Questions and Answers
How many amino acids can humans produce on their own?
What is the total number of essential amino acids that humans need to obtain from food?
Which of the following correctly describes the role of dietary sources in amino acid supply?
Which statement about amino acids is true?
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Why are the nine amino acids important for humans?
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In acidic conditions, what is the predominant charge of mammalian amino acids?
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Which configuration is unique to all mammalian amino acids?
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At physiological pH, mammalian amino acids usually exist as which form?
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In a solution with a low pH, amino acids will predominantly act as which type of ion?
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What happens to the charge of mammalian amino acids when the pH of the solution increases?
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What does a high pKa value indicate about an acid's strength?
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At what situation do the groups start donating hydrogen instead of the medium?
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Which pKa value corresponds to the α-carboxylic group in glycine?
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What does PI represent in the titration curve of glycine?
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When a molecule is 100% in zwitterion form, what is true about its charge?
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Which amino acid is classified as a derivative amino acid?
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Which amino acid is not typically categorized as a derivative amino acid?
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Which of the following amino acids has a side chain that can create a positively charged group at physiological pH?
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Which amino acid is the simplest in structure and does not contain an R group that can be classified as a derivative?
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Which derivative amino acid is essential for the synthesis of neurotransmitters?
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Which amino acid is known as an essential amino acid that must be obtained from dietary sources?
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Which amino acid is a non-essential amino acid that the body can synthesize?
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What is the function of histamine in the body?
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Which of the following amino acids is considered a sulfur-containing amino acid?
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What characteristic is common to all standard amino acids?
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Study Notes
Amino Acids Overview
- Humans can produce 11 amino acids; 9 essential amino acids must be obtained from food.
- Amino acids are characterized by their basic structure, containing an α-amino group and an α-carboxylic group.
pKa Concept
- pKa (acid dissociation constant) measures an acid's ability to donate protons.
- High pKa indicates low acidity and low concentration of protons.
- pKa values for amino acid groups:
- α-amino group: 9.4
- α-carboxylic group: 2.2
Titration Curve of Glycine
- Titration curve demonstrates the relationship between the pH of a solution and the ionization of glycine.
- Key points on the curve:
- pK1: pH at which 50% of molecules are in cation form and 50% are in zwitterion form.
- pI: point where net charge of the molecule is zero.
- pK2: pH at which 50% of molecules are in anion form and 50% are in zwitterion form.
- Glycine, like all mammalian amino acids, exists primarily in L-configuration.
Acidic Medium Behavior
- In an acidic medium, amino acids are likely to exist as cations.
Buffering Action
- Buffering action is especially significant with specific amino acids, notably histidine.
Derivative Amino Acids
- Histamine is an example of a derivative amino acid.
Structural Characteristics
- The general structure of amino acids is distinguished by their unique side chains (R groups), which determine their properties and classification.
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Description
This quiz covers the basics of amino acids, including their structure and the essential amino acids necessary for human health. It also explores the pKa concept and the titration curve of glycine, illustrating how these elements relate to acid-base chemistry. Test your understanding of these fundamental biochemical topics!
