1. A Rh negative woman gives birth to her first child who is Rh positive with no
ID: 10330 • Letter: 1
Question
1. A Rh negative woman gives birth to her first child who is Rh positive with no complications. When she becomes pregnant with her second child, her doctor gives her an injection of Rh immunoglobulin (RhIg).a.Why did her doctor inject her with RhIg?
b.Why did she receive RhIg for the second pregnancy but not the first?
2. During a biology lab activity the class is asked to look for Barr bodies in their cells. David, a male class member, identifies Barr bodies in his cells.
a.What is David’s likely genotype?
b.What mechanism causes this condition?
3. A scientist has cloned a calico cat, but the clone’s coat pattern looks nothing like the original cat’s coat even though they share identical DNA and were raised in identical environmental conditions. Knowing that the gene for coat color is on the X chromosome, explain why these two genetically identical cats do not share the same phenotype.
4.The allele for a Widow’s peak hairline is dominant over the allele for a straight hairline. Based on this information it can be assumed:
a.A Widow’s peak hairline would be more present (higher frequency) in any human population
b.A Widow’s peak hairline is the “wildtype” hairline c. A Widow’s peak hairline is due to a mutation in the hairline gene d. None of the above can be assumed about a dominant allele
5. A scientist who is studying human genetics has noticed that people who can roll their tongues (a genetically controlled trait) also have hair on the second knuckle of their middle finger (a genetically controlled trait).
a.Based on this information, what can the scientist infer about these two traits?
b.Out of the 1000 people the scientist evaluated for these traits, five people had one of the traits, but not the other. In this case the phenotype is not caused by a mutation. What is most likely causing the atypical phenotype in these five people?
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6. Angela has blood type A- and is an about to have major surgery that will require a blood transfusion. (a) List all types of ABO/Rh blood types she can receive.
(b) After she heals from the surgery, Angela decides to donate blood. Name all blood types that would be able to accept Angela’s blood.
7. In blood transfusions, ______ is known as the universal donor, while _____ is the universal recipient.
8.Would it be possible for a father with B+ blood and a mother with A+ blood to make a child with O- blood? If so, list the possible genotypes of each family member.
9. Would it be possible for a father with B- blood and a mother with A- blood to make a child with O+ blood? If so, list the possible genotypes of each family member.
Explanation / Answer
1.a. The doctor injected her with Rh immunoglobulin as she is a Rh- lady with Rh+ antibodies in her blood stream. The Rh+ antibodies were formed during the first pregnancy and delivery. If she is not injected with RhIg and if the baby is Rh+, these Rh+ antibodies will enter the fetus and destroy the baby. b. When the first Rh+ baby is in the womb of a Rh- mother, Rh+ antibodies are slowly formed in the mother. In the second delivery, if the baby is again Rh+, these antibodies will attack the baby. That's why the RhIg is given for the second pregnancy and not the first. ------------------------------ 2.a. David's likely genotype is XXY. b. The cause for this condition is an abnormal egg or sperm. If the egg has two X chromosomes or the sperm had XY chromosomes, this would result in this condition of having an extra chromosome. ---------------------------------- 3. This phenomenon is due to X chromosome inactivation. So, this shows that the cat did not have a homozygous genotype. Both the donor and the clone had different X chromosomes inactivated. This lead to the difference in phenotype seen in the cats. --------------------------------- 4.The answer is "a" ------------------------------------ 5. a. These two traits pertain to linked genes b. As very few people possess the atypical phenotype, we can say that they are recombinants seen after cross-over between the two linked genes. The low number of recombinants indicate that the distance between the linked genes is very less. ----------------------------- 6.a. She can get A- and AB- b. The receipients can be O- and A- ----------------------------- 7. O is the universal donor and AB is the universal rceipient ---------------------------- 8. Yes the child can be O-. The parents genotype can be B+O- and A+O-. ----------------------------- 9. Yes the child can be O+. The parents genotype can be B-O+ and A-O+.Related Questions
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