Why do multi cellular organisms need spcialised cells?

Question

i need the info for an ssignment im doing

thnx its much appreciated

Answer 1

That is a really broad question but a quick answer would be that different parts of the organism cannot mix because then it would die, they need to be compartmentalized. For example, your stomach acid could digest/destroy most of the other tissues in your body if it wasn't kept in your stomach by the specialized cells of your stomach lining.  Different proteins are active in tissues that have an environment that allows them to be active.  This is governed by many things including pH, osmolarity etc.  A text book (biology or physiology) would be the best way for you to start getting info for your assignment, so hit the library!  Good luck :)

Also think of how an animals bodily waste needs to be kept separate from it's other organs etc.

How separate structures are needed for things like sexual repro in animals and even fungi.

For one cell to be different from another it will change which genes it is expressing, so it will have different proteins than another cell, thereby allowing to perform different functions. proteins are the key.  For example liver cells produce many proteins (enzymes) which breakdown toxins in animals, which muscle cells allow the animal to move which requires completely different enzymes.

Sorry this is so confusing but hopefully you can use this for something!

Answer 2

A multi-layered organism would require specialized cells to deal with whatever is adjacent (air, liquids, food, other cells with different functions such as motive cilia).  

Answer 3

this can be well understood by looking

at a unicellular organism for example bacteria.



1. when it needs nutrition it decompose the food and then absorb it but in multicellular organism each single cell can't directly take it's food by absorption so it need specialized cells in the form of organ system for example digestive system to digest the food and blood to distribute it to each single cell.

2. when bacteria need take oxygen and eliminte CO2 it simply can by diffusion but a multicellular organism can't so it need specialized organs for example lungs in us and gills in fishes.

3. bacteria can move by flagella but multicellualar organism needs special system to move for example muscular system in us.etc



all these example tell that speciall cells in multicellular organism are means by which internal enviroment interact with external enviroment.