BIOTECHNOLOGY Lecture Notes - Lecture 2: Ribosome-Binding Site, Prokaryotic Translation, Eukaryotic Translation

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learnthebasics07

20 Dec 2022

School

Guru Nanak Dev University

Department

Biology

Course

BIOTECHNOLOGY

Professor

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Document Summary

The shine-dalgarno sequence is a ribosomal binding site in the mrna, generally located 8 bases upstream of the start codon aug. The shine-dalgarno sequence exists both in bacteria and archaebacteria. The six-base consensus sequence is aggagg; in e. coli, for example, the sequence is aggaggu. This sequence helps recruit the ribosome to the mrna to initiate protein synthesis by aligning it with the start codon. The assembly of the ribosome on an mrna occurs one subunit at a time. The small subunit associates with the mrna first mediated by base-pairing interactions between the ribosomal binding sites and the 16s rrna. The small subunit is positioned on the mrna such that the start codon aug will be in the p-site when the large subunit joins the complex. Each prokaryotic ribosome, shown schematically, has three binding sites for trnas. Met is used for the initiation codon and is called the initiator trna whereas trnam.

Related Questions

Match the following:

1	Region which lies upstream of thetranslation start site contains the Shine Dalgarno sequence
2	Sequence added to the 3' end of thepre-mRNA which affects mRNA stability
3	Establishes the reading frame andspecifies the first amino acid of the protein chain
4	DNA sequence that the transcriptionapparatus recognizes and binds to initiate transcription
5	Expressed sequences of DNA that arenot removed during alternative splicing
6	Signals the end of translation andthe protein molecule
7	Group of three nucleotides that codefor an amino acid
8	Site begins the coding region of thegene and is located 25-30 nucleotides downstream of the TATAbox
9	Non-coding sequences of DNA thatintervene within coding regions of a gene
	10 Ribosome binding site ineukaryotes; functions in the initiation of translation and mRNAstability
11	A sequence which lies downstream ofthe coding region of the gene; determines the location of the 3'cleavage site in the pre-mRNA molecule
12	Sequence of nucleotides at the 3' endof the mRNA that is not translated into protein; affects thetranslation and stability of the mRNA molecule

A.	5' untranslated region
B.	AAUAAA consensus sequence
C.	Promoter
D.	Transcription start site
E.	3' untranslated region
F.	Introns
G.	Initiation codon (AUG)
H.	Poly(A) tail
I.	5' cap
J.	Termination codon (UAA, UGA, UAG)
K.	Exons
L.	Sense codon

ivorymacaw91

Please please please I reallly need help with the following 5 questions.

Question 1

Which of the following is responsible for directing the prokaryotic ribosome to the +1 start site:

	a.	the 3' UTR
	b.	the AUG codon
	c.	Kozak sequence
	d.	Okasaki fragment
	e.	Shine Dalgarno sequence

Question 2

In translation, mRNAs are READ in the:

	a.	5' to 3' direction and polypeptide chains are synthesized amino to the carboxyl ends
	b.	5' to 3' direction and polypeptide chains are synthesized carboxyl to the amino ends
	c.	3' to 5' direction and polypeptide chains are synthesized carboxyl to the amino ends
	d.	3' to 5' direction and polypeptide chains are synthesized amino to the carboxyl ends

Question 3

Which of the following terms describes a tRNA to which an amino acid has been added:

	a.	charged tRNA
	b.	activated tRNA
	c.	stimulated tRNA
	d.	hydrolyzed tRNA

Question 4

The ability of some tRNA to recognize more than one codon in mRNA is explained by which of the following:

	a.	a reading frameshift
	b.	a reading mistake
	c.	Redundancy Theory
	d.	Wobble Hypothesis

Question 5

One essential component in eukaryotic mRNAs recognized by translation initiation factors is the

	a.	TATA box
	b.	AUG initiation codon
	c.	7-methylguanosine cap
	d.	Shine-Dalgarno sequence

blackporcupine6

1. What is the Shine-Dalgarno sequence? What binds to the sequence during translation? Describe some of the ways in which the sequence can vary, addressing the consequences that any such variation has on translation efficiency. In Detail

2. Describe the A, P, and E sites of the ribosome. Where are they located? What occupies each of the sites during the following stages of translation:

a. upon creation of the 70s initiation complex

b. after an initial round of peptidyl transfer, prior to aminoacyl tRNA binding

c. following aminoacyl tRNA binding, but before the peptidyl transfer reaction

d. after peptidyl transfer, but before translocation is completed by EF-G

e. in the presence of puromycin, prior to peptidyl transfer

f. upon reaching a stop codon

g. following release of the polypeptide chain, but before the appearance of RRF

silverwhale182

BIOTECHNOLOGY Lecture Notes - Lecture 2: Ribosome-Binding Site, Prokaryotic Translation, Eukaryotic Translation

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