Podcast Beta
Questions and Answers
What characteristic prevents free rotation around the bond between the carbonyl carbon and the nitrogen of the peptide bond?
Which condition is required to non-enzymatically hydrolyze peptide bonds?
What term is used to describe each component amino acid in a polypeptide?
What stabilizes an α-helix structure by extensive hydrogen bonding between the peptide-bond carbonyl oxygens and amide hydrogens?
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What type of secondary structure forms when two or more separate polypeptide chains are arranged in parallel or antiparallel to each other?
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What is the name of the linear sequence of linked amino acids in a protein?
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Why is understanding the primary structure of proteins important?
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What type of bond joins amino acids together in proteins?
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What results from the linkage of many amino acids through peptide bonds?
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What type of bond joins amino acids together in proteins?
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What is the name of the level of protein structure that involves the sequence of amino acids in a protein?
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What is the convention for naming the ends of a peptide chain?
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What condition results in proteins with abnormal amino acid sequences, causing improper folding and loss of normal function?
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What characteristic prevents free rotation around the bond between the carbonyl carbon and the nitrogen of the peptide bond?
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What is the convention for writing the free amino end (N-terminal) and the free carboxyl end (C-terminal) of a peptide chain?
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Which type of structure forms when two or more separate polypeptide chains are arranged in parallel or antiparallel to each other?
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What term is used to describe the portion of the amino acid remaining after the atoms of water are lost in the formation of the peptide bond?
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What is required to non-enzymatically hydrolyze peptide bonds?
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What type of bond has a partial double-bond character and is shorter than a single bond?
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Which structure is stabilized by extensive hydrogen bonding between the peptide-bond carbonyl oxygens and amide hydrogens?
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What is the term for the spiral structure consisting of a tightly packed, coiled polypeptide backbone core, with the side chains of the component amino acids extending outward?
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How many amino acids are contained in each turn of an α-helix?
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What type of secondary structure is formed by two or more separate polypeptide chains that are arranged in parallel or antiparallel to each other?
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What type of sheet appears 'pleated' due to the almost fully extended segments of polypeptide chains involved in hydrogen bonding?
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What characteristic prevents free rotation around the bond between the α-carbons in the polypeptide chain?
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What type of bond helps reverse the direction of a polypeptide chain, aiding in the formation of a compact, globular structure?
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Study Notes
Peptide Bonds and Structure
- Partial Double-Bond Character: The peptide bond exhibits a partial double-bond character due to resonance, preventing free rotation around the bond between the carbonyl carbon and nitrogen.
- Hydrolysis Conditions: Non-enzymatic hydrolysis of peptide bonds requires strong acids or bases and elevated temperatures.
- Amino Acid Component: Each amino acid in a polypeptide is referred to as a residue.
- Stabilization of Alpha Helix: The α-helix structure is stabilized by extensive hydrogen bonding between the carbonyl oxygens of one peptide bond and the amide hydrogens of another, four residues away.
- Secondary Structure Formation: Secondary structures, such as β-sheets, form when two or more polypeptide chains arrange in parallel or antiparallel orientations.
- Primary Structure Definition: The linear sequence of linked amino acids in a protein is known as its primary structure.
- Importance of Primary Structure: Understanding primary structure is essential as it dictates protein folding and function.
- Peptide Bond Formation: Amino acids are joined together in proteins through peptide bonds, formed by a condensation reaction between the carboxyl and amino groups.
- Polypeptide Formation: The linkage of numerous amino acids via peptide bonds results in the formation of polypeptides or proteins.
- Peptide Chain Naming Convention: The free amino end is termed the N-terminal, while the free carboxyl end is the C-terminal.
- Abnormal Sequences and Folding: Conditions causing abnormal amino acid sequences lead to improper folding, resulting in loss of function.
- Hydration of Peptide Bonds: Non-enzymatic hydrolysis of peptide bonds demands specific environmental conditions like high heat and strong solvents.
- Alpha Helix Characteristics: Each turn of an α-helix typically consists of 3.6 amino acids.
- Beta Sheet Structure: The pleated sheet structure arises from nearly fully extended polypeptide segments that engage in hydrogen bonding.
- Rotation Limitation: Free rotation around the bonds connecting α-carbons in the polypeptide chain is limited due to steric hindrance and the structure of neighboring groups.
- Reverse Polypeptide Direction: Hydrogen bonds also aid in reversing the direction of polypeptide chains, contributing to the compactness of globular structures.
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Description
Test your knowledge about protein structures with a focus on the primary, secondary, tertiary, and quaternary levels of organization. Understand how amino acids are joined together by peptide bonds to form unique three-dimensional shapes.