few NBDE questions, please help

[KKB]

I have 2 questions and would appreciate help on explanations. Thanks in advance.

1) What is the max number of amino acids that can be coded for a polyneucleotide which contains only ADENINE, URACIL and CYSTOCINE? and why

2) The following peptide carries which of the following charges in H2O at PH-7. ARG-LEU-PHE-LYS-GLU-GLY
a) 2 b) 1 c) 0 d) -1 e) -2 and why.

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[bombshell]

I have 2 questions and would appreciate help on explanations. Thanks in advance.

1) What is the max number of amino acids that can be coded for a polyneucleotide which contains only ADENINE, URACIL and CYSTOCINE? and why
3on step 3, that is 3*3*3=27 - 27 differnt combinations between the 3 bases to produce different codons for the different aminoacids

2) The following peptide carries which of the following charges in H2O at PH-7. ARG-LEU-PHE-LYS-GLU-GLY
a) 2 b) 1 c) 0 d) -1 e) -2 and why.

ARG is plus 1, so is glutamine, so in total charge of 2

 

[KKB]

Thanks a lot for the explanation. However the answer to 2nd question is B in crackthenbd sample exam. How would that be?

 

[dentistjpr]

In question2 only lysine has 1 positive charged at ph 7 in h2O all other amino acids below are neutral.

http://en.wikipedia.org/wiki/Amino_acid

scroll down and see the "Table of standard amino acid abbreviations and side chain properties"

Hope this helps.

 

[dentistjpr]

so yes the answer is 1 as given in crack the nbde.

 

[KKB]

Thanks, that explains the answer. Appreciate the help.

 

[ndbenbde1]

so yes the answer is 1 as given in crack the nbde.

Think that is not correct. ARG also have positive charge. and also LyS. But Glu has negative charge of -1. Hence the answer is 1+1-1 = 1

All other have 0.

Check the same wiki link for answer. Or I am missing something?

 

[dentistjpr]

Hey nbdenbde1 , you are right i think i read the 3 letter abbreviations wrong or something.....so yes
"ARG also have positive charge. and also LyS. But Glu has negative charge of -1. Hence the answer is 1+1-1 = 1" and the rest others are zero.

Sorry guys my mistake...