Question

According to my book, "the Golgi body of a cell is an organelle involved in protein modification and subcellular localization."

1) Why do proteins need to be modified?

2) Does the "subcellular localization" part I quoted above mean that the Golgi body is responsible for keeping the organelles of the cell separate? Are there "functionally distinct membrane-bound compartments" that are not organelles?

Any input would be GREATLY appreciated!

Answer 1

For #2 the emphasis is on the word "organelles".

Answer 2

lets think of proteins
what do u think? why do they need to be modified?

Answer 3

for different somatic cells?

Answer 4

That is, to be used in the making of different somatic cells?

Answer 5

no
do you know anything about so called signaling?

Answer 6

proteins need to be modified and there are different types of modifications
in some its addition of non protein group to the polypeptide chain
in some it is removal of some of peptides from the polypeptide chains

Answer 7

no, i'm not in health sciences. i'm taking a complementary course (willingly :P)

Answer 8

to be short
proteins need to be modified to KNOW where to do
for example lets say golgi received hydrolitic enzymes that are required to be passed on to LYSOSOME and NO OTHER ORGANELLE
so there enzymes/poplypeptides need to have a particular 'destination' for themselves
and these modifications help to target where the polypeptides are supposed to go to

Answer 9

so like if we need to send a protein to plasma membrane
then that protein will have to be modified/ some group added to it to target ONLY PLASMA MEMBRANE
and thus when the protein is released in a vesicle from golgi - it can directly go to plasma membrane and definitely not to any other destination

Answer 10

does it make sense?

Answer 11

thats one of the reasons modification needs to be done
another one is that these modifications can actually control the 'life span' of proteins

Answer 12

Did you mean to say that proteins need to be modified to go through the membrane of a certain organelle (and no other organelle than the intended one)?

Answer 13

no no
more like they need to be modified to KNOW where to go to
if the destination of the polypeptide is lysosome -it'll go to it and enter it
and it won't go to plasma membrane of the cell or to mitochondria or to nucleus or to any other organism

Answer 14

you kind of right but you need to mention the target and thats not always organelle

Answer 15

like you can get some proteins out in cytoplasm
if protein is to be there

Answer 16

but yeah i think you got the idea :)

Answer 17

Yes, I think so too (for #1). :)

Answer 18

What about #2?

Answer 19

hmm i think its to do with proteins and their locations within cell

Answer 20

its like when the modification is done
the protein is sent to a particular location

Answer 21

again you can bring up lysosome
targeted location for hydrolitic enzymes - is lysosome

Answer 22

Okay so the Golgi body modifies a protein, giving it a destination, and, then, using the mechanism of sub-cellular localization, sends the protein to the destination that was given to it?

Answer 23

yep pretty much tho subcellular localization is more like instruction rather than mechanism
you see, its all interconnected
for a protein to know where to go
it needs to be modified
but for it to be modified - it needs to first know where to go/know its location within the cell

Answer 24

Okay, so to re-phrase it myself:

Step I: The Golgi body first determines where to send the protein.

Step II: The Golgi body modifies the protein so that it knows its destination.

Answer 25

bingo! :)

Answer 26

Yay. :)

Answer 27

regarding 'Are there "functionally distinct membrane-bound compartments" that are not organelles?'
yes there are

Answer 28

like vesicles - they are not organelles but are surrounded by lipid membrane

Answer 29

and are considered to be membrane bound compartment

Answer 30

Ok, so is the following statement 100% correct?:
"The cells of eukaryotic organisms are elaborately subdivided into functionally-distinct membrane-bound compartments, where these membrane-bound compartments are not all organelles. This functionally-distinct membrane-bound compartmentalization is known as sub-cecullar localization."

Answer 31

hmmm compartmentalization is formation of cellular compartments so it refers to these compartments to be the locations then its correct

Answer 32

but im not sure if it does refer to it - that last sentence 'This functionally-distinct membrane-bound compartmentalization is known as sub-cecullar localization'

Answer 33

this one doesn't sound right to me to be honest
coz when we say 'compartmentalization' - we mean the formation of compartments
while subcellular localization is refereed to location

Answer 34

How about this? Is this 100% correct?:
"The cells of eukaryotic organisms are elaborately sub-divided into functionally-distinct membrane-bound compartments, where these membrane-bound compartments are not all organelles. This sub-division is known as sub-cecullar localization."

Answer 35

no
more like
these subdivisions/ compartments are the distinct locations to which a cargo is to be sub-cellularly localized
or something like that
instead of cargo 'protein' fits perfectly

Answer 36

sub-cellular means within cell so it sounds more correct if we put it that way

Answer 37

Okay so this is 100% correct?:
"The cells of eukaryotic organisms are elaborately sub-divided into functionally-distinct membrane-bound compartments, where these membrane-bound compartments are not all organelles. These sub-divisions/compartments are the distinct locations to which a protein is to be sub-cellularly localized."

Answer 38

Also, is it only proteins that are sub-cellularly localized?

Answer 39

well not really
i guess cargo is better now lol
write cargo instead hmm

Answer 40

actually, i'm falling apart now, it's too late. i'll continue this tomorrow.

Answer 41

thank you very much for your help, though.

Answer 42

bye and goodnight if it's night there too :)

Answer 43

no problem :))) good night for u :) & morning for me lol