BIOL 2030 Lecture Notes - Lecture 6: Methionine, Hydrophile, Cholesterol

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greenpig633

25 Jun 2015

School

University of Virginia

Department

Biology

Course

BIOL 2030

Professor

Kittlesen

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Document Summary

In translation, the ribosomes read the rna from 5" to 3": protein synthesis occurs from neither 3" to 5" nor 5" to 3", made from amino acids amino acids don"t have 5" to 3", from amino to carboxyl, multiple trnas for one amino acid, if one trna had different amino acids (cid:224) the codon could have different amino acids (cid:224) the genetic code would be ambiguous, aminoacyl trna synthetase will always couple the right amino acid to the right trna(cid:224) these are the one that are responsible for the genetic code, 20 aminoacyl trna synthetase and 20 amino acids, aug codon (methionine) is the start codon **** remember this codon. Tail: hydrophobic, nonpolar (cid:224) no hydrogen bonds with water, two fatty acid chains bond with glycerol, shape of the structure: determined by bulkiness of the head in relation to the tail.

Related Questions

22. There are 20 amino acids and 64 possible codons. Which of the following is closer to the actual number of different tRNA molecules in a cell?

A. 4

B. 16

C. 20

D. 61

E. 64

23. There are 20 amino acids and 64 possible codons. How many different eukaryotic aminoacyltRNA synthetases are there? A. 1

B. 16

C. 20

D. 61

E. 64

24. Which way are the amino acid and tRNA attached in a charged tRNA?

A. Amino acid-5'tRNA3'-AMP B

. Amino acid-AMP-3'tRNA

C. AMP-amino acid-3'tRNA

D. Amino acid-3'tRNA5'-AMP

E. Amino acid-AMP-5'tRNA

25. The anticodon that recognizes the initiation codon in translation is

A. 5' AUG 3'

B. 3' AUG 5'

C. 5' ACU 3'

D. 5' UAC 3'

E. 3' UAC 5'

26. The first amino acid incorporated into a growing polypeptide

A. In bacteria is methionine and it is also methionine in eukaryotes

B. In bacteria is tryptophan, while it is methionine in eukaryotes

C. In bacteria is N-formyl methionine, while it is methionine in eukaryotes

D. In bacteria is N-formyl methionine and it is also N-formyl methionine in eukaryotes

E. In bacteria is methionine, while it is N-formyl methionine in eukaryotes

27. In E. coli the IF3 forces tRNAf Met to bind with

A. The A site of the ribosome

B. The P site of the ribosome

C. The E site of the ribosome

D. IF1

E. IF2

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

I just came across this abstract:

Aminoacyl-tRNA synthetases (aaRSs) are responsible for creatingthe pool of correctly charged aminoacyl-tRNAs that are necessaryfor the translation of genetic information (mRNA) by the ribosome.Each aaRS belongs to either one of only two classes with twodifferent mechanisms of aminoacylation, making use of either the29OH (Class I) or the 39OH (Class II) of the terminal A76 of thetRNA and approaching the tRNA either from the minor groove (29OH)or the major groove (39OH). Here, an asymmetric pattern typical ofdifferentiation is uncovered in the partition of the codonrepertoire, as defined by the mechanism of aminoacylation of eachcorresponding tRNA. This pattern can be reproduced in a uniquecascade of successive binary decisions that progressively reducescodon ambiguity. The deduced order of differentiation is manifestlydriven by the reduction of translation errors. A simple rule can bedefined, decoding each codon sequence in its binary class, therebyproviding both the code and the key to decode it. Assuming that thepartition into two mechanisms of tRNA aminoacylation is a relicthat dates back to the invention of the genetic code in the RNAWorld, a model for the assignment of amino acids in the codon tablecan be derived. The model implies that the stop codon was alwaysthere, as the codon whose tRNA cannot be charged with any aminoacid, and makes the prediction of an ultimate differentiation step,which is found to correspond to the codon assignment of the 22ndamino acid pyrrolysine in archaebacteria.

Granted, this is a few years old, but I often find myself havingto admit that "I don't know" when at the root of discussions onevolution. That is, once abiogenesis has occurred, we can go on andexplain the rich diversity of life, but sadly we really don't knowmuch before that critical step. Generally, those satisfied with"magic" as an answer posit their myths and fables, whereas I'drather try to actually find out what happened. Sadly, as theabstract shows, you actually need a level of education tounderstand papers such as this that is generally well beyond thosewho would deny the reality of evolution.

Does anyone have a collection of papers on abiogenesis that aremore accessible and understandable to laypeople?

BIOL 2030 Lecture Notes - Lecture 6: Methionine, Hydrophile, Cholesterol

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