ribosomes/cell walls are they organelles?

[gooperwooper]

just wondering! Sources seem to differ.

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[aLemon]

I wouldn't say ribosomes or cell walls are organelles. The definition of an organelle is a membraned enclosed body that serves to separate various internal metabolic reactions. For ribosomes, think about this. Both eukaryotes and prokaryotes have ribosomes but prokaryotes are characterized with no organelles. Since prokaryotes lack organelles, we can infer the that ribosomes would technically not be considered as one. Cell walls aren't bounded by a membrane and don't fit the the definition of an organelle.

Hope this helps!

Edit: There appears to be two definitions for an organelle, one being a membrane bound organelle or a non-membrane organelle. Usually when one refers to an organelle, it follows the membrane bound organelle definition.
reference: http://www.ivyroses.com/Biology/Organelles/Organelle-Functions.php

 

[Frank22]

Ribosomes definitely are organelles; the cell wall is more argumentative, with most identifying it as not an organelle, I believe.

 

[danchoi03]

I disagree. Ribosome is not an organelle. This is the reason why prokaryotic doesn't have any organelle but it does have ribosomes.

 

[Frank22]

I disagree. Ribosome is not an organelle. This is the reason why prokaryotic doesn't have any organelle but it does have ribosomes.

Prokaryotic organisms do not have membrane-bound organelles, but they most certainly do have organelles in the form of ribosomes.

Question 5 on the 2007 ADA practice test:

"What cellular organelles would you
expect to be absent from fungi?
A. Mitochondria
B. Lysosomes
C. Ribosomes
D. Golgi bodies
E. Chloroplasts"

The answer is E, meaning the test makers identify ribosomes as organelles.

Question 9 on the 2007 ADA practice test:

"Each of the following cell organelles have
a membranous structure EXCEPT one.
Which one is the EXCEPTION?
A. Golgi complex
B. Centrioles
C. Mitochondria
D. Lysosomes
E. Endoplasmic reticulum"

The answer is B. Centrioles are not membrane-bound, yet the test-makers identify them as organelles.

"Which is the smallest organelle in the
cell?
A. Golgi body
B. Nucleus
C. Mitochondrion
D. Ribosome
E. Chloroplast"

The answer is D, meaning the test-makers again identify ribosomes are organelles.

"Ribosomes are different from other organelles because they have no membrane around them that separates them from other organelles..."

http://classroom.synonym.com/four-things-make-ribosomes-different-organelles-16687.html

"A ribosome is a cell organelle. It functions as a micro-machine for making proteins."

http://bscb.org/learning-resources/softcell-e-learning/ribosome/

 

[DAT Destroyer]

just wondering! Sources seem to differ.

Ribosome is an Organelle. However, cell wall is outside the cell, therefore not an Organelle.

 

[electrax]

Ribosomes are organelles. Prokaryotes have no membrane bound organelles, and the ribosome does not have a membrane