Two Parents with Type a and Type B Blood Have

question 38

Multiple Choice

Two parents with Type A and Type B blood have a child with Type AB blood. How is this possible?

• A) Type A blood is codominant with Type B blood, so both alleles are expressed equally.
• B) Type A blood is incompletely dominant to Type B blood. This means that individuals with alleles for both Type A and Type B will express a blended intermediate between these two blood types.
• C) This is not possible. The child cannot be their biological child.
• D) Type A blood is co-recessive with Type B blood, so as long as there is not a dominant blood type present, both recessive alleles will be expressed equally.

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Definitions:

Desmosomes

Cell structures specialized for cell-to-cell adhesion, critical in maintaining the structural integrity of tissues.

Tight Junction

A specialized connection between two adjacent cells forming a barrier that regulates the passage of substances in the intercellular space.

Intercalated Disc

Unique links among heart muscle cells that enable the heart to contract in unison.

Gap Junction

Specialized intercellular connections between a multitude of animal cell-types that directly connect the cytoplasm of two cells, allowing various molecules, ions, and electrical impulses to directly pass through a regulated gate between cells.