Can someone explain gene expression??

[mathu2112]

Hey! In the elective topic Genetics Code broken, i dont get this dot point on the current understanding of the gene expression. Ca someone explain what we need to know and what gene regulation is?

[studybuddy7777]

I am not sure not having done the option myself, but is it just the same as blueprint of life or do you need to know it in more depth? Because if it is like the gene expression in blueprint, ill attach some notes. If not, someone else will come and help you. Ill just get this thread moving.

I hope this website helps its the one i use for all my bio and senior science (and yr11 chem) when i get stuck

http://dc.edu.au/hsc-biology-genetics/#Process_information_from_secondary_data_to_outline_the_current_understanding_of_gene_expression

Good luck and all the best its syl pt 2.3

[CinnamonTea]

Hi, gene expression is not really a difficult topic:
It is where the DNA code for a gene is switched on so it could produce a polypeptide which controls a particular function and structure.
It is important because if the Gene is expressed normally, the cell would function normally and hence tissues will be repaired and maintained .
Example is muscular dystrophy which is a sex linked disease
It is when the gene responsible for the protein dystrophine is mutated. Dystrophine is vital for muscle development and hence the disease leads to muscle degeneration and eventually death

[heids]

Edit: soz, a simpler explanation can be found here

I don't know how much depth you need it in, but gene expression is the process where the cell uses its DNA instructions (genes) to build its proteins.  There are two steps:
1.  Transcription, like photocopying those instructions
2.  Translation, like following the photocopied instructions to build the proteins.

Transcription
Transcription copies the genetic instructions from the DNA to make a portable copy, called messenger RNA (mRNA).  We use the enzyme RNA polymerase to make our RNA ‘photocopy’.  First, RNA polymerase unwinds the DNA.  Free RNA nucleotides bind to their complementary DNA nucleotides in the DNA template strand.  Then RNA polymerase sticks these RNA nucleotides together in a 5’ to 3’ direction to make an RNA strand, called a pre-mRNA strand.  It’s complementary to the original DNA template strand.  Then we ‘edit’ that pre-mRNA photocopy to make the final mRNA copy (chop out chunks called exons and leave in chunks called introns, and chuck bits on either end of the mRNA)

Translation
This step is like translating Morse code into English.  The mRNA code is like a morse-code message, where a certain number of dots and dashes are translated into an English letter.  The same way, each group of three nucleotides in the mRNA strand (e.g. AAA or GGC, and called a codon) is translated into one particular amino acid.
1.   The photocopied instructions, mRNA, are taken to the protein-making factory, the ribosome.
2.   Another type of RNA, transfer RNA (tRNA), has an amino acid attached to one end, and a group of three nucleotides (an anticodon) at the other end.  Each particular anticodon corresponds to a particular amino acid.
3.   Each tRNA anticodon binds to its complementary mRNA triplet codon. 
4.   The amino acids the tRNA molecules are carrying detach from the tRNA and bind together to form a polypeptide chain.
5.   One tRNA molecule, corresponding to the mRNA codons UAG, UAA and UGA, carries no amino acid.  When it binds to the mRNA, the polypeptide chain stops.
6.   The chain is folded into a specific 3D shape, a protein.

Gene regulation
Every single cell in our body has exactly the same genes; we have all the instructions to make every sort of protein needed.  But, based on their specific role, each cell only builds certain proteins.  Cells only express the genes that are ‘switched on’, and don’t express those that are ‘switched off’.  A type of protein called a ‘transcription factor’ makes it easier or harder for RNA polymerase to bind to the DNA at the promoter region (a section of DNA that starts transcription of a particular gene, upstream or to the 3’ end of the transcription start site).

Transcription factors are produced or activated in two ways:
1.   Regulator genes: we have two types of genes – structural genes, which produce the proteins involved in our structure and function, and regulator genes, which produce these transcription factors which control the action of other genes.
2.   External signalling molecules, like hormones; when they bind to cell receptors, they activate or inactivate transcription factors.

If an activated transcription factor makes it easier for RNA polymerase to bind to the promoter region, then transcription will occur, and the cell will express the protein.  But if the factor makes it harder for RNA polymerase to bind, transcription won’t occur, and the cell won’t express the protein.

Hope that helps

[vox nihili]

Edit: soz, a simpler explanation can be found here

I don't know how much depth you need it in, but gene expression is the process where the cell uses its DNA instructions (genes) to build its proteins.  There are two steps:
1.  Transcription, like photocopying those instructions
2.  Translation, like following the photocopied instructions to build the proteins.

Transcription
Transcription copies the genetic instructions from the DNA to make a portable copy, called messenger RNA (mRNA).  We use the enzyme RNA polymerase to make our RNA ‘photocopy’.  First, RNA polymerase unwinds the DNA.  Free RNA nucleotides bind to their complementary DNA nucleotides in the DNA template strand.  Then RNA polymerase sticks these RNA nucleotides together in a 5’ to 3’ direction to make an RNA strand, called a pre-mRNA strand.  It’s complementary to the original DNA template strand.  Then we ‘edit’ that pre-mRNA photocopy to make the final mRNA copy (chop out chunks called exons and leave in chunks called introns, and chuck bits on either end of the mRNA)

Translation
This step is like translating Morse code into English.  The mRNA code is like a morse-code message, where a certain number of dots and dashes are translated into an English letter.  The same way, each group of three nucleotides in the mRNA strand (e.g. AAA or GGC, and called a codon) is translated into one particular amino acid.
1.   The photocopied instructions, mRNA, are taken to the protein-making factory, the ribosome.
2.   Another type of RNA, transfer RNA (tRNA), has an amino acid attached to one end, and a group of three nucleotides (an anticodon) at the other end.  Each particular anticodon corresponds to a particular amino acid.
3.   Each tRNA anticodon binds to its complementary mRNA triplet codon. 
4.   The amino acids the tRNA molecules are carrying detach from the tRNA and bind together to form a polypeptide chain.
5.   One tRNA molecule, corresponding to the mRNA codons UAG, UAA and UGA, carries no amino acid.  When it binds to the mRNA, the polypeptide chain stops.
6.   The chain is folded into a specific 3D shape, a protein.

Gene regulation
Every single cell in our body has exactly the same genes; we have all the instructions to make every sort of protein needed.  But, based on their specific role, each cell only builds certain proteins.  Cells only express the genes that are ‘switched on’, and don’t express those that are ‘switched off’.  A type of protein called a ‘transcription factor’ makes it easier or harder for RNA polymerase to bind to the DNA at the promoter region (a section of DNA that starts transcription of a particular gene, upstream or to the 3’ end of the transcription start site).

Transcription factors are produced or activated in two ways:
1.   Regulator genes: we have two types of genes – structural genes, which produce the proteins involved in our structure and function, and regulator genes, which produce these transcription factors which control the action of other genes.
2.   External signalling molecules, like hormones; when they bind to cell receptors, they activate or inactivate transcription factors.

If an activated transcription factor makes it easier for RNA polymerase to bind to the promoter region, then transcription will occur, and the cell will express the protein.  But if the factor makes it harder for RNA polymerase to bind, transcription won’t occur, and the cell won’t express the protein.

Hope that helps

Great explanation, just one teeny tiny thing. It's actually introns that are taken out and exons that are left in.

Because introns are in the way and exons are expressed

[studybuddy7777]

Great explanation, just one teeny tiny thing. It's actually introns that are taken out and exons that are left in.

Because introns are in the way and exons are expressed

I like your thinking!! I'll have to remember that one :p 👍🏼

[heids]

It's actually introns that are taken out and exons that are left in.

*facepalm*

lol yeah, so true, a normal heidi-slipup when typing too late at night for her

[vox nihili]

*facepalm*

lol yeah, so true, a normal heidi-slipup when typing too late at night for her

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