The packaging, transport, import and export of protein

[Smiley_]

Hi I'm having a little bit of trouble with this concept could someone see if my notes are sufficient?

Starts at Nucleus
 transcription, = where the coded information for the construction of the protein is copied from a DNA template strand into mRNA (messenger RNA):
rRNA travels into cytoplasm at atttaches to ribosomes (free or on ER)

 translation= where the mRNA codons are decoded into a polypeptide chain consisting of a specific sequence of amino acids using complementary tRNA (in lots on 3 for a codon)

Transporting and processing – endoplasmic reticulum
Proteins synthesized by RER are further modified in Golgi apparatus and then packaged in vesicles for export from cell


Transporting and processing – endoplasmic reticulum (extensive network of interconnected membranous sacs and tubules branching throughout cell and can be smooth or rough)

Endoplasmic reticulum – extensive network of interconnected membranous sacs and tubules branching throughout cell and can be smooth or rough

Proteins synthesized by RER are further modified in Golgi apparatus and then packaged in vesicles for export from cell
Packaging – Golgi apparatus (stack of cisternae and matrix that encompasses it)

They are exported by the Vesicles in exocytosis.

[psyxwar]

(Additions I've made are in italics/ bold)

Hi I'm having a little bit of trouble with this concept could someone see if my notes are sufficient?

Starts at Nucleus
 transcription, = where the coded information for the construction of the protein is copied from a DNA template strand into mRNA (messenger RNA):

The "pre-mRNA" as it is called (the mRNA transcribed off the DNA template strand) is first spliced to remove the non-coding regions (introns) leaving the coding exons which join together

mRNA travels into cytoplasm at atttaches to ribosomes (free or on ER)

 translation= where the mRNA codons are decoded into a polypeptide chain consisting of a specific sequence of amino acids using complementary tRNA (in lots on 3 for a codon)

You might want to mention complementary tRNA triplets are known as anticodons. tRNA provide the amino acid building blocks for the growing polypeptide chain

Transporting and processing – endoplasmic reticulum
Proteins synthesized by RER are further modified in Golgi apparatus and then packaged in vesicles for export from cell

Whilst true, proteins can also be modified in the Rough ER itself (eg. glycosylation (the addition of carbohydrate groups to form glycoproteins) happens in the Rough ER

Transporting and processing – endoplasmic reticulum (extensive network of interconnected membranous sacs and tubules branching throughout cell and can be smooth or rough)

Endoplasmic reticulum – extensive network of interconnected membranous sacs and tubules branching throughout cell and can be smooth or rough

What's the function of the smooth and rough endoplasmic reticiulum?

Proteins synthesized by RER are further modified in Golgi apparatus and then packaged in vesicles for export from cell
Packaging – Golgi apparatus (stack of cisternae and matrix that encompasses it)

They are exported by the Vesicles in exocytosis.

[alondouek]

Regarding pre-mRNA, keep Unit 4 theory for Unit 4; they don't expect you to be discussing RNA splicing in Unit 3.

[psyxwar]

Regarding pre-mRNA, keep Unit 4 theory for Unit 4; they don't expect you to be discussing RNA splicing in Unit 3.

There's no midyears this year so I thought it'd help to know about it now.

[alondouek]

There's no midyears this year so I thought it'd help to know about it now.

Fair enough, but it's not really relevant until you start to look at protein synthesis from a genetics point of view. That said, learn whatever you can

Also, the person at VCAA who thought it would be a good idea to cut out mid-years is quite possibly the worst person in Australian education's history.

[psyxwar]

Fair enough, but it's not really relevant until you start to look at protein synthesis from a genetics point of view. That said, learn whatever you can

Also, the person at VCAA who thought it would be a good idea to cut out mid-years is quite possibly the worst person in Australian education's history.

Yeah I see what you mean. Still, doesn't hurt!

Oh I agree entirely... I'm so jealous of you guys who did it pre-2013.

[thushan]

Also, the person at VCAA who thought it would be a good idea to cut out mid-years is quite possibly the worst person in Australian education's history.

Actually, for some reason I like the idea.

And between you and me - Victoria has it quite lucky. The other states have only one end of year exam, which is 3 hours long. Least ours is only 2.5 hours.

[Smiley_]

(Additions I've made are in italics/ bold)
(Image removed from quote.)

thanks 

[Yacoubb]

Hi I'm having a little bit of trouble with this concept could someone see if my notes are sufficient?

Starts at Nucleus
 transcription, = where the coded information for the construction of the protein is copied from a DNA template strand into mRNA (messenger RNA):
mRNA travels into cytoplasm at attaches to ribosomes (free or on ER)

*When the DNA template is copied, a pre-mRNA molecule is made.
*The pre-mRNA is made up of exons (code for amino acids) and introns (do not code for amino acids).
*Splicing takes place and the introns are removed, leaving behind an mRNA molecule that codes for specific amino acids.

 translation= where the mRNA codons are decoded into a polypeptide chain consisting of a specific sequence of amino acids using complementary tRNA (in lots on 3 for a codon)

*The codons on the mRNA strand (three concurrent mRNA nucleotides) will form the primary structure of the desired protein when tRNA anti-codons carrying an amino acid complement an mRNA codon. For instance - UAC is the mRNA codon; the anti-codon carrying an amino acid would have the nucleotide sequence AUG (complementary).
* The tRNA molecule carries the amino acids to the free ribosomes/rough endoplasmic reticulum and a polypeptide is synthesised in the condensation reaction.
* The amino acids are joined together by strong peptide covalent bonds, and bondings of ionic, hydrogen and (sometimes) Disulfide bridges form, and the polypeptide is synthesised.

Transporting and processing – endoplasmic reticulum
Proteins synthesized by (RER? - always be clear and say Rough Endoplasmic Reticulum) are further modified in Golgi apparatus and then packaged in vesicles for export from cell

* It is handy to keep in mind that any protein that is synthesised to function within the intracellular aqueous environment of a cell is synthesised in free ribosomes.
* Any proteins that will be secreted to function outside the cell it is synthesised in, is actually synthesised in the ROUGH endoplasmic reticulum - don't use ER or RER.

Transporting and processing – endoplasmic reticulum (extensive network of interconnected membranous sacs and tubules branching throughout cell and can be smooth or rough)

Endoplasmic reticulum – extensive network of interconnected membranous sacs and tubules branching throughout cell and can be smooth or rough

When referring to the protein synthesis/secretion process, knowing that the Rough Endoplasmic Reticulum synthesises and transports proteins within a cell is adequate.

Proteins synthesized by RER are further modified in Golgi apparatus and then packaged in vesicles for export from cell
Packaging – Golgi apparatus (stack of cisternae and matrix that encompasses it)

When the proteins are introduced to the Golgi Complex, the proteins undergo modification. This modification enables the material to undergo a conformational change where they can be packaged into vesicles.

The vesicles bud off the complex and then leave the cell by bulk transport (exocytosis), and entering the Extracellular Matrix (interstiatial fluid and then blood plasma).

They are exported by the Vesicles in exocytosis.

Great set of notes though Good job!