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CHAPTER 19 Problems
Learning Check
Solution
Nonpolar (NP)
Polar (P)
1) CH3 2) CH3
+ | |H3N—CH—COOH H2N—CH—COO–
Which structure represents: A. alanine at a pH above its pI?B. alanine at a pH below its pI?
Learning Check
1) CH3 2) CH3
+ | |H3N—CH—COOH H2N—CH—COO–
Which structure represents: A. alanine at a pH above its pI?B. alanine at a pH below its pI?
Solution
(2)(1)
Learning Check
Draw the condensed structural formula, and give the name and abbreviation for the dipeptide Ser-Thr.
OH CH3
| | CH2 O HCOH O + | ║ + | ║
H3N─CH─C─O– + H3N─CH─C─O– Ser Thr
Solution
OH CH3
| | CH2 O HCOH O + | ║ + | ║
H3N—CH—C—O– + H3N—CH—C─O– Ser peptide Thr
bond
OH CH3 | |
CH2 O H HCOH O + | ║ | | ║
NH3—CH—C─N—CH—C—O– + H2O
Seryl-Threonine (Ser-Thr)
Write the names and three-letter abbreviations of the tripeptides that could form from two glycines and one alanine.
Learning Check
Write the names and three-letter abbreviations of the tripeptides that could form from two glycines and one alanine.
Glycylglycylalanine Gly-Gly-Ala Glycylalanylglycine Gly-Ala-GlyAlanylglycylglycine Ala-Gly-Gly
Solution
Learning Check
What are the possible tripeptides formed from one each of leucine, glycine, and alanine?
Solution
What are the possible tripeptides formed from one each of leucine, glycine, and alanine?
Leu-Gly-AlaLeu-Ala-GlyAla-Leu-GlyAla-Gly-LeuGly-Ala-LeuGly-Leu-Ala
© 2013 Pearson Education, Inc. Chapter 19, Section 1 12
Learning Check
Write the name and three-letter abbreviation for thefollowing tetrapeptide.
H3N–CH– C–N–CH– C–N–CH–C–N–CH– CO–+
CH3 O H CH2 O H CH2 O H CH2 O
CH2CH–CH3
CH3
SH
S
CH3
© 2013 Pearson Education, Inc. Chapter 19, Section 1 13
Solution
Ala-Leu-Cys-MetAlanylleucylcysteylmethionine
Ala Leu Cys MetH3N–CH– C–N–CH– C–N–CH–C–N–CH– CO–+
CH3 O H CH2 O H CH2 O H CH2 O
CH2CH–CH3
CH3
SH
S
CH3
Indicate the type of protein structure as:1) primary 2) alpha helix3) beta-pleated sheet 4) triple helix
A. polypeptide chains held side by side by H bondsB. sequence of amino acids in a polypeptide chainC. corkscrew shape with H bonds between amino acidsD. three peptide chains woven like a rope
Learning Check
Indicate the type of protein structure as:1) primary 2) alpha helix3) beta-pleated sheet 4) triple helix
3 A. polypeptide chains held side by side by H bonds
1 B. sequence of amino acids in a polypeptide chain
2 C. corkscrew shape with H bonds between amino acids 4 D. three peptide chains woven like a rope
Solution
Select the type of tertiary interaction of the following. A. leucine and valineB. two cysteinesC. aspartic acid and lysineD. serine and threonine
1) disulfide 2) ionic3) H bonds 4) hydrophobic
Learning Check
Select the type of tertiary interaction of the following. 4 A. leucine and valine 1 B. two cysteines 2 C. aspartic acid and lysine 3 D. serine and threonine
1) disulfide 2) ionic3) H bonds 4) hydrophobic
Solution
Identify the level of protein structure of the following.A. beta-pleated sheetB. order of amino acids in a proteinC. a protein with two or more peptide chainsD. the shape of a globular proteinE. disulfide bonds between R groups
1) primary 2) secondary3) tertiary 4) quaternary
Learning Check
Identify the level of protein structure of the following. 2 A. beta-pleated sheet 1 B. order of amino acids in a protein 4 C. a protein with two or more peptide chains 3 D. the shape of a globular protein 3 E. disulfide bonds between R groups
1) primary 2) secondary3) tertiary 4) quaternary
Solution
What are the products of the complete hydrolysis of the tripeptide Ala-Ser-Val?
Learning Check
What are the products of the complete hydrolysis of the tripeptide Ala-Ser-Val?
The products are the three amino acids: alanine, serine, and valine.
Solution
Tannic acid is used to form a scab on a burn. An egg is hard-boiled by placing it in boiling water. What is similar about these two events?
Learning Check
Tannic acid is used to form a scab on a burn. An egg is hard-boiled by placing it in boiling water. What is similar about these two events?
Acid and heat cause the denaturation of protein. They both break bonds in the secondary and tertiary structures of proteins.
Solution