AP BIOLOGY

HEREDITY

MULTIPLE ALLELES

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
John is Type A, John’s mother is Type O. John marries Rita who is Type AB. What portion of their kids will be Type O?
A
1/4
B
1/2
C
3/4
D
all of them
E
none of them
Explanation: 

Detailed explanation-1: -In most cases, an O parent and an AB parent will have only A or B kids. I added a table at the end of this answer that has all blood type combinations for two parents plus the possible blood types for their children. Exceptions to these rules are extremely rare.

Detailed explanation-2: -Two parents with A blood type can produce a child with either A or O blood types. Two parents with B blood type can produce a child with either B or O blood type. One parent with A and another with B can produce a child with A, B, AB or O blood types.

Detailed explanation-3: -AB blood type is usually a result of getting the A blood type gene from one parent and the B blood type gene from the other parent.

Detailed explanation-4: -Each biological parent donates one of their two ABO alleles to their child. A mother who is blood type O can only pass an O allele to her son or daughter. A father who is blood type AB could pass either an A or a B allele to his son or daughter.

There is 1 question to complete.