Doing your lessons in blood | Digital World Biology - Free Printable

Let's solve this step by step.

---

1. Complete the following table

We are dealing with the ABO blood group system, which is controlled by three alleles:
- I^A (codes for A antigen)
- I^B (codes for B antigen)
- i (codes for no antigen, type O)

Each person has two alleles (one from each parent), and the possible genotypes and corresponding blood types are:

| Genotype | Blood Type |
|----------|------------|
| I^AI^A or I^Ai | A |
| I^BI^B or I^Bi | B |
| I^AI^B | AB |
| i i | O |

Now, let’s complete the Punnett square-style table showing all possible combinations of alleles from mother and father.

We label the rows as "Possible alleles from father" and columns as "Possible alleles from mother".

| | A (I^A) | B (I^B) | O (i) |
|----------------------|------------------------|------------------------|-----------|
| A (I^A) | I^AI^A → A | I^AI^B → AB | I^Ai → A |
| B (I^B) | I^BI^A → AB | I^BI^B → B | I^Bi → B |
| O (i) | iI^A → A | iI^B → B | ii → O |

So the completed table looks like:

| | A | B | O |
|----------------------|---------------|---------------|---------------|
| A | A | AB | A |
| B | AB | B | B |
| O | A | B | O |

> Note: The genotype determines the blood type. For example:
> - I^AI^A or I^Ai = Type A
> - I^BI^B or I^Bi = Type B
> - I^AI^B = Type AB
> - ii = Type O

---

2. Use the table to answer the following questions

#### a. Mother: Type A, Father: Type B

- Mother (Type A): Could be either I^AI^A or I^Ai → can pass I^A or i
- Father (Type B): Could be I^BI^B or I^Bi → can pass I^B or i

So possible offspring combinations:

- I^AI^B → AB
- I^Ai → A
- I^Bi → B
- ii → O

✔ Possible blood types: A, B, AB, O

> *Note: This is only if both parents are heterozygous (I^Ai and I^Bi). If one is homozygous, some outcomes may not occur, but since we're asked for all possible, we assume the most variable case.*

#### b. Mother: Type AB, Father: Type B

- Mother (AB): Genotype = I^AI^B → can pass I^A or I^B
- Father (B): Could be I^BI^B or I^Bi → can pass I^B or i

Offspring possibilities:

- I^AI^B → AB
- I^Ai → A
- I^BI^B → B
- I^Bi → B

So possible blood types: A, B, AB

✔ Answer: A, B, AB

> *No O possible because mother cannot pass i, and father might pass i, but even then, the combination would be I^Ai or I^Bi — not ii.*

#### c. Mother: Type O, Father: Type B

- Mother (O): Genotype = ii → can only pass i
- Father (B): Could be I^BI^B or I^Bi → passes I^B or i

Offspring:

- i + I^B → I^Bi → B
- i + i → ii → O

✔ Possible blood types: B, O

#### d. Mother: Type O, Father: Type O

- Both are ii → can only pass i
- Offspring: i + i → ii → O

✔ Only possible blood type: O

---

Extra Credit: Mother had type O blood, one of the grandfathers had type AB blood

Let’s break it down.

- Mother: Type O → genotype = ii
- So she must have inherited i from both parents.
- One of her grandfathers had type AB blood → genotype = I^AI^B
- He could pass either I^A or I^B to his child (mother's parent).
- But the mother is ii, so her father (the grandfather's son) must have passed an i allele to her.
- That means the father of the mother (the son of the AB grandfather) must have been either I^Ai or I^Bi, and he passed the i allele.

But the AB grandfather passed either I^A or I^B to his son (mother's father).
So the mother's father could be:
- I^Ai → if he got I^A from grandfather and i from grandmother
- I^Bi → if he got I^B from grandfather and i from grandmother

Then, that father (I^Ai or I^Bi) passed i to the mother (who is ii).

Now, the mother is ii, so she can only pass i to her children.

The father of the offspring is unknown in this question — we are only told about the mother and her grandfather.

So the offspring will get:
- One allele from mother: i
- One allele from father: unknown, but could be anything depending on father’s blood type

But the question asks: What blood type(s) could be found in the offspring?

Since the mother is ii, she gives i.

The father could be any blood type, but the only constraint is that one of the grandfathers (on the mother's side) was AB — but that doesn't restrict the father of the child.

So the father could have any blood type (A, B, AB, O), so he could pass:
- I^A, I^B, or i

Thus, possible offspring genotypes:
- I^Ai → A
- I^Bi → B
- ii → O

But NOT AB, because mother can’t give I^A or I^B.

✔ Possible blood types: A, B, O

> Why not AB? Because mother is type O (ii), so she can only contribute i, so offspring can never be I^AI^B (AB), unless father contributes both, which is impossible.

Wait — can the father be AB?

Yes! The father could be AB (I^AI^B), so he could pass I^A or I^B.

But still, offspring would be:
- I^Ai → A
- I^Bi → B

So no AB possible.

So regardless of what the father is, the mother is O, so she gives i, and father gives:
- I^A → child is A
- I^B → child is B
- i → child is O

✔ Answer: Possible blood types: A, B, O

> Even though a grandfather had AB, it doesn’t change the fact that the mother is O (ii), so she can only pass i.

---

✔ Final Answers:

#### 1. Completed Table:

| | A | B | O |
|----------------------|---------------|---------------|---------------|
| A | A | AB | A |
| B | AB | B | B |
| O | A | B | O |

---

#### 2. Questions:

a. Mother: A, Father: B → A, B, AB, O

b. Mother: AB, Father: B → A, B, AB

c. Mother: O, Father: B → B, O

d. Mother: O, Father: O → O

---

#### Extra Credit: Mother: O, Grandfather (on mother's side): AB → A, B, O

> The grandfather being AB does not allow the child to be AB, because the mother is O and can only pass i.

---

✔ Final Answer Summary:

1. Table filled as above.
2.
a. A, B, AB, O
b. A, B, AB
c. B, O
d. O
Extra Credit: A, B, O

Let me know if you'd like a visual Punnett square or explanation of inheritance patterns!