Polyembryony is observed in plants like Mango.
Nucellar cells develop into the embryos.
Which of the following is true?
- Both (A) and (R) are true and (R) is the correct explanation of (A)
- Both (A) and (R) are true, but (R) is not the correct explanation of (A)
- (A) is true, but (R) is false
- (A) is false, but (R) is true
The Correct Option is A
Solution and Explanation
Top Questions on Pregnancy And Embryonic Development
In angiosperm, the haploid, diploid and triploid structures of a fertilized embryo sac sequentially are:
- NEET (UG) - 2023
- Biology
- Pregnancy And Embryonic Development
- In which month of gestation, the first movements of foetus and appearance of hair ion its head is observed?
- KCET - 2022
- Biology
- Pregnancy And Embryonic Development
- Match the months listed in Column-I with the organogenesis of foetus in Column-II.Choose the correct options :
Column-I
Column-II
(i) First month (a) Separation of eye lids (ii) Second month (b) Hairs on head (iii) Fifth month (c) Heart (iv) Six month (d) Limbs & digits - KCET - 2020
- Biology
- Pregnancy And Embryonic Development
- The amnion of mammalian embryo is derived from
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- Biology
- Pregnancy And Embryonic Development
- The amnion of mammalian embryo is derived from
- NEET (UG) - 2018
- Biology
- Pregnancy And Embryonic Development
Notes on Pregnancy And Embryonic Development
Concepts Used:
Embryonic Development
A successful pregnancy goes through several distinct stages. A man’s sperm must reach, penetrate, and fertilize a woman’s egg.
1. Fertilization
Fertilization is the association of the female gamete (egg) and the male gamete (spermatozoa). Whether it occurs naturally inside the female reproductive system or with the help of reproductive technologies outside of the human body. Further, the product is a structure called a zygote.
2. Blastocyst Development
After fertilization, the embryo is created from a small group of cells that are constantly splitting inside of a complex structure called the blastocyst. It is formed by two groups of cells, inner and outer cells, and fluids. The blastocyst remains inside a protective cover during maturation called zona pellucida, which could be described as an eggshell. The outer cells are located just below this cover, which will create the future placenta and surrounding tissues to support fetal development in the uterus.
3. Blastocyst Implantation
When the blastocyst outreach the uterus it implants in the endometrium, the mucus membrane which lines the uterus. The external cells of the blastocyst and the uterine inner lining, altogether, create the future placenta. A structure that transfers nutrients to the baby and removes his/her wastes is called the placenta.
4. Embryo Development
As the blastocyst reaches the final stage in the implantation process into the inner lining of the uterus, it evolves into a structure called an embryo. At this time, internal organs and external structures develop. The mouth, lower jaw, and throat are emerging, while the blood circulation system starts its evolution and a heart tube is created. The ears arise and arms, fingers, legs, toes, and eyes are being shaped. The spinal cord and the brain are already formed, while the digestive tract and sensory organs start their development. The cartilage is being replaced by the first bones.
5. Fetal Development
The embryo moves into the final stage of development by the twelfth week of fertilization, called the fetal stage. Till now, the fetus has formed all of the organs and structures that are necessary for a baby, but those organs still need to grow and develop.
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