Explain the process of protein synthesis in eucaryotic cells.?

Question

Please giving account to both transcription and translation.

Answer 1

TRANSCRIPTION

Transcription is the process by which an mRNA template, carrying the sequence of the protein, is produced for the translation step from the genome. Transcription makes the template from one strand of the DNA double helix, called the template strand. Transcription takes place in 3 stages.

1. Transcription starts with the process of initiation. RNA polymerase, the enzyme which produces RNA from a DNA template, binds to a specific region on DNA that designates the starting point of transcription. This binding region is called the promoter. As the RNA polymerase binds on to the promoter, the DNA strands are beginning to unwind.

2. The second process is elongation. RNA polymerase travels along the template (noncoding) strand, synthesizing a ribonucleotide polymer. RNA polymerase does not use the coding strand as a template because a copy of any strand produces a base sequence complementary to the strand which is being copied. Therefore DNA from the noncoding strand is used as a template to copy the coding strand.

3. The third stage is termination. As the polymerase reaches the termination stage, modifications are required for the newly transcribed mRNA to be able to travel to the other parts of the cell, including cytoplasm and endoplasmic reticulum for translation. A 5' cap is added to the mRNA to protect it from degradation. In eukaryotes a poly-A tail is added on the 3’ end for protection and as a template for further process. Also in eukaryotes (higher organisms) the vital process of splicing occurs at this stage.

TRANSLATION

During translation, mRNA previously transcribed from DNA is decoded by specialized cellular structures called ribosomes to make proteins. Protein biosynthesis is divided into initiation, elongation and termination phases.

The ribosome has sites, which allow another specialized RNA molecule, known as tRNA, to bind to the mRNA. Binding of the correct tRNA to the mRNA on the ribosome is accomplished by an "anticodon" that is part of the tRNA. Thus, the correct tRNA, chemically linked to a specific amino acid, is directed to the ribosome to be added to a growing (nascent) polypeptide. The chemical process of connecting two amino acids.

As the ribosome travels down the mRNA one codon at a time, another tRNA is attached to the mRNA at one of the ribosome sites. The first tRNA is released, but the amino acid that is attached to the first tRNA is now moved to the second tRNA, and binds to its amino acid. This translocation continues on, and a long chain of amino acid (protein), is formed.

When the entire unit reaches the stop codon on the mRNA, it falls apart and a newly formed protein is released. This is termination. It is important to know that during this process, many enzymes are used to either assist or facilitate the whole procedure.

EVENTS FOLLOWING PROTEIN SYNTHESIS

The events following biosynthesis include post-translational modification and protein folding. During and after synthesis, polypeptide chains often fold to assume, so called, native secondary and tertiary structures. This is known as protein folding.

Many proteins undergo post-translational modification. This may include the formation of disulfide bridges or attachment of any of a number of biochemical functional groups, such as acetate, phosphate, various lipids and carbohydrates. Enzymes may also remove one or more amino acids from the leading (amino) end of the polypeptide chain, leaving a protein consisting of two polypeptide chains connected by disulfide bonds.

Answer 2

Protein synthesis is a 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, which means that an aminoacid can be coded for by more than one codon.

This is a "visual" representation of the whole process:
http://youtube.com/watch?v=u9dhO0iCLww

Answer 3

I think you have to approach it from three perspectives; college education and its availability and affordability, retirement and what the future holds for them and how bad it could be as opposed to now and the way it is for their parents living on fixed incomes or about to live on fixed incomes, thirdly-the environment. While these things are not directly related all three hold huge social and financial impact for the younger adults of this country that will affect them for many years to come after they are well past their mid 30s and 40s an into their retirment years even. By becoming involved and helping and taking a hand now with the decisions and policies that will be made they are helping to set the course for THEIR future.

Answer 4

DNA undergo transcription and RNA is resulted. RNA is translated into proteins. the process of systhesis of protein from rna is called as translation and it involves 4 steps
- transfer of aminoacids to trna:- in this process the atp energy is involved and form aminoadenylatedcomplex by binding with aminoacids. then this complex binds to trna and the energy is eliminated by the formation of aminoacyl trna which intiate the synthesis of proteins
-intiation:-IF1,IF2,IF3 are the intiation factors involved in intiation
IF1,IF3 binds to mrna and IF2 binds to GTP. this complex binds the 30s ribosome and aminoacyltrna.
after the elimination of IF3 50s ribosome binds to the complex
-elongation:- EF-TU,EF-TS,GTP are involved in this step for transfering the charged trna(amino acyl trna) to A site. only the intiator trna binds at P site and the all other binds at A site then shifts to p site
-termination:- it is by termination codons uaa,uae,uea.
these are recognised by RF1,RF2,RF3 releasing factors
termination brings an end to translation

Answer 5

I'm not going to try and explain it all, since it would take about an hour for me to type it all out - but I'm going to send you to a link that explains it all very well. It includes transcription and translation.

Answer 6

dna is translated to RNA in the nucleus, the RNA exit the nucleous and reach the ribosomes, there using the RNA as a template protein are synthetized using aminoacids.

All the process involve hundreds on enzimes to cut and slice the RNA, and to assemble the proteins.

Answer 7

puchase medical enclyopedia book from doctor's syllabus.

Answer 8

could you repeat the question