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Ch.10 Proteins Workers of the Cell
Frost - General, Organic and Biological Chemistry 4th Edition
Frost4th EditionGeneral, Organic and Biological ChemistryISBN: 9780134988696Not the one you use?Change textbook
All textbooksFrost 4th EditionCh.10 Proteins Workers of the CellProblem 73c
Chapter 6, Problem 73c

For each of the following proteins, note whether the main secondary structure feature is α helix, β-pleated sheet, or both.
c. hemoglobin

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Understand the secondary structure of proteins: Proteins have secondary structures such as α helices and β-pleated sheets, which are stabilized by hydrogen bonding between the backbone atoms of the polypeptide chain.
Recall the structure of hemoglobin: Hemoglobin is a globular protein that functions as an oxygen carrier in the blood. It is composed of four polypeptide chains (two α chains and two β chains).
Identify the secondary structure of hemoglobin: Hemoglobin's polypeptide chains primarily consist of α helices as their main secondary structure feature.
Note the absence of β-pleated sheets: Hemoglobin does not have significant β-pleated sheet structures in its secondary structure.
Conclude that the main secondary structure feature of hemoglobin is the α helix.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Secondary Structure of Proteins

The secondary structure of proteins refers to the local folded structures that form within a polypeptide due to hydrogen bonding between backbone atoms. The two most common types are α helices, which are coiled structures, and β-pleated sheets, which are formed by parallel or antiparallel strands. Understanding these structures is crucial for analyzing protein function and stability.
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Hemoglobin Structure

Hemoglobin is a globular protein found in red blood cells, responsible for transporting oxygen. Its structure includes both α helices and β-pleated sheets, contributing to its functionality and stability. The presence of these secondary structures allows hemoglobin to undergo conformational changes necessary for oxygen binding and release.
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Protein Folding and Function

Protein folding is the process by which a polypeptide chain acquires its functional three-dimensional structure. The specific arrangement of secondary structures, such as α helices and β-pleated sheets, plays a critical role in determining the overall shape and function of the protein. Misfolding can lead to loss of function or diseases, highlighting the importance of understanding these structural features.
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Related Practice
Textbook Question

Indicate what type(s) of intermolecular forces are disrupted and what level of protein structure is changed by the following denaturing treatments:

c. egg whites whipped in a mixing bowl to make meringue

Textbook Question

Identify the level of protein structure associated with each of the following:

b. disulfide bridge

Textbook Question

Indicate what type(s) of intermolecular forces are disrupted and what level of protein structure is changed by the following denaturing treatments:

a. an egg placed in water at 100 °C and boiled for 10 minutes

Textbook Question

For each of the following proteins, note whether the main secondary structure feature is α helix, β-pleated sheet, or both.

a. collagen

Textbook Question

For each of the following proteins, note whether the main secondary structure feature is α helix, β-pleated sheet, or both.

e. hexokinase

Textbook Question

Identify the level of protein structure associated with each of the following:

d. salt bridges between polypeptides