Question
Explain the process by which zygote divides and redivides to form the morula.
✓
Answer
(1) Cleavage is a rapid mitotic division to form a blastula. These divisions takes place immediately after fertilization. The cells formed by cleavage are called blastomeres.
(2) The type of cleavage in human is holoblastic, i.e. the whole zygote gets divided, radial and indeterminate, i.e. fate of each blastomere is not predetermined.
(3) Cleavage show faster synthesis of DNA and high consumption of oxygen.
(4) Since there is no growth phase between the cleavages, the size of blastomeres will be reduced with every successive cleavage.
(5) The cleavages occur as follows:
(6) Successive divisions produce a solid ball of cells called morula of 16 cells. It consists of an outer layer of smaller clearer cells and an inner mass of larger cells.
(7) Morula reaches the uterus about 4-6 days after fertilization.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
What are the three types of endosperm? Describe them briefly.
Glottis is guarded by a flap called epiglottis.
Observe the given food web and answer the questions
1. Name the producers in the above web.
2. Name the primary consumers in the above web.
3. Which is an omnivore animal in the above web? Why?
4. Why frog is occupying an important ecological position in this web?
5. From the given food web diagram, give the trophic levels where the eagle is present.
1. Name the producers in the above web.2. Name the primary consumers in the above web.
3. Which is an omnivore animal in the above web? Why?
4. Why frog is occupying an important ecological position in this web?
5. From the given food web diagram, give the trophic levels where the eagle is present.
Transgenic plants.
Describe different ways in which epithelial surface offers the innate immunity.
Represent schematically the life cycle of a malarial parasite.
How many different types of gametes could result from each of the following genotypes? What will be their genotypes?
- Aa.
- AABB.
- AaBb.
- EeCc.
- FFIIJj.
Give an account of poultry diseases.
Packaging in Prokaryotes
You have a friend whose parents are too indulgent in his/her daily affairs. They think him/her to be still young which makes him/her sad and is upset all the time. As he/she feels that the parents should give him/her opportunity to take independent decision on some issues.
- Would you support your friend and why?
- Write the characteristics of this age group.
- List two curative measures.