Can someone explain how protein synthesis works?

Question

Please do so, in easy understandable terms. THanks!

Answer 1

Protein synthesis is achieved through a combination of steps.

1) Transcription
2) Translation
3) protein folding and organisation

TRANSLATION - This is split into 3 processes:

1) Intiation - An enzyme (RNA polymerase) binds to the double helix of DNA and begins to split the strands in two. Now there are two separate strands. One acts as a template strand giving the correct code to work from and because it is no longer attached to the other strand it can be easily 'read'. Spare nucleotides in the surrounding solution begin to pair to the nucleotides on the template strand (in the correct pair i.e. Adenine with Thymine and Guanine with Cytosine).

2) Elongation - Spare nucleotides continue to add to the growing 'new' strand by the same method until the whole length of DNA has been 'read'

3) Temination - There are certain codes on the template strand that tell the new strand to stop growing.

You now have a new strand of nucleotides that correspond to the original DNA strand. This new strand is known as messengerRNA (mRNA).

All this occurs in the nucleus where the DNA is kept. The next step (translation) moves out of the nucleus and occurs in the cytoplasm of the cell.

2)TRANSLATION - Now you have a new strand of nucleotide bases (your mRNA). However proteins are not made of nucleotide subunits. Proteins are made of amino acid subunits. So translation is the process by which the nucleotide strand acts as a template to make a corresponding amino acid strand.

This is done with a new type of RNA called transferRNA (tRNA).
Each tRNA molecule is structured so that at one end there is a specific amino acid and at the other end theres the matching nucleotide code that specifies that amino acid.

As the new mRNA strand moves from the nucleus to the cytoplasm it comes into contact with the tRNA molecule. The mRNA strand begins to feed into the tRNA molecule and the tRNA molecule takes over the job of reading the mRNA and finding the correct corresponding amino acid. As it finds more and more the tRNA connects each amino acid together until a simple protein is formed.

HOW DOES THE tRNA 'READ' THE mRNA?
The mRNA molecule can be thought of as a paragraph from a book and every word in the book codes for an amino acid. Every 'word' is 3 letters long i.e. 3 nucleotides long and each 'word' is knwon as a 'codon'. So every 3 nucleotides i.e. every codon codes for a specific amino acid. The tRNA molecule is very clever and reads the mRNA just like an imaginary book before converting it into'amino acid' language.

3) PROTEIN FOLDING AND ORGANISATION
Once you have a single linear strand of amino acids the chain begins to fold and organise into the correct protein.

Obviously this is an extremely complex process and iv tried to word it as simply as possible but trust me it will just 'click' one day and you'll get it! Many many enzymes are involved in all these processes.

All can be evaluated by the central dogma of biology which describes how a gene creates a protein (follow the diagram from top to bottom):

DNA
(Transcription)
RNA
(Translation)
PROTEIN

I really hope this helps! By looking at appropriate diagrams i.e. of tRNA etc you will understand much better!

Answer 2

Three essential steps in protein synthesis: 1) Translation: DNA polymerase binds to the DNA strand when promoters previous to a gene are activated. It binds to a start codon on the anti-experience strand of DNA (so it will be TAC). It strikes along the DNA strand copying the DNA sequence in complementary RNA nucleotides. When it reaches a discontinue codon, it unbinds and releases a mRNA (messenger RNA) strand. This moves through the nucleolus (where the DNA is stored) into the nucleus the place it is spliced. That is where introns are reduce out of the mRNA molecule. Introns are non-coding sequences inside a gene. They're suggestion to shield against mutations. After splicing has occured, they transfer into the rER (hard endoplasmic reticulum). 2) Transcription: Eukaryotic ribosomes include two sub-units, a huge sub-unit and a small sub-unit. At the start, a mRNA molecule will bind to a small ribosomal sub-unit. Ribosomes have two sites which expose three nucleotides (a codon). The '' codon (AUG) initially allows binding to the ribosome. The uncovered AUG codon binds to a transfer RNA (tRNA) molecule. This tRNA molecule incorporates a methionine amino acid, when this binds to the 'begin' codon, it reasons the gigantic ribosomal sub-unit to glue additionally. The 2d tRNA molecule carrying the 2d amino acid coded for then binds to the mRNA molecule on the 2d website. This catalyses a condensation reaction with the initial methionine forming a peptide bond between the two amino acids (an OH group from the COOH finish and an H team for the NH2 finish are lost as water). This reaction also motives a conformational trade within the ribosome, which moves the mRNA alongside one codon, and factors the first tRNA to unbind. The following codon in the sequence is then equipped to bind to the following tRNA, and the following amino acid is delivered to the chain. This continues except a 'discontinue' codon is reached, this motives a 'stop' element to bind to the mRNA and ribosome. This reasons the ribosome (both sub-models) to unbind from the mRNA molecule and the amino-acid chain (now a polypeptide) to be launched. 3) modification When made with the aid of the ribosome, the polypeptide is effortlessly a protracted chain of amino acids, it will probably perform no targeted functions, as a way to participate in tricky tasks, it need to fold. The rER contains many motives which aid the protein to fold in an awfully unique approach, one of the crucial protein fold spontaneously as a result of cost imbalances between amino acids (for illustration α-helices and β-pleated sheets kind spontaneouly). As soon as folded, the protein is both excreted with the aid of the cell, used inside the telephone or modified additional. Additional amendment occurs within the Golgi equipment. Enzymes and chemical compounds inside vesicles within the Golgi apparatus, reduce detailed amino acids off the protein, add amino acids on, add sugars, lipids or inorganic businesses.

Answer 3

Visit this link, a video of Protein Synthesis http://www.biostudio.com/demo_freeman_protein_synthesis.htm
If that is hard to understand, here's another visual:
http://www.lewport.wnyric.org/jwanamaker/animations/Protein%20Synthesis%20-%20long.html

Answer 4

i will attempt to describe it as quickly as i'm able to... DNA is replicated > DNA is transcribed into mRNA > mRNA enters cytoplasm > great and small subunit of ribosome embody mRNA > tRNA provides the correosponding Amino Acid via correosponding the mRNA codon's with its anti-codon > this creates a polypeptide and lengthens it > ultimately a quit code would be reached > protein will undergo further exchange via 4 categories of platforms and that they are: accepted platforms, secondary platforms, tertiary platforms and quaterny platforms.

Answer 5

this site explains it really well, a lot better than I could, at least.

http://www.lewport.wnyric.org/jwanamaker/animations/Protein%20Synthesis%20-%20long.html

Answer 6

http://www.accessexcellence.org/RC/VL/GG/protein_synthesis.html
http://www.wisc-online.com/objects/index_tj.asp?objid=AP1302

These two sites are really good
hope it will help