Relationship between cell organelles

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pinkgurl192
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Relationship between cell organelles

Post by pinkgurl192 » Thu Feb 22, 2007 11:45 am

hi. this is my biology homework that i'm stumped at.
Describe the functional relationship between the NUCLEUS, ROUGH ENDOPLASMIC RETICULUM, GOLGI APPARATUS, RIBOSOMES AND LYSOSOMES.
please help me!

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MrMistery
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Post by MrMistery » Thu Feb 22, 2007 12:34 pm

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Post by sonken » Thu Feb 22, 2007 1:21 pm

nucleus: control center
lysosome: waste treament center
rough ER: production center
Golgi: processing and package center
Ribosome is not an organelle since it is not bound by the membrane structure, and it can be produced de nove.i.e it doesn't need the pre-existing ribosome to regenerate.

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Post by MrMistery » Thu Feb 22, 2007 3:18 pm

Ribosomes are organelles, but not membrane-bound organelles.
And all organelles except for mitochondria and plastids cand be produced de novo. At cell division all the organelles except those mentioned above desintegrate and are later reproduced.
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Post by sonken » Fri Feb 23, 2007 7:27 am

sorry, i don't agree with what you said.

The definition of organelle: membrane-enclosed compartment that has distinct structure, macromolecular composition and functions. Accoding to this version of definition, ribosome is not organelle.

All organelles cannot be generated de novo.
Mitochondrion and chloroplast generate themselves by fission. Other organlles: ER, Golgi, peroxisome, lysosomes generate by adding protein and other chemical to the existing ones then the enlarged organelle is divided into 2 or more new organelles.

For ribosome, the risomal protein is synthesized in the cytosol, then it is imported into nucleus, conbine with rRNA and form ribosome, finally it is exported out. thus it doesn't the pre-existing ribosome to regenerate itself.

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MrMistery
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Post by MrMistery » Fri Feb 23, 2007 10:59 am

The definition of an organelle from Biology 7th edition by Neil Campbell and Jane Reece: one of several formed bodies with specialised functions suspended in the cytoplasm
The same book defines ribosomes as "nonmembranous organelles that make proteins; free in the cytoplasm or bound to rough ER or nuclear envelope.

Life 7th edition by Sadava, Purves et all says at protein synthesis: "Although ribosomes are large in contrast to other cellular organelles, their mass makes them larger than tRNAs" - implying of course that they too are organelles. Also, the same book defines ribosomes in the glossary at the end as "a small organelle that is the site of protein synthesis"

Molecular Biology of the cell 4th edition by Alberts et all seems to agree with you. They define organelle as "membrane bound vesicle in the cytoplasm of eukaryotic cells", while defining a ribosome simply as a "supramolecular machiene".

From my understanding of the matter, ribosomes are considered organelles because they serve a vital role in protein synthesis, regardless of the fact that they have no membrane.

But still.. At the cell division the endomembrane system disociates, doesn't it? And then reasociates. that is how i know it.

Anyway, if you want, accept the definition of organelle as membrane bound. I don't think anyone will mind.
Regards,
Andrew
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Post by Poison » Fri Feb 23, 2007 10:12 pm

I agree with Andrew.
Ribosomes ARE organelles but not membrane bound.
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