Explain the terms : (i) Implantation of Zygote (ii) Placenta
Explain the terms : (i) Implantation of Zygote (ii) Placenta
(i) Implantation of Zygote: After fertilization in the fallopian tube, the zygote divides to form an embryo. This embryo moves into the uterus and gets attached to its thick, soft, and vascular lining. This attachment and embedding of the embryo in the uterine wall is called implantation.
(ii) Placenta: The placenta is a specialized disc-like tissue embedded in the uterine wall during pregnancy. It serves as a physiological connection between the mother and the fetus. It has villi on the embryo's side and blood spaces on the mother's side, providing a large surface area for the exchange of glucose, oxygen, and waste products.
Marking Scheme
- 1Explanation of Implantation (attachment of embryo to uterine wall) (1 mark)
- 2Explanation of Placenta (disc-like tissue for nutrient/waste exchange) (1 mark)
Hint
Recall how the embryo gets nutrition from the mother and where it stays for nine months.
Quick Oral Answer
Implantation is when the embryo sticks to the uterus wall. The placenta is the tissue that gives the baby food and oxygen from the mother's blood.
Analysis & Explanation
While the provided text snippet ends at plant fertilization, the canonical NCERT chapter explains that in humans, the lining of the uterus thickens every month to support a potential embryo. Implantation is the critical step that establishes pregnancy. The placenta is essential because the fetal blood and maternal blood do not mix directly; instead, nutrients and gases diffuse across the placental membrane.
Common Mistakes
- 1Saying the zygote implants (it is actually the embryo/ball of cells).
- 2Thinking maternal and fetal blood mix directly in the placenta.
Interesting Facts
The placenta is the only organ in the human body that is formed from two different genomes—partly from the mother and partly from the fetus.
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Frequently Asked Questions
How many marks does this question carry in CBSE Class 10 Science 2011?
This question carries 2 marks in the CBSE Class 10 Science 2011 examination.
Which chapter does this question come from in Science?
This question is from the chapter "How do Organisms Reproduce?" in the CBSE Class 10 Science syllabus.
What topic does this question cover in Science?
This question covers the topic "Human Reproduction" from CBSE Class 10 Science.
What type of question is this in the CBSE Class 10 Science 2011 paper?
This is a Short Answer question from Section A in the CBSE Class 10 Science 2011 paper.