Concept explainers
(a)
Interpretation:
The more acidic peptide has to be identified. The explanation for the corresponding answer is to be stated.
Concept introduction:
The chemical compounds in which carbon is bonded with the acidic and basic group along with hydrocarbon side chain are known as amino acids. The amino acids are classified into acidic, basic, polar, non-polar, essential, and non-essential categories. The three-word abbreviation or one-word abbreviation is used for amino acids.
(b)
Interpretation:
The peptide that would emerge first from an anion-exchange column at
Concept introduction:
The chemical compounds in which carbon is bonded with the acidic and basic group along with hydrocarbon side chain are known as amino acids. The amino acids are classified into acidic, basic, polar, non-polar, essential, and non-essential categories. The three-word abbreviation or one-word abbreviation is used for amino acids.
(c)
Interpretation:
The
Concept introduction:
The term DNA stands for deoxyribonucleic acid. Deoxyribonucleic acid is the most important
(d)
Interpretation:
The structure of the aminoacyl-tRNA which would codes for the first amino acid in the biosynthesis of the peptide
Concept introduction:
The term DNA stands for deoxyribonucleic acid. Deoxyribonucleic acid is the most important biomolecule that stores genetic information of a living organism. In other words, DNA is the blueprint of all organisms. The DNA first synthesizes RNA by the process of transcription and then the RNA synthesizes the proteins by the process of translation.
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EBK ORGANIC CHEMISTRY STUDY GUIDE AND S
- 22-35 Why is histidine considered a basic amino acid when the pKa of its side chain is 6.0?arrow_forwardConsider the following peptide : Phe – Glu – Ser – Met and Val – Trp – Cys – Leu. Do these peptides have different net charges at (a) pH 1? (b) pH 7? Indicate the charges at both pH valuesarrow_forwardAn enzyme catalyzes the hydrolysis of an ester with a certain activity, but this activity is lost in a 3 M urea solution. What is the most likely explanation for the loss of activity? (A) Urea binds to the active site of the enzyme competitively with the substrate. (B) Urea causes the cleavage of the peptide bonds in the enzyme. (C) Urea causes the enzyme to denature and lose its specific three-dimensional shape. (D) Urea reacts with disulfide bonds in the enzyme.arrow_forward
- The amino acid cysteine has three ionizable groups with the indicated pKas values. Draw the shapes of the amino acid at each of the following pHs: (a) 12 (b) 1 (c) 8 (d) 3arrow_forward2. (a) Describe any two of the secondary structure elements found in peptides. (b) Why do Glycine and Proline destabilise an a-helix secondary structure element? (c) Provide a definition of the term isoelectric point? (d) Using the information given below, calculate the pl of the amino acid citrulline. H₂N pK₂ = 9.23 H₂N. NH COOH pK₂ = 2.27arrow_forwardAt very low pH, alanine is a diprotic acid that can be represented as H3N1-CH(CH3)-COOH. The pKa of the carboxyl group is 2.3, and the pKa of the UNH1 3 group is 9.7.(a) At pH 7, what fraction of the amino acid molecules dissolved in an aqueous solution will have the form H3N1-CH(CH3)-COO2?(b) What fraction of the molecules at this pH will havethe form H2N-CH(CH3)-COOH?arrow_forward
- Write the complete structures for the following peptides. Tell whether each peptide is acidic, basic, or neutral.(a) methionylthreonine (b) threonylmethioninearrow_forward(a) The isoelectric point (pI) of phenylalanine is pH 5.5. Draw the structure of the major form of phenylalanine at pHvalues of 1, 5.5, and 11.(b) The isoelectric point of histidine is pH 7.6. Draw the structures of the major forms of histidine at pH values of 1, 4,7.6, and 11. Explain why the nitrogen in the histidine ring is a weaker base than the a-amino group.(c) The isoelectric point of glutamic acid is pH 3.2. Draw the structures of the major forms of glutamic acid at pH valuesof 1, 3.2, 7, and 11. Explain why the side-chain carboxylic acid is a weaker acid than the acid group next to thea-carbon atomarrow_forwardWrite the complete structures for the following peptides. Tell whether each peptide is acidic, basic, or neutral.(a) methionylthreonine (b) threonylmethionine(c) arginylaspartyllysine (d) Glu-Cys-Glnarrow_forward
- What is the predominant form of each of the following amino acids at pH = 11? What is the overall charge on the amino acid? (a) valine; (b) proline; (c) glutamic acid; (d) lysinearrow_forwardGlycine is a diprotic acid, which can potentially undergo two dissociation reactions, one for the a-amino group (-NH3), and the other for the carboxyl (-COOH) group. Therefore, it has two pKą values. The carboxyl group has a pK₁ of 2.34 and the a-amino group has a pK₂ of 9.60. Glycine can exist in fully deprotonated (NH₂-CH₂-COO-), fully protonated (NH3-CH₂-COOH), or zwitterionic form (NH3-CH₂-COO-). Match the pH values with the corresponding form of glycine that would be present in the highest concentration in a solution of th pH. fully deprotonated form NH,−CH,−COO- pH 11.9 pH 6.0 pH 8.0 fully protonated form NH3-CH₂-COOH pH 1.0 Answer Bank pH 7.0 zwitterionic form NH3-CH₂-COO-arrow_forwardIdentify the following amino acid at pH = 7 (aqueous form): (COO-)–CH(NH3+)–CH2–(COO-) aspartic acid asparagine histidine arginine lysine Describe the amino acid illustrated above (at pH = 7.0). it is a non-polar, positively-charged amino acid it is a polar, positively-charged amino acid it is a polar, uncharged amino acid it is a polar, negatively-charged amino acid it is a non-polar, negatively-charged amino acid How many chiral carbons are present in the above amino acid (in aqueous form)? zero chiral carbons one chiral carbon two chiral carbons three chiral carbons four chiral carbons How many optical isomers (stereoisomers) are possible for the above amino acid (aqueous form)? 21 = 2 optical isomers 22 = 4 optical isomers 23 = 8 optical isomers 24 = 16 optical isomers 25 = 32 optical isomersarrow_forward
- Introduction to General, Organic and BiochemistryChemistryISBN:9781285869759Author:Frederick A. Bettelheim, William H. Brown, Mary K. Campbell, Shawn O. Farrell, Omar TorresPublisher:Cengage Learning