17. Which of the following is true about the sorting pathway...

17. Which of the following is true about the sorting pathway for proteins destined for incorporation into lysosomes or the plasma membrane of eukaryotic cells? A. Binding of SRP to the signal peptide and the ribosome temporarily accelerates protein synthesis. B. The newly synthesized polypeptides include a signal sequence at their carboxyl termini. C. The signal peptide is cleaved off inside the mitochondria by signal peptidase. D. The SRP binds to the signal sequence soon after it appears outside the ribosome. E. The signal sequence is added to the polypeptide in a post-translational modification reaction. 18. In bacteria the elongation stage of translation does NOT involve: A. aminoacyl-tRNAs. B. EF-Tu. C. GTP. D. IF-2. E. peptidyl transferase. 19. An example of a steroid hormone is: A. epinephrine. B. retinoic acid. C. testosterone. D. thromboxane. E. thyroxine. 20. Formation of the ribosomal initiation complex for bacterial protein synthesis does NOT require: A. EF-Tu. B. tRNA attached to methionine. C. GTP. D. initiation factor 2 (IF-2). E. mRNA.

Transcript

00:02 Which of the following statement is true about the sorting pathway for proteins that are destined for lysosomes or plasma membrane? so proteins pathway for lysosomes or plasma membrane.

00:21 So whenever a new polypeptide is synthesized, it is been added with a signal peptide and srp protein.

00:28 So let's see the statements that are been true.

00:31 First is srp, srp signal recognition protein.

00:36 It's added to the signal peptide and ribosome which temporarily accelerate the protein synthesis.

00:43 This is a wrong statement because when the srp is added to the ribosome at that time temporarily the protein synthesis would be halted.

00:53 So this is a wrong statement.

00:56 A newly synthesized polypeptide will be added by this signal sequence to its c2.

01:01 Terminal this is also wrong because to the end terminus it is been added third is signal peptide is been cleaved off in the mitochondria by signal peptides this is wrong because this is done in endoplasmic reticulum fourth is signal peptide is added to the srp when srp is added to a signal peptide when the is added to the season peptide on the protein when it protein or polypeptide you could say that it emerges out of the chromo rhizome this is true.

01:33 So when a polypeptide, that is, translation is going on, polypeptide synthesis is going on, when it emerges out to its end terminal, signal peptide is been added and srp is also been added which guides.

01:50 This will simply guide the newly synthesized polypeptide.

01:56 So this is a correct statement that when the ribosome is going to exit out the next.

02:03 Newly synthesized polypeptide means at the starting point only when the polypeptide is still being synthesized so whenever it comes out of the ribosome immediately signal peptide and srp will be added and last is that signal peptide is been removed of during post -translation modification sorry signal peptide is added during post -translation modification so this is wrong signal peptide is not added during post -translation modification.

02:34 It is added during the translation.

02:36 So this statement is again wrong.

02:40 Correct statement for this question is option d.

02:44 Okay, moving further, in bacteria, elongation process of translation will not involve what? first, amino acid rnas.

02:55 Of course, we need amino acid rna for the translation process.

03:00 So you cannot ignore this...