Questions and Answers
Proteins are polymers of _____
amino acids
What type of bond joins the monomers in a protein's primary structure?
peptide
The secondary structure of a protein results from
hydrogen bonds
Tertiary structure is not directly dependent on
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At which bond would water need to be added to achieve hydrolysis of the dipeptide?
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Some regions of a polypeptide may coil or fold back on themselves. This is called _____, and the coils or folds are held in place by _____.
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What makes one amino acid different from another?
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Which bonds maintain the primary structure of a protein?
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The a-helix and B-pleated sheet are examples of which level of protein structure?
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What disruption occurs when lactase is transferred to pH 5?
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Interactions between the side chains (R groups) in a polypeptide are most important in stabilizing which of the following?
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What would changing a single amino acid in a protein of 325 amino acids do?
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Which of the following statements is an accurate description of proteins?
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What could happen if a genetic mutation replaced a hydrophobic amino acid in a polypeptide with a hydrophilic one?
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Which level of protein structure is a characteristic of some, but not all, proteins?
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Study Notes
Protein Structure and Function
- Proteins are made from polymers of amino acids.
- Peptide bonds link monomers in a protein's primary structure.
- The secondary structure of proteins, including α-helices and β-pleated sheets, is stabilized by hydrogen bonds.
- Tertiary structure relies primarily on interactions among side chains (R groups) and not on peptide bonds.
- Hydrolysis of dipeptides restores amino acids, necessitating the addition of water at the peptide bond.
- Regions of a polypeptide can coil or fold due to secondary structure, which is also stabilized by hydrogen bonds.
Amino Acids and Variability
- There are 20 different amino acids, distinguished by unique side chains (R groups) attached to an α carbon.
- Peptide bonds specifically maintain the primary structure of a protein.
- Altering a single amino acid in a protein can change its primary structure and may sometimes affect its biological function and tertiary structure.
Enzyme Activity and pH Dependency
- Lactase, a single polypeptide enzyme, hydrolyzes lactose into monosaccharides, functioning optimally at pH 6.
- Transferring lactase to pH 5 significantly diminishes enzyme activity, likely due to disruptions in secondary and tertiary structures.
Structural Levels of Proteins
- Interactions between side chains are crucial for stabilizing the tertiary structure of proteins.
- The primary structure refers to the sequence of amino acids defined by the genetic code in DNA.
- Quaternary structure is present in some proteins, involving the assembly of multiple polypeptides.
Impact of Mutations
- A mutation causing a hydrophobic amino acid to convert to a hydrophilic one can disrupt protein interactions leading to altered protein shape and function.
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Description
Test your knowledge on proteins with these flashcards from Biology Chapter 3 B. Each card covers essential concepts such as amino acids, peptide bonds, and protein structures. Ideal for quick revision or in-depth understanding of protein biology.
