The correct answer is "thoracic duct".
The thoracic duct (also called as the left lymphatic duct or the alimentary duct) is the structure wherein most of the lymph in the drained from the lymphatic vessels goes to this structure. In the thoracic duct, lymph flows up to the level of the brachiocephalic vein where lymph returns to the venous circulation.
The UV rays cause sun spots due to reaction from the radiation.
A is true because they do have a true nucleus or membrane-bound organelles .
Answer:
B. The father did not contribute a sex chromosome to his daughter due to nondisjunction of the sex chromosomes. The daughter is XO and her only X chromosome came from her mother, who was a carrier.
A.The mother's X chromosomes failed to separate during meiosis, and the daughter inherited two X chromosomes with the Lesch-Nyhan mutation. The father contributed no sex chromosomes.
Explanation:
As seen in the question above, a little girl was diagnosed with Lesch-Nyhan syndrome, which is an X-linked recessive condition caused by a mutation in the HPRT1 gene responsible for purine metabolism.
The little girl's parents do not have the syndrome, and no one in the little girl's paternal family presented this syndrome, however, we know that the maternal grandfather of the little girl's mother had the syndrome, which means that it was the mother's genetic material that contributed to the development of the syndrome in the little girl. This was because the little girl did not receive any X chromosomes from her father, but she inherited the two X chromosomes from her mother that coded for the Lesch-Nyhan mutation. This happened because the mother's X chromosome disjuction did not occur during meiosis I.
As shown above, the father did not contribute any sex chromosomes to his daughter, which means that the daughter is XO and her only X chromosome came from her mother, who was a carrier.
Answer:
Pleiotropy
Explanation:
Pleiotropy is a genetic condition in which a single gene conditions the expression of multiple phenotype. There are different types of pleiotropy depending on the underlining mechanism
- <em>gene pleiotropy</em>
- <em>developmental pleiotropy</em>
- <em>selectional pleiotropy</em>
- <em>antagonistic pleiotropy </em>
<em>Phenylketonuria is a disease characterized by increased level of amino acid phenylalanine in the blood. It caused by mutation to the gene responsible for breaking down phenylalanine in the blood. Elevated level of phenylalanine causes other issues such as mental problems, urine coloration and reduction in skin pigmentation. This is a clear case of pleiotropy.</em>
