Rh-negative individuals can be immunized by injecting with Rh-positive blood, stimulating the production of anti-Rh antibodies.
- Rh incompatibility between an Rh-negative mother and an Rh-positive fetus can lead to erythroblastosis fetalis or hemolytic disease of the newborn.
- To prevent sensitization, Rh-compatible blood must always be used in blood transfusions, and Rh-negative women can be given an injection of Rh antibodies (anti-D) to prevent sensitization.
Learn about multiple alleles, where more than two sets of genes exist at one locus, and how they affect an individual's phenotypic trait. Understand how the number of allelic forms can be high in a population of individuals.
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