13. Before mitosis begins, a human skin cell contains 46 chromosomes. When that
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Question
13. Before mitosis begins, a human skin cell contains 46 chromosomes. When that cell is at a metaphase stage of mitosis, how many chromatids does it contain? 6. What are the gametes formed by the following squash plants, and what will be the appearance of the offspring from each cross? a. WWdd x wwDD b. WwDd x Wwdd c. WwDD x wwdd d. WwDd x wwdd e. WwDd x WwDD f. WwDd x WWDd 7. Two normal appearing parents produce a child suffering from sickle-cell anemia. What is the chance that the next child will also have this anemia? 8. Suppose that a group of people decide to migrate to an uninhabited island. A serologist tests them and finds that they are assorted: 50 are type M 300 are type MN 150 are type N Are the blood types representative of a population in equilibrium? 9. Suppose two unrelated albinos married and had 8 children, 4 albino and 4 non-albino. How could you explain these results? 11. A normal man marries a normal woman known to carry the hemophilia gene (a carrier). Hemophilia will likely occur in what percentage of their mail children? 13. Before mitosis begins, a human skin cell contains 46 chromosomes. When that cell is at a metaphase stage of mitosis, how many chromatids does it contain? How many centromeres? At the conclusion of mitosis, how many chromosomes does each of the two daughter cells contain? How many centromeres? 16. Diagram all phases of mitosis in plant and animals noting all of the structural similarities and/or differences. 17. Determine the gametes produced by each of the following genotypes: d. AaBbCcDdEe e. Aabbccddeeff
Explanation / Answer
2) Ans: In a heterozygous genotype two gametes are produced, in homozygous genotype one gamete is produced.
a.) WWdd x wwDD : Gametes WW (1) dd (1) and ww (1) DD (1). 1* 1 + 1*1 . A total of two gametes are produced. Wd wD -----> Wd x wD ---> WwDd ( F1 offspring)
b.) WwDd x Wwdd : Gametes Ww (2) , Dd (2) / Ww (2) , dd(1). A total of (2*2 + 2*1) 6 gametes are produced.
WD Wd wD wd x Wd wd ----> offspring ( WWDD, WWDd, WwDD, Wwdd, WwDd, wwDD, wwDd, wwdd )
c.) WwDD x wwdd : Gametes Ww (2) DD(1) / ww (1) dd (1) . Total 3 gametes are produced. WwDD : WD wD / wwdd : wd -------> Offspring WwDd,, wwDd,
d.) WwDd x wwdd : Gametes WwDd : Ww (2), Dd (2)/ ww (1), dd(1) . Gametes are : WwDd: WD Wd wD wd : wwdd : wd
--------> Offspring WwDd , Wwdd, wwDd, wwdd
e). WwDd x WwDD : Gametes WwDd (2)* (2) / WwDD : (2) (1) . WwDd: WD Wd wD wd / WwDD : WD wD.
Offspring -------->WWDD, WWDd, WwDD, wwDD, WwDd, Wwdd, WWdd, wwDd, wwdd
f.) WwDd x WWDd : Gametes: WwDd: WD Wd wD wd / WWDd : WD Wd
Offspring ---------> WWDD, WWDd, WwDD, Wwdd, WWdd, WwDd, wwDD, wwDd, wwdd
6.) Hemophilia is an X-linked recessive disorder. A person with normal allele marries a carrier female. The genotype of the Male is XHY. The genotype of female is XHXh .
On Punnet square we identify the results:
25% of male children are with hemophilia.
9.) In heterozygous genoptype 2 gametes are produced, in homozygous genotype onw gamete is produced.
9.i) AaBbCcDdEe : ( 2) * (2) * (2)* (2)* (2) . So 32 gametes are produced. They are ABCDE, Abcde, ABcde, ABCde, ABCDe, AbCDE, ABcDE, ABCdE, AbCde, AbcDe, AbcdE, aBCde, aBcDe, aBcdE, abCDe, abCdE, aBCDE, abCDE, abcDE, abcdE, aBcde, abCde, abcDe, aBcDE, aBCdE, aBCDe, AbcDE, AbCdE, AbCDe, ABcdE, AbcDe, abcde.
9.ii) Aabbccddeeff : (2) * (1)* (1)* (1) *(1) *(1) = 2. Abcdef and abcdef.
WD Wd wD wd WD WWDD WWDd WwDD WwDd Wd WWDd WWdd WwDd Wwdd wD WwDD WwDd wwDD wwDd wd WwDd Wwdd wwDd wwddRelated Questions
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