Question

in angiosperm for the formation of 12 three celled male gametophyte from microspore mother cell how many meiotic and mitotic division are required ?

Answer 1

Let's start with first bunch of cell forms inside epidermis and then at the four corners some cell could be easily differentiate from others i.e archesporial cells. In that two type of cells formed 1)- primary parietal cell 2)- primary sporogenous cell

Primary sporogenous cell convert into sporogenous cell by doing mitosis and then sporogenous cell differentiate into microspore mother cell.

Now microspore mother cell do meiotic division and form 4 microspores.

Now, the nucleus within the microspore divide mitoticaly and form big vegetative nuclie and other one small generative nuclie.

Now, after cytokinesis this two cell stage we can called partially developed male gametophyte or pollen grain. And this is stage where more than 50% of angiosperms did their pollination.

Now, on stigma of flower pollen grain start forming the pollen tube by absorbing the moisture and sugar content and now generative cell after entering in the pollen tube divide mitoticaly and form two non motile male gametes.

And this three cell stage now we called mature male gametophyte which is highly reduced and completely depends on sporophyte.

So, coming to your question it totals to about 1 meiosis and 2 mitosis for male gametophyte but for female gametophyte 1 meiosis and 3 mitosis.

Answer 2

Explanation:

Multi-cellular organisms depend on both 'hormones' as well as 'electrical impulses' for the 'transmission'. These hormones and electrical impulse act as a medium of information transformation to the various cells to undergo the biochemical pathway.  

They are the basis for the information distribution or transmission to various body parts for the activity to initiate and necessary progress to be done. They are done by two transport method, the active and passive transport.