Search results
Results from the WOW.Com Content Network
Ribosomes (/ ˈ r aɪ b ə z oʊ m,-s oʊ m /) are macromolecular machines, found within all cells, that perform biological protein synthesis (messenger RNA translation). Ribosomes link amino acids together in the order specified by the codons of messenger RNA molecules to form polypeptide chains.
The ribosome has two binding sites for tRNA. They are the aminoacyl site (abbreviated A), and the peptidyl site/ exit site (abbreviated P/E). Concerning the mRNA, the three sites are oriented 5' to 3' E-P-A, because ribosomes move toward the 3' end of mRNA. The A-site binds the incoming tRNA with the complementary codon on the mRNA.
Mature mRNA is then read by the ribosome, and the ribosome creates the protein utilizing amino acids carried by transfer RNA (tRNA). This process is known as translation. All of these processes form part of the central dogma of molecular biology, which describes the flow of genetic information in a biological system.
The eukaryotic cell cycle consists of four distinct phases: G 1 phase, S phase (synthesis), G 2 phase (collectively known as interphase) and M phase (mitosis and cytokinesis). M phase is itself composed of two tightly coupled processes: mitosis, in which the cell's nucleus divides, and cytokinesis, in which the cell's cytoplasm and cell membrane divides forming two daughter cells.
A ribosomal protein (r-protein or rProtein [1] [2] [3]) is any of the proteins that, in conjunction with rRNA, make up the ribosomal subunits involved in the cellular process of translation. E. coli, other bacteria and Archaea have a 30S small subunit and a 50S large subunit, whereas humans and yeasts have a 40S small subunit and a 60S large ...
[1] [2] Eukaryotic ribosomes are also known as 80S ribosomes, referring to their sedimentation coefficients in Svedberg units, because they sediment faster than the prokaryotic ribosomes. Eukaryotic ribosomes have two unequal subunits, designated small subunit (40S) and large subunit (60S) according to their sedimentation coefficients.
The G 1 phase, gap 1 phase, or growth 1 phase, is the first of four phases of the cell cycle that takes place in eukaryotic cell division. In this part of interphase , the cell synthesizes mRNA and proteins in preparation for subsequent steps leading to mitosis.
In eukaryotes, SRP binds to the signal sequence of a newly synthesized peptide as it emerges from the ribosome. [1] This binding leads to the slowing of protein synthesis known as "elongation arrest", a conserved function of SRP that facilitates the coupling of the protein translation and the protein translocation processes. [5]