A fertility clinic explains the assisted reproductive technologies to a group of students…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A fertility clinic explains the assisted reproductive technologies to a group of students. Four cases are given.
- A woman cannot produce an ovum, but her fallopian tubes and uterus are healthy. A donor gives an ovum. Which technique places the ovum in her fallopian tube?
- A zygote of one cell and an embryo of blastomeres are both formed in a dish. Where is each transferred?
- An embryo of blastomeres is formed in a dish. Where is it transferred?
- A husband cannot inseminate his wife. Which technique places his semen in the female tract?
Need a reminder? The key ideaShow
A zygote divides, and the number of blastomeres doubles at each division: after divisions. A zygote or an embryo of up to blastomeres goes into the fallopian tube (ZIFT). An embryo of more than blastomeres goes into the uterus. In GIFT, the ovum of a donor goes into the fallopian tube. If each cycle succeeds with chance , the chance of at least one success in cycles is .
The worked solution
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Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Given. Four cases.
Plan. Match each case to a technique, and use the rule of blastomeres.
Step 1. The donor ovum. GIFT, gamete intra fallopian transfer. The ovum goes into the fallopian tube, and fertilisation takes place in the body.
Step 2. The zygote and the -celled embryo. Both have blastomeres or fewer. Both are transferred into the fallopian tube (ZIFT).
Step 3. The -celled embryo. It has more than blastomeres, so it is transferred into the uterus.
Step 4. The husband. Artificial insemination (AI), in which the semen is placed in the vagina, or intra uterine insemination (IUI), in which it is placed in the uterus. These are not in the NEET text.
Answer: GIFT; both into the fallopian tube; the uterus; artificial insemination.
Check. In the first case fertilisation is in the body, and in the other cases the embryo is made in a dish, or the semen is placed in the female tract.
Watch out. ZIFT transfers a zygote or an embryo. GIFT transfers an ovum, a gamete.
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