Identifying Specific Protein Structures - Biochemistry
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Which of the following structures is threonine?
Which of the following structures is threonine?
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Threonine is a polar uncharged amino acid with a 
R-group.
Threonine is a polar uncharged amino acid with a
Identify the given structure.
Identify the given structure.
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Arginine is a basic amino acid. The charge on the amine in the functional group makes this structure basic. While lysine is also a basic amino acid, it has a different R-group.
Arginine is a basic amino acid. The charge on the amine in the functional group makes this structure basic. While lysine is also a basic amino acid, it has a different R-group.
Which of the following structures is methionine?
Which of the following structures is methionine?
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Methionine is a non-polar amino acid. It is one of two amino acids that contain sulfur, the other is cysteine.
Methionine is a non-polar amino acid. It is one of two amino acids that contain sulfur, the other is cysteine.
Name the given structure.
Name the given structure.
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Leucine is a non-polar amino acid with a 
R-group.
Leucine is a non-polar amino acid with a
Which of the following sets of amino acids is most likely to be found on the interior portion of a transmembrane protein?
Which of the following sets of amino acids is most likely to be found on the interior portion of a transmembrane protein?
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The interior portion of a transmembrane protein is most likely to be populated with smaller, hydrophobic amino acids. This is because the interior of the transmembrane protein is in the hydrophobic environment of the lipid bilayer. Thus, alanine, valine, and leucine - small, hydrophobic amino acids - are most likely to be found there.
The interior portion of a transmembrane protein is most likely to be populated with smaller, hydrophobic amino acids. This is because the interior of the transmembrane protein is in the hydrophobic environment of the lipid bilayer. Thus, alanine, valine, and leucine - small, hydrophobic amino acids - are most likely to be found there.
The secondary structure of protein formation is governed by what type of bonds?
The secondary structure of protein formation is governed by what type of bonds?
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The secondary structure of a protein can be either an alpha helix or a beta pleated sheet. In either case, the structure forms due to intra-chain hydrogen bonding of the protein's backbone amino and carboxyl groups.
The secondary structure of a protein can be either an alpha helix or a beta pleated sheet. In either case, the structure forms due to intra-chain hydrogen bonding of the protein's backbone amino and carboxyl groups.
Which of the following is not present on all amino acids?
Which of the following is not present on all amino acids?
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All 20 of the amino acids have on its central carbon a hydrogen, a carboxyl group, an amino group, and a distinctive R-group. These R-groups determine the properties of the amino acid and thus the polypeptide of which they are a part.
All 20 of the amino acids have on its central carbon a hydrogen, a carboxyl group, an amino group, and a distinctive R-group. These R-groups determine the properties of the amino acid and thus the polypeptide of which they are a part.
Primary protein structure is primarily held together by what type of bond?
Primary protein structure is primarily held together by what type of bond?
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Primary protein structures are composed of amino acids linked together by peptide bonds. Secondary protein structures are held together by hydrogen bonds. Phosphodiester bonds can be found between sugar and phosphate groups in the backbone of DNA.
Primary protein structures are composed of amino acids linked together by peptide bonds. Secondary protein structures are held together by hydrogen bonds. Phosphodiester bonds can be found between sugar and phosphate groups in the backbone of DNA.
Which amino acid does this structure represent?
Which amino acid does this structure represent?
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The amino acid's R group is composed of an ethyl group, followed by a carboxylate group, and therefore represents glutamate.
The amino acid's R group is composed of an ethyl group, followed by a carboxylate group, and therefore represents glutamate.
Which amino acid does this structure represent?
Which amino acid does this structure represent?
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The amino acid's chiral carbon is connected to two methyl groups followed, by a sulfur, and finally another methyl group. Therefore, the amino acid is methionine (M).
The amino acid's chiral carbon is connected to two methyl groups followed, by a sulfur, and finally another methyl group. Therefore, the amino acid is methionine (M).
The amino acid phenylalanine is pictured. If a hydroxyl group was added to the carbon in the red box, which amino acid would the new molecule most closely resemble?
The amino acid phenylalanine is pictured. If a hydroxyl group was added to the carbon in the red box, which amino acid would the new molecule most closely resemble?
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The structure would most closely resembe tyrosine (pictured).
The structure would most closely resembe tyrosine (pictured).
If the phenyl group in the pictured molecule were removed, what amino acid would the new structure most closely resemble?
If the phenyl group in the pictured molecule were removed, what amino acid would the new structure most closely resemble?
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Alanine is the amino acid that would be formed by removing the phenyl group from phenylalanine (the pictured molecule).
Alanine is the amino acid that would be formed by removing the phenyl group from phenylalanine (the pictured molecule).
If the amide group of glutamine (pictured here) was removed and a hydroxyl group was added to the carbon bound to the alpha carbon of the resulting structure, what amino acid would be formed?
If the amide group of glutamine (pictured here) was removed and a hydroxyl group was added to the carbon bound to the alpha carbon of the resulting structure, what amino acid would be formed?
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Threonine (pictured here) would be formed.
Threonine (pictured here) would be formed.
Which of the following structures is cysteine?
Which of the following structures is cysteine?
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Cysteine is a polar amino acid with an R-group of 
. It is one of two amino acids with a sulfur in the R-group, the other is methionine.
Cysteine is a polar amino acid with an R-group of
Which of the following is a polar amino acid?
Which of the following is a polar amino acid?
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The polarity of an amino acid is determined by the R-group. The electronegativity difference between oxygen and carbon creates a dipole with the partial positive being on carbon and the partial negative being on oxygen. The dipole makes the molecule polar.
The polarity of an amino acid is determined by the R-group. The electronegativity difference between oxygen and carbon creates a dipole with the partial positive being on carbon and the partial negative being on oxygen. The dipole makes the molecule polar.
Identify the given structure.
Identify the given structure.
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Phenylalanine is a non-polar amino acid. The structure of this amino acid is literally alanine with a phenyl group attached.
Phenylalanine is a non-polar amino acid. The structure of this amino acid is literally alanine with a phenyl group attached.
Which of the following is an acidic amino acid?
Which of the following is an acidic amino acid?
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An acidic amino acid must have a carboxyl moiety 
in its R-group. Because all amino acids contain a carboxyl moiety on the alpha carbon, that acidic group does not determine whether or not the amino acid is considered acidic.
An acidic amino acid must have a carboxyl moiety
Which of the following is a basic amino acid?
Which of the following is a basic amino acid?
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Bases, according to the Bronsted-Lowry definition, are substances that accept 
Bases, according to the Bronsted-Lowry definition, are substances that accept
Identify the given amino acid.
Identify the given amino acid.
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Aspartic acid is an acidic amino acid, meaning it contains 
in its R-group. The R-group of aspartic acid is 
.
Aspartic acid is an acidic amino acid, meaning it contains
Identify the given amino acid.
Identify the given amino acid.
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Glutamine is one of two amino acids that are amides. The nitrogen bonded to a carbon-oxygen double bond makes it an amide.
Glutamine is one of two amino acids that are amides. The nitrogen bonded to a carbon-oxygen double bond makes it an amide.