BSC 219 Lecture Notes - Lecture 9: Ribosome, Stem-Loop, 28S Ribosomal Rna

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21 Apr 2017

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Document Summary

Translation a codon is specific for one amino acid the mrna is read three ribonucleotides at a time. Different codons can code for the same amino acid mrna acts as an intermediate between the dna and the protein mrna is the template for translation three ribonucleotides make up a codon. Translation translation requires: 1) template mrna 2) ribosomes 3) trna. Ribosomes ribosome structure the ribosome is a large complex of rrna and proteins 40 nm dia(cid:373)ete(cid:396) co(cid:374)sists of (cid:1006) su(cid:271)u(cid:374)its o(cid:374)e (cid:862)la(cid:396)ge su(cid:271)u(cid:374)it(cid:863) o(cid:374)e (cid:862)s(cid:373)all su(cid:271)u(cid:374)it(cid:863) both (cid:373)ade of p(cid:396)otei(cid:374) a(cid:374)d (cid:396)rna. Ribosome structure ribosomes sizes were originally determined by sedimentation rate in a sucrose gradient svedberg units used for sedimentation rates s heaviest/largest lightest/smallest. Ribosome structure prokaryotic ribosomes prokaryotes have a ribosome that has a total size of 70s. The large subunit in prokaryotes is 50s 70s 50s 30s the small subunit in prokaryotes is 30s.

Related Questions

Facts about ribosomes

Indicate whether each of the following statements aboutribosomes is true or false.

1. Ribosomes are composed of tRNA and protein. TrueFalse
2. During translation in eukaryotes, some ribosomes remain free inthe cytoplasm while others attach to protein channels embedded inthe RER. TrueFalse
3. During initiation of translation, the small ribosomal subunitjoins to the mRNA and initiator rRNA, followed by the largeribosomal subunit. TrueFalse
4. When a ribosome first assembles on the mRNA, the initiator tRNAoccupies the A site while the P and E sites are empty.TrueFalse
5. During translation, a charged tRNA first binds to the ribosomeif its anticodon matches the codon in the E site. TrueFalse
6. A peptide bond forms between the amino acid attached to a tRNAin the A site and the growing polypeptide attached to a tRNA in theP site. TrueFalse
7. Uncharged tRNA molecules in the E site are ejected from theribosome. TrueFalse
8. No more than 2 tRNA molecules are bound to a ribosome at anygiven time. TrueFalse
9. During translocation of the ribosome, tRNA molecules move fromthe P site, to the A site, to the E site, and are then ejected fromthe ribosome. TrueFalse
10. During translation, an amino acid attached to a tRNA in the Asite is transferred to a growing polypeptide attached to a tRNA inthe P site. TrueFalse