organelles (both plant and animal)

[royboy]

hey there people need help wit my assignment. anyone got any idea on which is the most unimportant organelle in a cell? i mean one that u could get rid off and wouldnt make much of a difference?

[MrMistery]

centrioles.

[royboy]

wat exactly does the centriole do???

[Dustfinger]

They are relevant in the mitosis.

[rindishy]

centrioles ARE needed

[alcyon]

but some plants don't really have them though... why do some animal cells need them (if they really need them) and some plants don't?

[kotoreru]

You can remove the ribosomes from the rough endoplasmic reticulum and the cell will still function well, if I recall. I could be wrong though. Obviously you still need ribosomes in the cell though.

[alcyon]

some say that if a protein that will be transported out of the cell in the end is being made, it will first happen on a ribosome not attached to the ER, and then the already thynthesized part of the peptide chain will direct the ribosomes toward the ER; Yet some others has it that some ribosomes are permanantly attached to the ER and only these ribosomes produce protein that will be used outside of the cell...(sorry I forgot the word for 'proteins used outside of the cell' in English, so this get's a bit long)

[Darby]

It depends upon the cell.

For many body cells that will never divide again, like muscle cells, centrioles would work, but I don't think they persist anyway.

Cells don't tend to have a lot of extraneous parts - most guesses at this would include a certain amount of ignorance about the purpose of some organelles in some cells.

[MrMistery]

the function of centrioles is still unknown. plant cells lack them, and if you distroy them using a microlaser in an animal cell, the cell will still undergo mitosis. mitosis will work even without a centrosome at all, by the formation of what is known as a bipolar spindle.
i am not saying that centrioles have no function. the probably do, considering natural selection. however, it is not known yet.

ribosomes can attach and detach from the ER. protein synthesis always starts on free ribosomes in the cytoplasm. then once a part of the protein is synthetised(the signal sequence) a protein named the signal recognition particle attaches to the protein being made, stopping protein synthesis. then, the ribosome docks on the ER on a special multiprotein particle named a translocon. the process is complex, but the point is that ribosomes on the ER are not different from free ribosomes in the cytoplasm.

[alcyon]

Oh...so the ribosomes only attach to the ER during protein synthesis?

And, just wondering, where did u get such clear information from? My highschool text book said something really vague about this and when i tried to find out I didn't know where to look. Even some of the Uni texts only gave a fuzzy kind of outline.

[MrMistery]

well i wrote that from my memory. But if you want to study cell bio i recommend Alberts. It's free on pubmed http://www.ncbi.nlm.nih.gov/books/bv.fc ... OC&depth=2