Worksheet on blood type genetics with questions and a diagram of a blood drop.

Problem Analysis:

The task involves understanding blood typing based on genetics and solving inheritance problems using Punnett squares. Blood types are determined by the alleles of the A and B genes, which are codominant to each other but dominant over the recessive O allele. The possible genotypes and phenotypes are as follows:

- Genotypes:
- AA or AO: Type A blood
- BB or BO: Type B blood
- AB: Type AB blood (codominant)
- OO: Type O blood

Solution to Each Part:

#### (a) What are the two genotypes possible for a person who has A blood?
- Type A blood can be produced by two possible genotypes:
- AA (homozygous dominant)
- AO (heterozygous)

Answer:
$$
\boxed{AA \text{ or } AO}
$$

---

#### (b) What genotypes does a person with B blood have?
- Type B blood can be produced by two possible genotypes:
- BB (homozygous dominant)
- BO (heterozygous)

Answer:
$$
\boxed{BB \text{ or } BO}
$$

---

#### (c) What genotype does a person with O blood have?
- Type O blood is produced by only one genotype:
- OO (homozygous recessive)

Answer:
$$
\boxed{OO}
$$

---

#### (d) What are the two possibilities for a person who has AB blood?
- Type AB blood is produced by only one genotype due to codominance:
- AB (heterozygous, with both A and B alleles expressed)

Answer:
$$
\boxed{AB}
$$

---

#### 3. A man with type B blood (genotype BB) is married to a woman with type O blood (genotype OO). Show the cross. What proportion of their children will have?
- Father's genotype: BB (Type B)
- Mother's genotype: OO (Type O)

We use a Punnett square to determine the possible genotypes of their offspring:

| | O | O |
|-----|-----|-----|
| B | BO | BO |
| B | BO | BO |

From the Punnett square, all offspring will have the genotype BO, which corresponds to Type B blood.

Proportions of children's blood types:
- 100% Type B blood

Answer:
$$
\boxed{\text{100% Type B}}
$$

---

#### 4. A woman with type B blood (genotype AB) is married to a type B person (genotype BO). Show the cross. What proportion of their children will have?
- Mother's genotype: AB (Type AB)
- Father's genotype: BO (Type B)

We use a Punnett square to determine the possible genotypes of their offspring:

| | B | O |
|-----|-----|-----|
| A | AB | AO |
| B | BB | BO |

From the Punnett square, the possible genotypes and their corresponding blood types are:
- AB: Type AB
- AO: Type A
- BB: Type B
- BO: Type B

Now, we calculate the proportions:
- AB: 25%
- AO: 25%
- BB: 25%
- BO: 25%

Converting these to blood types:
- Type AB: 25%
- Type A: 25%
- Type B: 50% (BB + BO)

Proportions of children's blood types:
- Type A: 25%
- Type B: 50%
- Type AB: 25%
- Type O: 0%

Answer:
$$
\boxed{\text{Type A: 25%, Type B: 50%, Type AB: 25%, Type O: 0%}}
$$

---

Final Answers:

1. (a) $\boxed{AA \text{ or } AO}$
2. (b) $\boxed{BB \text{ or } BO}$
3. (c) $\boxed{OO}$
4. (d) $\boxed{AB}$
5. (3) $\boxed{\text{100% Type B}}$
6. (4) $\boxed{\text{Type A: 25%, Type B: 50%, Type AB: 25%, Type O: 0%}}$