Which ion is required for assembly of ribosomal subunits?

Magnesium ions are required for association of ribosomal subunits. In the absence of magnesium ions, the formation will not be preceded. Most of the ribosomal proteins are fall under the category of energy-consuming enzymes families.

Which is must for binding of subunits of ribosome?

Each ribosomal subunit has three binding sites for tRNA: designated the A (aminoacyl) site, which accepts the incoming aminoacylated tRNA; P (peptidyl) site, which holds the tRNA with the nascent peptide chain; and E (exit) site, which holds the deacylated tRNA before it leaves the ribosome.

Which is responsible for joining the subunits of proteins?

Ribosomes link amino acids together in the order specified by the codons of messenger RNA (mRNA) molecules to form polypeptide chains. Ribosomes consist of two major components: the small and large ribosomal subunits.

Which of the following ion on which concentration is required for the binding of ribosomal subunits?

Mg2+ and K+ are the prevalent di- and monovalent cations inside the cells in all three domains, playing a dominant role in structure and function of biological macromolecules. Ribosomes bind a substantial fraction of total Mg2+ and K+ cations.

Which of the following helps in synthesis of ribosomal subunits?

Eukaryote ribosomes are produced and assembled in the nucleolus. Ribosomal proteins enter the nucleolus and combine with the four rRNA strands to create the two ribosomal subunits (one small and one large) that will make up the completed ribosome (see Figure 1).

What is Ergosomes?

A polyribosome (or polysome or ergosome) is a group of ribosomes bound to an mRNA molecule like “beads” on a “thread”. It consists of a complex of an mRNA molecule and two or more ribosomes that act to translate mRNA instructions into polypeptides.

Why does the ribosome have two subunits?

Ribosomes contain two different subunits, both of which are required for translation. The small subunit (“40S” in eukaryotes) decodes the genetic message and the large subunit (“60S” in eukaryotes) catalyzes peptide bond formation.

What is the function of the small subunit of the ribosome?

The small ribosomal subunit programs protein synthesis; it binds mRNA and mediates the interaction between mRNA codons and tRNA anticodons. The large subunit takes care of production; it contains the peptidyl transferase site, the site at which peptide bonds are formed.

Why is the three dimensional shape of a protein so important?

The shape of a protein is critical to its function because it determines whether the protein can interact with other molecules.

What are the three bases found on mRNA?

Like DNA, RNA is made up of four bases. Three of these bases, adenine (A), cytosine (C), and guanine (G), are the same as DNA.

At what concentration of Mg 2+ ions the dimer of ribosomes is formed?

0.001 M
Each ribosome is made up of two subunits, a smaller subunit and another larger subunit. These two subunits are associated with the help of Mg2+ ions (at 0.001 M concentration).

What concentration is Mg2+?

“Mg2+ is the most abundant divalent cation in living cells. It is present at a total cellular concentration of 15–25 mM in both prokaryotic and mammalian cells (primary sources).”

What is the function of the magnesium ions in RNA polymerase?

Magnesium ions (Mg++) are thought to play two roles in the function of the RNA polymerase holoenzyme: 1) to promote the polymerization reaction to generate the RNA transcript and, 2) to bind and bend the DNA template. Where are these metal ions located on the RNA polymerase holoenzyme?

How are the 20 amino acids aligned on the mRNA template?

During translation, each of the 20 amino acids must be aligned with their corresponding codons on the mRNA template. All cells contain a variety of tRNAsthat serve as adaptors for this process. As might be expected, given their common function in protein synthesis, different tRNAs share similar overall structures.

Do mRNA transcripts contain both introns and exons?

The transcripts produced contain both exons and introns. a. A polycistronic mRNA may be transcribed if the gene products are used in the same pathway or needed at the same time. The closeup shows the secondary structure of the sigma (σ) subunit, which consists of four domains.

How is mRNA recognized and brought to the ribosome?

The mRNA is recognized and brought to the ribosome by the eIF-4 group of factors. The 5´ cap of the mRNA is recognized by eIF-4E. Another factor, eIF-4G, binds to both eIF-4E and to a protein (poly-A binding protein or PABP) associated with the poly-A tail at the 3’ end of the mRNA.