You are on a jury to decide the following case: The Jones family claims that baby Jane, given to them at Ucsc Medical Hospital, does not belong to them and that baby Sara, who was presented to the Smith family, really belongs to the Jones family. The Jones allege that the babies were exchanged on 4/20 by the medical staff. The staff deny the allegation Blood group determinations show the following results: Ms. Jones = AB Mr. Jones = O Mrs. Smith = A Mr. Smith = O Baby Jane = A Baby Sara = O A and B are dominant over O and A and B are codominant to one another. Which baby belongs to which family? Sara: Jane: Human cells normally have 23 pairs of chromosomes. For each of the following stages state the number of DNA molecules present in a human cell. Metaphase of meiosis II Metaphase of meiosis I Anaphase of meiosis II Egg cell

Question #1

To know which baby belongs to who you need to draw both families Punnett squares.

Let's start with the Jones family. Mr. Jones is AB this means, he has co-dominant alleles. Ms. Jones is 0 this means, she has two recessive alleles.

When you draw the Punnett square, you'll find that chances are 50% group A, and 50% group B.

Now, analyze the Smith family Mr. Smith is group A this means, he has either two A alleles or A0. Ms. Smith is group 0 this means, she has two recessive alleles.

If Mr. Smith is AA, 100% of children will be A, and if Mr. Smith is A0, 50% of children will be group A, and 50% will be group 0.

Baby Jane is group A, she could be either Smith or Jones, but baby Sara is group 0 the only chance is that her family was the Smith.

Question #2

Meiosis is a process in which gametes create. You have two stages: meiosis I, and II. At the end of meiosis I, you still have diploids cells (2n) this means, you have a pair of chromosomes in each cell. At the end of meiosis II, you have all haploid (n) cells, with half of the genetic charge.

Metaphase of meiosis II: Sister chromatids are in the equatorial plane to be pulled apart without being replicated. Here you have 46 chromosomes about to create two cells with 23 (n) chromosomes.

Metaphase of meiosis I: homologs chromatids are in the equatorial plane to be pulled apart after replication. Here you have 46 pairs of chromosomes about to create two cells with 46 chromosomes each (2n).

Anaphase of meiosis II: all singles chromatids (n) are in the poles and the plasmatic membrane begins to close to obtain two haploids (23 chromosomes each) cells.

Egg cell is the result of meiosis II and is the breeding cell. Its chromosomic charge is 23.