Amino Acid Structure Overview
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Questions and Answers

What is the basic structure of an amino acid?

  • Amino group and carboxyl group attached to a central nitrogen atom
  • Amino group and carboxyl group attached to a central oxygen atom
  • Amino group, carboxyl group, and R group attached to a central nitrogen atom
  • Amino group, carboxyl group, and R group attached to a central carbon atom (correct)

    • What is the function of amino acids in the body?

  • Transport of oxygen in the blood and removal of carbon dioxide
  • Energy storage and structural support for cells
  • Regulation of gene expression and DNA replication
  • Building blocks of proteins and catalysts for chemical reactions (correct)

    • What are proteins primarily responsible for in the cell?

  • Storing genetic information and transmitting signals
  • Catalysing chemical reactions and providing structural elements (correct)
  • Facilitating cellular respiration and energy production
  • Regulating cell growth and division

    • What is unique to each amino acid?

    <p>The organic R group (or side chain)</p> Signup and view all the answers

    Which functional groups are present in every amino acid molecule?

    <p>Amino group (−NH2) and carboxyl group (−COOH)</p> Signup and view all the answers

    What type of bond does the α-carbon atom of an amino acid typically form with the R group?

    <p>Covalent bond</p> Signup and view all the answers

    What is the primary function of proteins in the cell?

    <p>Catalyze chemical reactions</p> Signup and view all the answers

    What is the significance of the α-carbon atom in an amino acid?

    <p>It is the central carbon to which both an amino and a carboxyl group are attached</p> Signup and view all the answers

    Which of the following is a function of proteins in the cell?

    <p>Catalysing chemical reactions</p> Signup and view all the answers

    What is the role of antibodies in the form of proteins?

    <p>Protecting animals from disease</p> Signup and view all the answers

    Which statement about proteins is accurate?

    <p>They help bind cells together into tissues</p> Signup and view all the answers

    What is the function of interferon, a form of protein?

    <p>Mounting an intracellular attack against viruses</p> Signup and view all the answers

    What is a key role of proteins in gene expression?

    <p>Controlling the activity of genes</p> Signup and view all the answers

    What is the primary function of interferon, a form of protein?

    <p>Mount an intracellular attack against viruses</p> Signup and view all the answers

    Which statement about the role of proteins in gene expression is accurate?

    <p>Proteins control the activity of genes</p> Signup and view all the answers

    What is a key role of proteins in binding cells together into tissues?

    <p>Providing structural elements</p> Signup and view all the answers

    What do proteins primarily protect animals from, when in the form of antibodies?

    <p>Disease</p> Signup and view all the answers

    What is the main function of proteins in enabling movement?

    <p>Acting as contractile elements</p> Signup and view all the answers

    How many different combinations of proteins are possible with 20 amino acids when considering a dipeptide made of just two amino acids joined together?

    <p>$20^2 = 400$</p> Signup and view all the answers

    What is the formula to calculate the number of different combinations possible with 20 amino acids for a protein with n amino acids in the chain?

    <p>$20^n$</p> Signup and view all the answers

    What type of reaction links together amino acids to form proteins?

    <p>Condensation reaction</p> Signup and view all the answers

    What gives each protein a characteristic and unique sequence of amino acids?

    <p>Linking together amino acids</p> Signup and view all the answers

    What is the formula to calculate the number of different combinations possible with 20 amino acids for a protein with $n$ amino acids in the chain?

    <p>$20^n$</p> Signup and view all the answers

    If a protein has a chain of 4 amino acids, how many different combinations are possible with 20 amino acids?

    <p>$20^4 = 160,000$</p> Signup and view all the answers

    What does a dipeptide made of just two amino acids joined together yield in terms of different combinations?

    <p>$400$</p> Signup and view all the answers

    If a protein has a chain of 6 amino acids, how many different combinations are possible with 20 amino acids?

    <p>$20^6 = 64,000,000$</p> Signup and view all the answers

    What is the significance of the unique sequence of amino acids in a protein?

    <p>It dictates the 3-D conformation the folded protein will have</p> Signup and view all the answers

    Which level of protein structure is primarily responsible for giving identity and characteristics to a protein?

    <p>Primary structure</p> Signup and view all the answers

    What determines the shape of a protein?

    <p>Local interactions between parts of the polypeptide backbone</p> Signup and view all the answers

    What allows amino acids to interact with each other that are not close in primary structure?

    <p>Tertiary structure</p> Signup and view all the answers

    What is the primary distinction between the terms 'polypeptide' and 'protein'?

    <p>Polypeptide may or may not have folded into its final, functional form, while protein generally refers to a folded, functional molecule.</p> Signup and view all the answers

    When is the term 'protein' generally used?

    <p>To refer to a folded, functional molecule that may have one or more subunits.</p> Signup and view all the answers

    What does the term 'polypeptide' specifically refer to?

    <p>A single polymer of amino acids that may or may not have folded into its final, functional form.</p> Signup and view all the answers

    What is the primary distinction between the terms 'polypeptide' and 'protein'?

    <p>Protein generally refers to a functional, folded molecule, while polypeptide may or may not have folded into its final, functional form</p> Signup and view all the answers

    What allows amino acids to interact with each other that are not close in primary structure?

    <p>Disulfide bonds between cysteine R groups</p> Signup and view all the answers

    What determines the shape of a protein?

    <p>The sequence of amino acids in its primary structure</p> Signup and view all the answers

    What allows proteins to be amazing catalysts and adapt to, respond to, and pass on signals upon binding of other molecules or proteins?

    <p>Flexibility in structure</p> Signup and view all the answers

    What happens if the structure of a protein is altered?

    <p>The function is usually lost, but not always</p> Signup and view all the answers

    What characteristic defines proteins in terms of structure?

    <p>Infinite flexibility</p> Signup and view all the answers

    What allows proteins to be amazing catalysts and adapt to, respond to, and pass on signals upon binding of other molecules or proteins?

    <p>Infinite flexibility</p> Signup and view all the answers

    What happens if the structure of a protein is altered?

    <p>It loses all function</p> Signup and view all the answers

    What is the primary distinction between the terms 'polypeptide' and 'protein'?

    <p>'Polypeptide' refers to a single amino acid chain while 'protein' can have multiple chains</p> Signup and view all the answers

    What is the end of the protein that contains the only free α-carboxyl group called?

    <p>Carboxyl terminus</p> Signup and view all the answers

    Where does the synthesis of proteins occur?

    <p>Ribosomes</p> Signup and view all the answers

    How does the synthesis of proteins proceed?

    <p>By joining the carboxyl terminus of the first amino acid to the amino terminus of the next one</p> Signup and view all the answers

    What is the end of the protein that has the free α-amino group referred to as?

    <p>Amino terminus</p> Signup and view all the answers

    Where does the synthesis of proteins occur?

    <p>Ribosomes</p> Signup and view all the answers

    What is the primary function of the carboxyl terminus in a protein?

    <p>Containing the free α-carboxyl group</p> Signup and view all the answers

    What is the primary reason for arranging R-groups in an alternating orientation on either side of the polypeptide chain?

    <p>To prevent steric hindrance between consecutive R-groups</p> Signup and view all the answers

    What can occur when consecutive R-groups are oriented on the same side of a peptide backbone?

    <p>Steric hindrance</p> Signup and view all the answers

    What is the significance of organizing R-groups in an alternating orientation on either side of the polypeptide chain?

    <p>Preventing steric hindrance between consecutive R-groups</p> Signup and view all the answers

    Why is the organization of R-groups in a protein not random?

    <p>To prevent steric hindrance between consecutive R-groups on the same side of the peptide backbone</p> Signup and view all the answers

    What is the primary consequence of consecutive R-groups being oriented on the same side of a peptide backbone?

    <p>Steric hindrance</p> Signup and view all the answers

    In what manner are sequential R-groups arranged around a peptide bond?

    <p>In an alternating orientation on either side of the polypeptide chain</p> Signup and view all the answers

    What is the primary determinant of the overall conformation of a protein?

    <p>Primary structure</p> Signup and view all the answers

    What directly specifies the sequence of amino acids in proteins?

    <p>Codons in DNA</p> Signup and view all the answers

    What is the result of mutation and selection over evolutionary time?

    <p>Primary structure of proteins</p> Signup and view all the answers

    What are regions of DNA specifying proteins known as?

    <p>'Coding' regions</p> Signup and view all the answers

    What is the ultimate determinant of the overall conformation of a protein?

    <p>Primary structure</p> Signup and view all the answers

    What directly specifies the sequence of amino acids in proteins?

    <p>mRNA</p> Signup and view all the answers

    What are regions of DNA specifying proteins known as?

    <p>Exons</p> Signup and view all the answers

    What arrived at the current state of the primary structure of any protein?

    <p>Mutation and selection over evolutionary time</p> Signup and view all the answers

    What is the primary determinant of the overall conformation of a protein?

    <p>Primary structure</p> Signup and view all the answers

    What directly specifies the sequence of amino acids in proteins?

    <p>messenger RNA</p> Signup and view all the answers

    What are regions of DNA specifying proteins known as?

    <p>Exons</p> Signup and view all the answers

    What is the result of mutation and selection over evolutionary time?

    <p>Change in primary structure</p> Signup and view all the answers

    What gives rise to the properties a protein has?

    <p>Sequence of amino acids</p> Signup and view all the answers

    At the tertiary level of protein structure, what plays a role in folding?

    <p>Interactions among the polypeptide backbone and amino acid side groups</p> Signup and view all the answers

    What brings amino acids close together that are not near each other in primary structure?

    <p>Secondary structure formation</p> Signup and view all the answers

    What gives rise to folds that bring amino acids close together that are not near each other in primary structure?

    <p>Interactions among the R-groups of the amino acids</p> Signup and view all the answers

    What is the primary role of the sequence of amino acids in determining a protein's properties?

    <p>It gives rise to all of the properties a protein has</p> Signup and view all the answers

    Which level of protein structure involves individual components of secondary structure interacting with each other?

    <p>Tertiary structure</p> Signup and view all the answers

    What stabilizes a globular protein?

    <p>Ionic interactions, hydrogen bonding, and hydrophobic forces</p> Signup and view all the answers

    What treatments can cause a protein to unfold and lose its structure and function?

    <p>Heat, pH changes, detergents, and urea</p> Signup and view all the answers

    What gives rise to distinct 3-D shapes in non-fibrous proteins?

    <p>Protein folding</p> Signup and view all the answers

    Which of the following is a force that stabilizes a globular protein?

    <p>Van der Waals forces</p> Signup and view all the answers

    What effect do treatments like heat, pH changes, detergents, and urea have on a globular protein?

    <p>Cause the protein to unfold</p> Signup and view all the answers

    What gives rise to distinct 3-D shapes in non-fibrous proteins?

    <p>Folding of the proteins</p> Signup and view all the answers

    Which force stabilizes protein structure as a result of interactions that favour the exclusion of water?

    <p>Van der Waals forces</p> Signup and view all the answers

    What type of bonds are made when two sulfhydryl side-chains of cysteine are brought into close proximity?

    <p>Disulfide bonds</p> Signup and view all the answers

    Which force arises as a result of ionization of R-groups in the amino acids comprising a protein?

    <p>Ionic interactions</p> Signup and view all the answers

    What kind of forces can give rise to regular repeating structures, such as helices or pleats, in proteins?

    <p>Hydrogen bonds</p> Signup and view all the answers

    What type of bond is made when two sulfhydryl side-chains of cysteine are brought into close proximity?

    <p>Disulfide bond</p> Signup and view all the answers

    What type of interactions stabilize protein structure as a result of interactions that favor the exclusion of water?

    <p>Hydrophobic forces</p> Signup and view all the answers

    What type of forces are generally weak in comparison to covalent bonds and are dynamic due to the fluctuating nature of the attraction?

    <p>Van der Waals forces</p> Signup and view all the answers

    Which force between amino acids that are close to each other in primary structure can give rise to regular repeating structures, such as helices or pleats, in proteins?

    <p>Hydrogen bonds</p> Signup and view all the answers

    Which force arises as a result of ionization of R-groups in the amino acids comprising a protein?

    <p>Ionic interactions</p> Signup and view all the answers

    What is the term used to describe various weak interactions that are generally weak in comparison to covalent bonds?

    <p>Van der Waals forces</p> Signup and view all the answers

    What type of bond can give great strength to the overall protein structure when two sulfhydryl side-chains of cysteine are brought into close proximity?

    <p>Disulfide bond</p> Signup and view all the answers

    Which force stabilizes protein structure as a result of interactions favoring the exclusion of water?

    <p>Hydrophobic forces</p> Signup and view all the answers

    What type of forces stabilize protein structure as a result of interactions that favor the exclusion of water?

    <p>Van der Waals forces</p> Signup and view all the answers

    Which type of bond is made when two sulfhydryl side-chains of cysteine are brought into close proximity, covalently joining different protein regions and giving great strength to the overall structure?

    <p>Disulfide bonds</p> Signup and view all the answers

    Which force arises as a result of ionization of R-groups in the amino acids comprising a protein?

    <p>Ionic interactions</p> Signup and view all the answers

    What kind of forces can give rise to regular repeating structures, such as helices or pleats, in proteins?

    <p>Hydrogen bonds</p> Signup and view all the answers

    Which type of interaction favors the exclusion of water and stabilizes protein structure?

    <p>Hydrogen bonds</p> Signup and view all the answers

    What term is used to describe various weak interactions that are generally weak in comparison to covalent bonds?

    <p>Hydrogen bonds</p> Signup and view all the answers

    What gives great strength to the overall protein structure when two sulfhydryl side-chains of cysteine are brought into close proximity?

    <p>Disulfide bonds</p> Signup and view all the answers

    Which force is dynamic due to the fluctuating nature of the attraction and is generally weak in comparison to covalent bonds?

    <p>Van der Waals forces</p> Signup and view all the answers

    What might be a consequence of protein misfolding?

    <p>Inactivation of the protein</p> Signup and view all the answers

    Which diseases are associated with protein misfolding?

    <p>Mad Cow Disease, Alzheimers, and Parkinson’s Disease</p> Signup and view all the answers

    Which tissue is often affected by misfolding diseases?

    <p>Brain tissue</p> Signup and view all the answers

    What might be a consequence of protein misfolding?

    <p>Inactivation of the protein</p> Signup and view all the answers

    Which diseases are associated with protein misfolding?

    <p>Mad Cow Disease, Alzheimers, and Parkinson’s Disease</p> Signup and view all the answers

    Which tissue is often affected by misfolding diseases?

    <p>Brain tissue</p> Signup and view all the answers

    What are the two classes of proteins used by cells to facilitate proper folding of proteins?

    <p>Chaperones and chaperonins</p> Signup and view all the answers

    Why do cells expend energy to facilitate the proper folding of proteins?

    <p>To prevent diseases associated with misfolded proteins</p> Signup and view all the answers

    What is the primary role of molecular chaperones in cells?

    <p>Facilitate the proper folding of proteins</p> Signup and view all the answers

    What is a key characteristic of proteins with quaternary structure?

    <p>They arise as a result of interactions between multiple polypeptides</p> Signup and view all the answers

    Which protein demonstrates quaternary structure?

    <p>Adult hemoglobin</p> Signup and view all the answers

    How do myoglobin and hemoglobin differ in terms of subunit structure?

    <p>Myoglobin has a single subunit, while hemoglobin has multiple subunits</p> Signup and view all the answers

    What gives rise to differences in the behavior towards oxygen between myoglobin and hemoglobin?

    <p>Hemoglobin's multiple subunits compared to myoglobin's single subunit</p> Signup and view all the answers

    What is the primary difference between myoglobin and hemoglobin in terms of structure?

    <p>Myoglobin lacks quaternary structure, while hemoglobin has quaternary structure</p> Signup and view all the answers

    What is a key characteristic of proteins with quaternary structure?

    <p>They are composed of multiple polypeptides</p> Signup and view all the answers

    What gives rise to differences in the behavior towards oxygen between myoglobin and hemoglobin?

    <p>Quaternary structure</p> Signup and view all the answers

    Which protein demonstrates quaternary structure?

    <p>Adult hemoglobin</p> Signup and view all the answers

    What is the primary distinction between myoglobin and hemoglobin?

    <p>Subunit structure</p> Signup and view all the answers

    What allows proteins to be amazing catalysts and adapt to, respond to, and pass on signals upon binding of other molecules or proteins?

    <p>Distinct 3-D shapes in non-fibrous proteins</p> Signup and view all the answers

    Which amino acid is known for its unique ability to function in both acid and base catalysis near physiological pH values?

    <p>Histidine</p> Signup and view all the answers

    Which group of amino acids are often found clustered on the surface of globular proteins in aqueous solutions due to their hydrophilic nature?

    <p>Group IV: Basic Amino Acids</p> Signup and view all the answers

    Which amino acid is most often found in the active sites of protein enzymes?

    <p>Histidine</p> Signup and view all the answers

    Which chemical property sets histidine apart from the other standard amino acids?

    <p>Ability to function in acid and base catalysis</p> Signup and view all the answers

    Which type of amino acids are precursors of nitrogenous base components of nucleotides and nucleic acids?

    <p>'Nonstandard' Amino Acids</p> Signup and view all the answers

    Which amino acid derivative acts as a neurotransmitter?

    <p>Serotonin (derived from tryptophan)</p> Signup and view all the answers

    Which type of amino acids are often found clustered on the surface of globular proteins in aqueous solutions?

    <p>Basic Amino Acids</p> Signup and view all the answers

    Which chemical reaction is particularly important due to its effect on protein structure?

    <p>Peptide bond reaction</p> Signup and view all the answers

    What is the primary role of heme, a complex amino-acid derived cofactor?

    <p>Participating in oxygen transport and storage</p> Signup and view all the answers

    What distinguishes nonstandard amino acids from standard amino acids?

    <p>They have unique side chains not found in standard amino acids.</p> Signup and view all the answers

    Which group of amino acids is characterized as hydrophobic?

    <p>Glycine, alanine, valine, leucine</p> Signup and view all the answers

    Which amino acids possess functional groups with electron pairs available for hydrogen bonding to water and other molecules?

    <p>Serine, cysteine, threonine</p> Signup and view all the answers

    Which amino acids have a carboxylic acid on their side chains that gives them acidic properties?

    <p>Aspartic acid, glutamic acid</p> Signup and view all the answers

    Which group of amino acids plays a central role in amino acid metabolism?

    <p>Glutamate, glutamine</p> Signup and view all the answers

    Which type of amino acids will ionize in an aqueous solution at physiological pH?

    <p>Aspartic acid, glutamic acid</p> Signup and view all the answers

    Which group of amino acids has R groups possessing a spectrum of functional groups?

    <p>Serine, cysteine</p> Signup and view all the answers

    Which group of amino acids has either aliphatic or aromatic R groups?

    <p>Valine, leucine</p> Signup and view all the answers

    Which group of amino acids is characterized by being hydrophobic ('water fearing')?

    <p>Valinie , leucinie</p> Signup and view all the answers

    Which group of amino acids has side chains that will fold into a three-dimensional shape to bury hydrophobic side chains in the protein interior in aqueous solutions?

    <p>Valinie , leucinie</p> Signup and view all the answers

    Which group of amino acids possess at least one atom (nitrogen,oxygen,sulfur) with electron pairs available for hydrogen bonding to water and other molecules?

    <p>Serine, cysteine, threonine</p> Signup and view all the answers

    Which amino acid is known for its ability to function in both acid and base catalysis near physiological pH values?

    <p>Histidine</p> Signup and view all the answers

    What is the most abundant excitatory neurotransmitter in the central nervous system?

    <p>Glutamate</p> Signup and view all the answers

    Which group of amino acids are often found clustered on the surface of globular proteins in aqueous solutions?

    <p>Group IV: Basic Amino Acids</p> Signup and view all the answers

    Which amino acid is most often found in the active sites of protein enzymes?

    <p>Histidine</p> Signup and view all the answers

    Which amino acid is a precursor of serotonin and melatonin, and synthesized from histidine?

    <p>Tryptophan</p> Signup and view all the answers

    Which type of amino acids refers to those that have been chemically modified after incorporation into a protein?

    <p>Nonstandard Amino Acids</p> Signup and view all the answers

    Which group of amino acids possess at least one atom with electron pairs available for hydrogen bonding to water and other molecules?

    <p>Group II: Polar Amino Acids</p> Signup and view all the answers

    What is the primary role of the sequence of amino acids in determining a protein's properties?

    <p>Determining all properties</p> Signup and view all the answers

    What are some precursors of a variety of complex nitrogen-containing molecules?

    <p>Amino acids</p> Signup and view all the answers

    What type of forces can give rise to regular repeating structures, such as helices or pleats, in proteins?

    <p>Hydrogen bonds</p> Signup and view all the answers

    Which group of amino acids has side chains that are hydrophobic ('water fearing')?

    <p>Group I: Nonpolar amino acids</p> Signup and view all the answers

    Which group of amino acids possess at least one atom (nitrogen, oxygen, sulfur) with electron pairs available for hydrogen bonding to water and other molecules?

    <p>Group II: Polar, Uncharged Amino Acids</p> Signup and view all the answers

    Which two amino acids have carboxylic acid on their side chains, giving them acidic (proton-donating) properties?

    <p>Aspartic acid and glutamic acid</p> Signup and view all the answers

    Which group of amino acids will ionize in an aqueous solution at physiological pH, giving an overall charge of −1?

    <p>Group III: Acidic amino acids</p> Signup and view all the answers

    What type of functional groups do most amino acids in Group II possess?

    <p>At least one atom (nitrogen, oxygen, or sulfur) with electron pairs available for hydrogen bonding</p> Signup and view all the answers

    What is the primary characteristic of Group I amino acids?

    <p>They are hydrophobic.</p> Signup and view all the answers

    What is the distinguishing feature of Group III acidic amino acids?

    <p>They possess carboxylic acid on their side chains.</p> Signup and view all the answers

    What is the primary property of Group II polar, uncharged amino acids in aqueous solutions?

    <p>Their R groups can form hydrogen bonds with water.</p> Signup and view all the answers

    Which amino acid is known for its unique ability to function in both acid and base catalysis near physiological pH values?

    <p>Histidine</p> Signup and view all the answers

    Which group of amino acids possess at least one atom with electron pairs available for hydrogen bonding to water and other molecules?

    <p>Group II: Polar, Uncharged Amino Acids</p> Signup and view all the answers

    Which amino acid is most often found in the active sites of protein enzymes?

    <p>Histidine</p> Signup and view all the answers

    What type of amino acids are often found clustered on the surface of globular proteins in aqueous solutions?

    <p>Polar Amino Acids</p> Signup and view all the answers

    What are nonstandard amino acids known for?

    <p>Being chemically modified after incorporation into a protein</p> Signup and view all the answers

    What is the primary role of Group II amino acids in proteins?

    <p>Forming hydrogen bonds with water and other molecules</p> Signup and view all the answers

    What is the significance of histidine's imidazole side chain?

    <p>It allows histidine to function in both acid and base catalysis near physiological pH values</p> Signup and view all the answers

    What is the primary function of arginine, histidine, and lysine?

    <p>Participating in acid and base catalysis near physiological pH values</p> Signup and view all the answers

    What are some prominent nitrogen-containing molecules that amino acids are precursors of?

    <p>Nucleotides and nucleic acids (DNA and RNA)</p> Signup and view all the answers

    What kind of reactions can amino acids undergo via their various chemical functionalities?

    <p>Numerous chemical reactions including peptide bond formation and cysteine oxidation</p> Signup and view all the answers

    Which group of amino acids is characterized by having side chains with electron pairs available for hydrogen bonding to water and other molecules?

    <p>Group II: Polar, Uncharged Amino Acids</p> Signup and view all the answers

    Which amino acid group has R groups that are hydrophobic ('water fearing') due to their aliphatic or aromatic nature?

    <p>Group I: Nonpolar amino acids</p> Signup and view all the answers

    Which two amino acids have carboxylic acid on their side chains that give them acidic (proton-donating) properties?

    <p>Aspartic acid and glutamic acid</p> Signup and view all the answers

    Which group of amino acids possess at least one atom (nitrogen, oxygen, or sulfur) with electron pairs available for hydrogen bonding to water and other molecules?

    <p>Group II: Polar, Uncharged Amino Acids</p> Signup and view all the answers

    What is the charge of the acidic amino acids aspartate and glutamate in an aqueous solution at physiological pH?

    <p>-1</p> Signup and view all the answers

    What type of R groups do nonpolar amino acids in Group I have that makes them hydrophobic?

    <p>Aliphatic or aromatic R groups</p> Signup and view all the answers

    What is the primary distinguishing characteristic of polar, uncharged amino acids in Group II?

    <p>Their R groups are hydrophilic ('water loving')</p> Signup and view all the answers

    What property of the side chains of nonpolar amino acids in Group I leads to their burial in the protein interior in aqueous solutions?

    <p>Aromatic or aliphatic nature of the side chains</p> Signup and view all the answers

    What role do polar, uncharged amino acids play in the folding of globular proteins in aqueous solutions?

    <p>They stabilize the folded structure through hydrogen bonding and van der Waals interactions</p> Signup and view all the answers

    Which amino acid is capable of functioning in both acid and base catalysis near physiological pH values?

    <p>Histidine</p> Signup and view all the answers

    Which group of amino acids is often found clustered on the surface of globular proteins in aqueous solutions?

    <p>Group IV: Basic Amino Acids</p> Signup and view all the answers

    Which amino acid group is characterized by having side chains with electron pairs available for hydrogen bonding to water and other molecules?

    <p>Group II: Polar, Uncharged Amino Acids</p> Signup and view all the answers

    Which reaction is particularly important due to its effect on protein structure?

    <p>Peptide bond formation</p> Signup and view all the answers

    Which complex nitrogen-containing molecule are amino acids precursors of?

    <p>Nucleotides and nucleic acids (DNA and RNA)</p> Signup and view all the answers

    Which amino acid is a precursor of serotonin and melatonin, and synthesized from histidine?

    <p>Histidine</p> Signup and view all the answers

    What is the primary reason for arranging R-groups in an alternating orientation on either side of the polypeptide chain?

    <p>To enhance hydrophobic interactions</p> Signup and view all the answers

    What are nonstandard amino acids primarily referred to as?

    <p>Amino acids that occur in living organisms but are not found in proteins</p> Signup and view all the answers

    What is the primary role of heme, a complex amino-acid derived cofactor?

    <p>Facilitating oxygen transport in hemoglobin and myoglobin</p> Signup and view all the answers

    What gives rise to folds that bring amino acids close together that are not near each other in primary structure?

    <p>Disulfide bonds between cysteine residues</p> Signup and view all the answers

    Which group of amino acids has R groups that are hydrophobic ('water fearing') due to their aliphatic or aromatic nature?

    <p>Group I: Nonpolar amino acids</p> Signup and view all the answers

    Which type of amino acids will ionize in an aqueous solution at physiological pH?

    <p>Group III: Acidic amino acids</p> Signup and view all the answers

    What is the distinguishing feature of Group III acidic amino acids?

    <p>They have a carboxylic acid on their side chain</p> Signup and view all the answers

    Which group of amino acids possess at least one atom with electron pairs available for hydrogen bonding to water and other molecules?

    <p>Group II: Polar, Uncharged Amino Acids</p> Signup and view all the answers

    What directly specifies the sequence of amino acids in proteins?

    <p>DNA</p> Signup and view all the answers

    Which force stabilizes protein structure as a result of interactions favoring the exclusion of water?

    <p>Hydrophobic interactions</p> Signup and view all the answers

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