A Human Development

Write a short answer for each of the following questions.

1. The acrosome of a sperm contains hydrolytic enzymes. Using your knowledge, what is the purpose of these enzymes?

2. Ectopic pregnancies occur in the uterine tubes or pelvic cavity. Explain how this can occur.

3. Amniocentesis is a test conducted on fetal cells found in amniotic fluid to determine whether the fetal cells havegenetic abnormalities. Amniocentesis is usually conducted at 12 weeks. Amniotic fluid is collected by inserting a needle into the mother’s abdomen. List the structures the needle must go through to collect the amniotic fluid.

4. Are the cells obtained for culture from amniocenteses most likely derived from ectoderm, mesoderm, or endoderm?Explain your answer.

5. Chorionic villi sampling (CVS) is a test to determine whether fetal cells have genetic abnormalities and can beperformed as early as 8 weeks. Chorionic villi cells are removed using a small tube that is passed through the cervix.These cells are cultured and undergo chromosomal analysis. Explain why chorionic villi cells will determine whetherthe fetus has genetic abnormalities.

6. Drinking alcohol during pregnancy can lead to fetal alcohol syndrome, a condition that can cause heart defects, damage to the central nervous system, deformed limbs, slow growth, and abnormal facial features. Explain how theingested alcohol is transferred from mother to fetus.

7. Early pregnancy tests used antibodies to detect the presence of human chorionic gonadotropin (hCG) in maternalurine. Explain how hCG, produced by the chorion, gets in maternal urine.

8. Human embryonic stem cell research uses stem cells cultured from the blastula. These cells are pluripotent, meaningthat these stem cells can develop many different types of human cells. Identify the part of the blastula that they areusing and explain your choice.

9. During an ultrasonography, the doctor observes that all four chambers of the fetal heart are developed normally andthat blood can be observed passing from the right atrium to the left atrium. Explain why it is normal for blood to passfrom the right to left atrium in the fetal heart.

10. Placenta previa (previa = before or in front of) is a condition in which either part or the entire placenta implants inthe inferior part of the uterus near the cervix. Explain why this can cause spontaneous abortion or premature birth.

Heredity


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