1. 1 pt) Given the chart below, calculate the pl for the following tripeptide: H
ID: 3516395 • Letter: 1
Question
1. 1 pt) Given the chart below, calculate the pl for the following tripeptide: His-Met-Cys. Input your answer rounded to the nearest tenth. (Hint: draw the tripeptide first, then determine the ionizable groups.) lonizable groups in Approximate pKa in 3.1 Side chain c 6.0 8.0 8.3 10.8 10.9 12.5 a-amino Thio E-amino Aromatic 2. (1 pt.) Answer the following questions in reference to the diagram below a) What structure is shown in the box in the diagram? Be specific. b) What type of bonds hold this type of structure together? 3. (1 pt.) Preproinsulin is an example of what level of protein structure? a) Primary b) Secondary c) Tertiary d) Quaternary 4. (1 pt.) In forming polypeptides, is water used or released? What is the name for this type of reactioni? SPELLING COUNTS! (Each answer should be a single word) S. (1 pt.) Which of the following statements about keratin is not correct? a) The disulfide bridges are formed between cysteine residues. b) The secondary structure of keratin is an extended a-helix. c) As a fibrous protein, keratin tends to be insoluble. d) Keratin's quaternary structure is held together primarily by hydrogen bonds.Explanation / Answer
1. Given peptide sequence = His-Met-Cys
MW = 1.07 kDa
pI = 5.03
2.
a. Antiparallel beta-sheet
c. Hydrogen bonds
3. Option C is correct.
Preproinsulin is a single peptide.
4. Yes.
Water is released when a peptide bond is formed. Hence these reactions are called CONDENSATION reactions.
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