Peptide Bond quiz #1 Flashcards
Peptide Bond quiz #1
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What is a peptide bond in the context of protein structure?
A peptide bond is an amide covalent linkage formed between the carboxyl group of one amino acid and the amino group of another in a polypeptide chain. How is a peptide bond formed between two amino acids?
A peptide bond is formed through a dehydration synthesis reaction, where the carboxyl group of one amino acid reacts with the amino group of another, releasing a molecule of water. What type of reaction is peptide bond formation, and does it require energy?
Peptide bond formation is an endergonic reaction that requires energy input, typically from ATP. What is released as a byproduct during the formation of a peptide bond?
A molecule of water (H2O) is released as a byproduct during peptide bond formation. What is the reverse process of peptide bond formation called?
The reverse process is called hydrolysis, which breaks peptide bonds by adding water. Is peptide bond hydrolysis energetically favorable or unfavorable?
Peptide bond hydrolysis is energetically favorable (exergonic), releasing energy. Why are peptide bonds stable in proteins despite hydrolysis being exergonic?
Peptide bonds are stable because hydrolysis has a high energy barrier, making the reaction occur very slowly under normal conditions. How can you identify a peptide bond in a polypeptide chain?
A peptide bond can be identified as a carbonyl group (C=O) linked directly to a nitrogen atom (N) in the backbone. What is the relationship between the number of amino acids and the number of peptide bonds in a polypeptide?
The number of peptide bonds is always one less than the number of amino acids in the chain. What type of covalent bond is a peptide bond classified as?
A peptide bond is classified as an amide bond. What functional groups are involved in the formation of a peptide bond?
The carboxyl group of one amino acid and the amino group of another are involved in peptide bond formation. What is dehydration synthesis in the context of peptide bond formation?
Dehydration synthesis is the process where two molecules join by removing a water molecule, as seen in peptide bond formation. What is the significance of the alpha carbon in amino acids during peptide bond formation?
The alpha carbon is the central carbon of each amino acid, and peptide bonds link the backbone atoms adjacent to these alpha carbons. What is the energetic nature of peptide bond formation and breakdown?
Peptide bond formation is endergonic (requires energy), while breakdown (hydrolysis) is exergonic (releases energy). Why does peptide bond hydrolysis not occur rapidly in cells?
Because there is a significant energy barrier that slows down the hydrolysis reaction, making peptide bonds stable. What is the chemical structure of a peptide bond?
A peptide bond has the structure -CO-NH-, linking the carbonyl carbon of one amino acid to the nitrogen of another. What is the role of ATP in peptide bond formation?
ATP provides the energy required for the endergonic process of peptide bond formation. What happens to the reactants during peptide bond hydrolysis?
During hydrolysis, water is added, breaking the peptide bond and releasing two separate amino acids. What is an amide linkage in the context of proteins?
An amide linkage in proteins refers to the peptide bond connecting amino acids. How does the number of peptide bonds change as a polypeptide grows?
Each time a new amino acid is added, one new peptide bond is formed, so the number of peptide bonds is always one less than the number of amino acids. What is the main difference between dehydration synthesis and hydrolysis?
Dehydration synthesis forms bonds by removing water, while hydrolysis breaks bonds by adding water. What is the significance of the peptide bond in protein structure?
Peptide bonds link amino acids together, forming the primary structure of proteins. What is the directionality of peptide bond formation in proteins?
Peptide bonds form from the carboxyl end of one amino acid to the amino end of the next, giving proteins a specific directionality (N-terminus to C-terminus). What is the effect of peptide bond formation on the free energy of the system?
Peptide bond formation increases the free energy of the system, making it an endergonic process. What is the effect of peptide bond hydrolysis on the free energy of the system?
Peptide bond hydrolysis decreases the free energy of the system, making it an exergonic process. Why is peptide bond formation considered a condensation reaction?
Because it involves the joining of two molecules with the loss of a small molecule, water. What is the role of water in peptide bond hydrolysis?
Water is added to break the peptide bond, resulting in two separate amino acids. What is the chemical formula of the group released during peptide bond formation?
The group released is water, with the chemical formula H2O. What is the stability of peptide bonds under physiological conditions?
Peptide bonds are stable under physiological conditions due to the high energy barrier for hydrolysis. What is the main reason proteins do not spontaneously degrade into amino acids?
Proteins do not spontaneously degrade because peptide bond hydrolysis, though exergonic, is very slow due to a high activation energy. What is the structural feature that distinguishes a peptide bond from other covalent bonds in proteins?
A peptide bond is specifically the amide linkage between the carbonyl carbon and the nitrogen atom in the backbone. What is the importance of peptide bonds in the formation of polypeptides?
Peptide bonds are essential for linking amino acids into long polypeptide chains, forming proteins. What is the result of peptide bond hydrolysis in terms of molecular products?
Peptide bond hydrolysis results in the formation of two free amino acids. What is the energetic requirement for peptide bond formation?
Peptide bond formation requires an input of energy, typically supplied by ATP. What is the functional consequence of peptide bond rigidity in proteins?
Peptide bond rigidity restricts rotation, contributing to the overall structure and stability of proteins. What is the main chemical reaction type involved in peptide bond formation?
The main reaction type is dehydration synthesis (condensation reaction). What is the main chemical reaction type involved in peptide bond breakdown?
The main reaction type is hydrolysis. What is the relationship between peptide bond formation and protein synthesis?
Peptide bond formation is the key chemical step in protein synthesis, linking amino acids together. What is the significance of the energy barrier in peptide bond hydrolysis?
The energy barrier prevents rapid breakdown of peptide bonds, ensuring protein stability. What is the role of enzymes in peptide bond hydrolysis?
Enzymes such as proteases lower the activation energy, allowing peptide bond hydrolysis to occur more rapidly.
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