Question

a- What is the function of centrioles in sperm? b- Please write and explain in detail the polyp and medusa stages of Obelia.

Answer 1

After reading some books,I think :

Question 1:

What is the function of centrioles in sperm?

We all know that centriole is a type of organelles which is surrounded by the plasma membrane, it is a small cylindrical like structure which generally presents near cytoplasm of the cell . It involves cell division by moving to the opposite poles of the cell.

It also plays a key role in sperms just like :

I) It helps in the formation of sperm flagellum and also helps sperm movement at the time of fertilization by it carring sperm into the fallopian tube

II)Centriole helps in the development of the embryo in the fertilization process and also helps in the formation of centrosome and microtubule of the zygote.

Question 2:

Please write and explain in detail the polyp and medusa stages of Obelia.

The polyp is a type of abnormal tissue which generally present in the colon for about 25% of men and women aged 50 and up . Basically, polyps are harmless and fat-enriched foods and red meats are the best preventives of polyp but according to some research, after 10-year polyp may turn into malignant from small adenoma ,that's why we need to do the colonoscopy in every 10 year for 50+ aged people.Although polyp present in the colon it may be present in the ear canal and cervix.

Obelia is a type of organism which generally present in the freshwater , it has polyp and medusa (reproduction) stages in their life . Generally, Obelia is a genus from the hydrozoans and phylum from Cnidaria.

One of the most important stages of obelia is medusa basically it is the reproduction stage ,we all know that obelia is a marine organism which means it has good swimming adaptability and at the time of swim obelia releases either eggs or sperms and in the fertilization the resultant zygote formes in a huge number , but this new resultant zygote is covered by cilia or tiny hair-like structure and certain times this zygote changes into a polyp and from that mature obelia born . The most important thing about obelia is it can reproduce asexual as well as sexual , this whole reproduction stage is called as medusa