This statement is true. The **B allele** of the ABO gene encodes an **α1,3-D-galactosyltransferase** enzyme. This enzyme transfers a **D-galactose** sugar from the donor substrate UDP-galactose to the terminal galactose of the H antigen (which already has a fucose attached). This addition creates the **B blood group antigen**. In contrast, the **A allele** encodes an enzyme that transfers **N-acetylgalactosamine**. The **O allele** produces a non-functional enzyme. This specificity of the sugar transferred is the fundamental biochemical difference between A and B antigens.

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Zambia

• loveness Phiri – 1084 pts

• Visual Pathway Lesions
• Positive and Negative Symptoms
• Hallucinations and Delusions
• Antipsychotic Medications
• Emergency: Environmental Emergencies