Biochemistry : Identifying Specific Protein Structures

Study concepts, example questions & explanations for Biochemistry

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Example Questions

Example Question #65 : Identification By Structure

Primary protein structure is primarily held together by what type of bond?

Possible Answers:

Hydrogen bond

Phosphodiester bond

Ionic bond

Peptide bond

Van der waals interactions

Correct answer:

Peptide bond

Explanation:

Primary protein structures are composed of amino acids linked together by peptide bonds.  Secondary protein structures are held together by hydrogen bonds.  Phosphodiester bonds can be found between sugar and phosphate groups in the backbone of DNA.

Example Question #31 : Identifying Specific Protein Structures

Why is the tertiary structure of a protein always conserved, even more so than the primary structure?

Possible Answers:

Tertiary structure is more closely associated with the sequence of the protein

The primary and tertiary structure of a protein are equally conserved

The primary structure is more conserved than the tertiary structure

The bonds holding the tertiary structure are stronger than those of the primary structure

Tertiary structure is more closely associated with the protein's function

Correct answer:

Tertiary structure is more closely associated with the protein's function

Explanation:

The primary structure of a protein deals with its sequence while the tertiary structure deals with the folding of the protein. The folding of the protein is what determines its function, and because this is important in maintaining the life of organisms, the tertiary structure must be heavily conserved.

Example Question #67 : Identification By Structure

Which of these are negatively charged amino acids at pH 7?

I. Aspartic acid

II. Glutamic acid

III. Lysine 

IV. Arginine

Possible Answers:

I, II, and III

IV only

I and II

III and IV

I, III, and IV

Correct answer:

I and II

Explanation:

Amino acids are classified based on their charged (polar groups) at neutral pH (pH=7).Lysine (Lys, K), arginine (Arg, R) and histidine (His, H) are positively charged at neutral ph (pH=7), while aspartate and glutamate are negatively charged.

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