Could somebody describe protein synthesis because i don't get it?

Question

thanx everyone

Answer 1

Definition: process whereby DNA encodes for the production of amino acids and proteins.

This process can be divided into two parts:

1. Transcription

Before the synthesis of a protein begins, the corresponding RNA molecule is produced by RNA transcription. One strand of the DNA double helix is used as a template by the RNA polymerase to synthesize a messenger RNA (mRNA). This mRNA migrates from the nucleus to the cytoplasm. During this step, mRNA goes through different types of maturation including one called splicing when the non-coding sequences are eliminated. The coding mRNA sequence can be described as a unit of three nucleotides called a codon.

2. Translation

The ribosome binds to the mRNA at the start codon (AUG) that is recognized only by the initiator tRNA. The ribosome proceeds to the elongation phase of protein synthesis. During this stage, complexes, composed of an amino acid linked to tRNA, sequentially bind to the appropriate codon in mRNA by forming complementary base pairs with the tRNA anticodon. The ribosome moves from codon to codon along the mRNA. Amino acids are added one by one, translated into polypeptidic sequences dictated by DNA and represented by mRNA. At the end, a release factor binds to the stop codon, terminating translation and releasing the complete polypeptide from the ribosome.

Answer 2

So you have your DNA and as you know, DNA contains the genetic information to make your protein.

DNA is a double helix structure, to begin the protein synthesis, you need to separate the two helix.  The RNA polymerase will then 'sit' in to one of the strand and begin to work its way down the DNA to make RNA molecule.  This is what we call the RNA transcription.  Basically, you make RNA out of DNA.

The RNA that you have now is called the mRNA (messenger RNA).  mRNA is transferred from the nucleus to the cytoplasm.  mRNA undergoes changes, non-coding sites (introns) are removed and coding sites (exons) are joined together.  In bacteria, you don't have this kind of system as the RNA of bacteria contains no introns.  After this process, which is known as RNA splicing, you have a mature RNA.

A 'mature RNA' consists of a series of codon.  A codon consists of 3 nucleotides.  An amino acid is represented by a 3 nucleotides.  For instance, Alanine is represented by GCU.

The next step is translation, basically this is the step when you are making the protein.  The mature RNA should consists of a start codon (AUG), on which the ribosome starts reading.  The ribosome is capable of recognising the RNA via the tRNA... each tRNA consists of an amino acid.  So basically you have tRNA for Leucine, tRNA for Alanine, etc.

So one by one, the RNA is being translated via the tRNA anticodon... until you reach the 'end', which is a stop codon (UAG, UGA, UAA).

Hope it is clearer.  IM me if you need further help.

Answer 3

Protein synthesis:

Process whereby DNA encodes for the production of amino acids and proteins.

This process can be divided into two parts:

1. Transcription

Before the synthesis of a protein begins, the corresponding RNA molecule is produced by RNA transcription. One strand of the DNA double helix is used as a template by the RNA polymerase to synthesize a messenger RNA (mRNA). This mRNA migrates from the nucleus to the cytoplasm. During this step, mRNA goes through different types of maturation including one called splicing when the non-coding sequences are eliminated. The coding mRNA sequence can be described as a unit of three nucleotides called a codon.

2. Translation

The ribosome binds to the mRNA at the start codon (AUG) that is recognized only by the initiator tRNA. The ribosome proceeds to the elongation phase of protein synthesis. During this stage, complexes, composed of an amino acid linked to tRNA, sequentially bind to the appropriate codon in mRNA by forming complementary base pairs with the tRNA anticodon. The ribosome moves from codon to codon along the mRNA. Amino acids are added one by one, translated into polypeptidic sequences dictated by DNA and represented by mRNA. At the end, a release factor binds to the stop codon, terminating translation and releasing the complete polypeptide from the ribosome.

One specific amino acid can correspond to more than one codon. The genetic code is said to be degenerate.



You can go through this site for animation of protein synthesis,

Hope this could help you much better to understand.

Answer 4

Heres an interactive video. You move the mouse on an object as the video is playing and you get information.

http://www.asterpix.com/console/?avi=769...

http://www.youtube.com/watch?v=NJxobgkPE...

http://en.wikipedia.org/wiki/Protein_bio...

Answer 5

Protein synthesis consists of transription and translation.

Transcription-

One strand of the DNA double helix is used as a template by the RNA polymerase to synthesize a messenger RNA (mRNA). This mRNA moves from the nucleus to the cytoplasm. During this step, mRNA goes through whats called "splicing" when the non-coding sequences are eliminated (introns are removed and only extrons exit the cell). The coding mRNA sequence can be described as a unit of three nucleotides called a codon.

Translation-

The ribosome binds to the mRNA at the start codon (AUG) that is recognized only by the initiator tRNA. The ribosome proceeds to the elongation phase of protein synthesis. During this stage, complexes, composed of an amino acid linked to tRNA, also bind to the appropriate codon in mRNA by forming complementary base pairs with the tRNA anticodon. The ribosome moves from codon to codon along the mRNA. Amino acids are added one by one, translated into polypeptidic sequences dictated by DNA and represented by mRNA. At the end, a release factor binds to the stop codon, ending translation and releasing the complete polypeptide from the ribosome.

Hopefully that helps, it is a hard concept at first