Are the following molecules α-amino acids? Why?

Why is the solubility of proteins in water lower at their isoelectronic points?

Which of the following statements best describes the difference between complete and incomplete proteins?

Which of the following amino acids are correctly represented by the given three-letter abbreviations?

I. Cys — cysteine

II. Asn — aspartic acid

III. Arg — arginine

IV. Pro — serine

V. Glu — glutamine

Which amino acid is represented by the code 'Phe'? Draw its structure.

Which amino acid is represented by the letter C? Draw its structure ignoring stereochemistry.

Which of the amino acids below is most likely to be found on the exterior of a water-soluble protein, and which of them is more likely to be found on the interior?

i. tryptophan 

ii. threonine 

iii. lysine 

iv. glutamic acid

Consider the pairs of amino acids below:

A. alanine and valine

B. leucine and isoleucine

C. glycine and phenylalanine

D. serine and threonine

i. Which pair have side chains capable of hydrogen bonding?

ii. Draw each structure hydrogen bonding to one another.

iii. Sketch each structure hydrogen bonding to water.

Provide the one-letter and three-letter abbreviations for amino acids glutamate and serine, and specify the functional group present in each of their side chains.

Which of the following dipeptides and tripeptides are correctly paired with their corresponding 1-letter abbreviations?

I. Arg-Ser: R-S

II. Glu-Asn-Gly: Q-N-G

III. Pro-Asp-Tyr: P-D-Y

IV. Met-Lys: M-L

V. Leu-Cys-Val: L-C-V

i. Provide the line-angle structure for valylglycylserine.

ii. Give its three-letter abbreviation.

iii. Give its one-letter abbreviation.

(Ignore stereochemistry)

Label the N-terminus and C-terminus in the structures of the following peptides.

Identify the planar units present in the following generic protein chain.