Genetic information is transferred from DNA to protein;describe and discuss this process .?

Question

Describe and discuss this process with particular detailed reference to the key roles played by the different types of RNA.

Answer 1

you are lazy!!!
read you book!! I'm sure it's written there!!

Answer 2

PROTEIN SYNTHESIS

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 3

in simple terms, DNA is copied by RNA polymerase, this copy has useless parts cut out (introns), and the part left forms mRNA, the mrna leaves the nucleus, goes to rrna (ribosome), the ribosome hosts the mrna and trna carries amino acids over to the ribosome, matches up with the mrna, and forms a protein

Answer 4

Protein biosynthesis (Synthesis) is the process in which cells build proteins. The term is sometimes used to refer only to protein translation but more often it refers to a multi-step process, beginning with amino acid synthesis and transcription which are then used for translation. Protein biosynthesis, although very similar, differs between prokaryotes and eukaryotes.

[edit] Amino acid synthesis
Main article: Amino acid synthesis
Amino acids are the monomers which are polymerized to produce proteins. Amino acid synthesis is the set of biochemical processes (metabolic pathways) which build the amino acids from carbon sources like glucose. Not all amino acids may be synthesised by every organism, for example adult humans have to obtain 8 of the 20 amino acids from their diet.

The amino acids are then loaded onto tRNA molecules for use in the process of translation.


[edit] Transcription
Main article: Transcription (genetics)
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.

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.
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.
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, poly-A-polymerase adds a poly-A tail onto the 3’ end for stabilization, protection from cytoplasmic hydrolytic enzymes and as a template for further process. Also in eukaryotes (higher organisms) the vital process of splicing occurs at this stage by the spliceosome enzyme. It removes the introns (non-coding bits of genetic material) and glues together the exons (the segments that code for a specific protein).
The mRNA now exits the nuclear pore to be translated.

[edit] Translation
Main article: Translation (genetics)
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 is shown in the picture below.


The chemical process of connecting two amino acids resulting in a dipeptide and a water molecule
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.


[edit] Events following Protein Biosynthesis (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 5

use your book! (look for both tRNA and mRNA---theyre a big part of this process)