How does the mRNA transcript find the ribosome?

The mRNA molecules are transported through the nuclear envelope into the cytoplasm, where they are translated by the rRNA of ribosomes (see translation). Messenger RNA (mRNA) then travels to the ribosomes in the cell cytoplasm, where protein synthesis occurs (Figure 3).

How does RNA find the ribosome?

Each ribosome contains at least one large rRNA and at least one small rRNA. In the nucleolus, the large and small rRNAs combine with ribosomal proteins to form the large and small subunits of the ribosome (e.g., 50S and 30S, respectively, in bacteria).

How does the ribosome know where to start translating the mRNA?

(1) Translation begins when a ribosome (gray) docks on a start codon (red) of an mRNA molecule in the cytoplasm. (2) Next, tRNA molecules attached to amino acids (spheres) dock at the corresponding triplet codon sequence on the mRNA molecule.

Why does mRNA bind with a ribosome?

Explanation: mRNA gets attached to the riosome, the site of protein synthesis. It helps in transferring amino acids in sequence as per the codon sequence in DNA for the synthesis of polypeptide chain.

How does the Escherichia coli RNA polymerase recognize a gene?

The DNA sequence to which RNA polymerase binds to initiate transcription of a gene is called the promoter. The DNA sequences involved in promoter function were first identified by comparisons of the nucleotide sequences of a series of different genes isolated from E. coli.

Where is the ribosome located?

Ribosomes are found ‘free’ in the cytoplasm or bound to the endoplasmic reticulum (ER) to form rough ER. In a mammalian cell there can be as many as 10 million ribosomes.

How is mRNA transcribed DNA?

During transcription, the DNA of a gene serves as a template for complementary base-pairing, and an enzyme called RNA polymerase II catalyzes the formation of a pre-mRNA molecule, which is then processed to form mature mRNA (Figure 1).

Where is mRNA translated?

ribosome
In translation, messenger RNA (mRNA) is decoded in a ribosome, outside the nucleus, to produce a specific amino acid chain, or polypeptide. The polypeptide later folds into an active protein and performs its functions in the cell.

How do mRNA help in the process of translation?

This process mainly involves the translocation of the ribosome on the mRNA, translating it with the help of tRNA that reads the mRNA and facilitates step by step addition of amino acids. …

What does the mRNA do in the process of translation?

The entire process is called gene expression. In translation, messenger RNA (mRNA) is decoded in a ribosome, outside the nucleus, to produce a specific amino acid chain, or polypeptide. The polypeptide later folds into an active protein and performs its functions in the cell.

How does RNA polymerase start transcription?

RNA polymerase attaches to the DNA molecule and moves along the DNA strand until it recognises a promoter sequence. These are known as the transcription start sites. The DNA double helix then unwinds and all the bases on each of the DNA strands are exposed.

What is the relationship between mRNA and ribosome?

Within the ribosome, the mRNA and aminoacyl-tRNA complexes are held together closely, which facilitates base-pairing. The rRNA catalyzes the attachment of each new amino acid to the growing chain. Interestingly, not all regions of an mRNA molecule correspond to particular amino acids.

What are the binding sites of the ribosome during translation?

When translation begins, the small subunit of the ribosome and an initiator tRNA molecule assemble on the mRNA transcript. The small subunit of the ribosome has three binding sites: an amino acid site (A), a polypeptide site (P), and an exit site (E).

How is information transferred from DNA to mRNA?

In the first step, the information in DNA is transferred to a messenger RNA ( mRNA) molecule by way of a process called transcription.