87 Questions
Which protein component is the primary structure of hair, nails, and skin?
Keratins
What type of interactions primarily hold the subunits together in a protein's quaternary structure?
Hydrogen bonds
How does the binding of oxygen to one subunit affect the other subunits in hemoglobin?
Increases their oxygen affinity
What determines the rigidity of the fibrous protein component of hair, nails, and skin?
Presence of disulfide bonds between α-Helix structures
What feature of proteins allows them to interact with other molecules and perform unique functions?
Tertiary structure
Which protein structure consists of beta strands linked laterally by hydrogen bonds?
Parallel β-sheets
What makes antiparallel beta-sheets slightly more stable than parallel beta-sheets?
More optimum hydrogen bonding structure
Which level of protein structure deals with the association of several protein chains or subunits into a closely packed arrangement?
Quaternary structure
Which protein consists of an insoluble component present in silk, made by spiders and certain moths?
Fibroin
What is the main function of the quaternary structure in proteins like hemoglobin?
Increasing affinity for oxygen through cooperative binding
What type of bond is formed between 2 thiol groups (S-H) in protein structure?
Disulfide bridge
Which interaction is typically located on the outer part of the protein structure, towards the aqueous environment?
Hydrophilic interactions
What type of interactions stabilize the quaternary structure of proteins?
Hydrogen bonds and hydrophobic interactions
Which type of proteins assist in the folding of other proteins?
Chaperones
What kind of proteins are involved in repairing and refolding damaged proteins?
Hsp70 proteins
Which type of bond between amino acids is considered WEAK in protein structure?
Hydrogen bond
What is the fate of correctly folded proteins after ATP binding in the protein folding cycle?
They are released.
Which process usually corrects misfolded proteins in the cell?
Chaperones
What can happen if quality control systems fail to correct misfolded proteins in the cell?
Misfolded proteins accumulate
What is unique about prions among misfolded proteins?
They can transmit their misfolded shape to normal proteins
In what way do prion diseases differ from other proteinopathies?
They involve toxic misfolding and clumping of the prion protein
What is the primary outcome of protein denaturation?
Unfolding and disorganization of secondary and tertiary structures
Which type of proteins have a phosphoric acid prosthetic group?
Nucleoproteins
Which proteins have lipid as their prosthetic group?
Lipoproteins
Which proteins are responsible for transporting materials in cells and forming channels?
Transport proteins
What is the function of structural proteins in the body?
Forming connective tissues
Which type of proteins reduce activation energy of reactants and speed up reactions?
Enzymes
What type of prosthetic group is found in Hemocyanin, a protein responsible for transporting oxygen in crustaceans?
Metal ions
What type of bond is formed between two thiol groups (S-H) in protein structure?
Disulfide bridge
Which type of interactions between hydrophobic amino acid side chains can be relatively strong?
Hydrophobic interactions
What stabilizes the quaternary structure of proteins through interactions between amino acid side chains of each subunit?
Hydrogen bonds
What type of proteins assist in protein folding and may require assistance from chaperones or Heat shock proteins?
Chaperones
What is a common feature of Heat shock proteins (Hsp) that aids in their function during protein folding?
High activity at high temperatures
Which type of bonds are stronger than hydrogen bonds but weaker than disulfide bridges in protein structures?
Ionic bonds
What type of bonds hold the amino acids together in a polypeptide chain's primary structure?
Peptide bonds
Which conditions are peptide bonds resistant to, making them difficult to break?
Strong acids and bases
What type of bonds stabilize the secondary structures of proteins like α-helices and β-sheets?
Hydrogen bonds
In the α-helix secondary structure, where do the hydrogen bonds form between amino acid residues?
Across four amino acids in the spiral structure
What is the primary reason for the side chains of amino acids in α-helices extending outward?
To avoid interference between adjacent chains
Which common secondary structure of proteins involves a tightly packed, coiled polypeptide chain core?
α-Helix
What do Phosphoproteins have as their prosthetic group?
Phosphoric acid
Which enzyme is an example of a Flavoprotein?
DNA Polymerase
Which type of proteins are responsible for transporting oxygen in crustaceans?
Metalloproteins
Which protein is NOT a component of connective tissue?
Myoglobin
Which is a function of transport proteins?
Transport materials in cells
What type of protein is Insulin classified as?
Hormone
What type of agents can denature proteins?
Low pH
Which type of proteins have a spherical/globular shape?
Conjugated proteins
What is the primary function of proteins in physiological changes?
Mediation of physiological changes
Which type of proteins are characterized by long parallel polypeptide chains and cross-linkages?
Simple proteins
What is the function of fibrous proteins in the cell?
Perform structural functions
Which classification of proteins contains non-amino acid components essential for biological function?
Conjugated proteins
What is the primary function of -bends in protein secondary structure?
Reverse the direction of a polypeptide chain
What is the main role of -turns in protein folding?
Change the direction of the protein chain
In protein tertiary structure, what are domains primarily responsible for?
Forming the functional and structural units
What characterizes the tertiary structure of proteins?
The arrangement of domains in space
What is a key feature of protein tertiary structure?
Arrangement of protein secondary structures
Why are protein domains crucial in tertiary structure?
To ensure proper protein folding
What type of bonds link amino acids in a polypeptide chain's primary structure?
Peptide bonds
Which conditions are peptide bonds resistant to, making them difficult to break?
Strong acids or bases at elevated temperatures
What stabilizes the secondary structure of proteins through hydrogen bonds between adjacent amino acid residues?
Salt bridges
Which common secondary structure of proteins involves a spiral structure with hydrogen bonds between carboxy O groups and amino H groups?
α-Helix
What is the primary outcome of protein denaturation?
Loss of protein's biological function
Which type of interactions primarily hold the subunits together in a protein's quaternary structure?
Hydrogen bonds
What is the primary function of the quaternary structure in proteins like hemoglobin?
Facilitating oxygen binding and transport
What type of bond stabilizes the secondary structures of proteins like α-helices and β-sheets?
Hydrogen bonds
How are amino acids joined in a polypeptide chain's primary structure?
Peptide bonds
What holds the amino acids together in a polypeptide chain's tertiary structure?
Hydrophobic interactions
Which interaction is typically located on the outer part of the protein structure, towards the aqueous environment?
Hydrophobic interactions
What type of proteins are characterized by long parallel polypeptide chains and cross-linkages?
Fibrous proteins
What type of bond stabilizes the tertiary structure of proteins?
Disulfide bridges between thiol groups
Which type of protein consists of only amino acids and has a relatively simple structure?
Simple proteins
Which interaction typically occurs on the outer part of the protein towards the aqueous environment?
Hydrogen bonds
What is the primary function of fibrous proteins in the cell?
Perform structural functions
What type of bond is stronger than hydrogen bonds but weaker than disulfide bridges in protein structures?
Ionic bonds
Which proteins are formed from multiple copies of subunits in a polymeric arrangement?
Hemoglobin and catalase
Which type of bond is formed between two thiol groups (S-H) in protein structure?
Disulfide bond
What is the outcome of protein denaturation?
Secondary structure disruption
What type of protein aids in correcting misfolded proteins and prevents protein aggregates?
Heat shock proteins (Hsp)
Which type of proteins are soluble in water and have a spherical/globular shape?
Globular proteins
Which component stabilizes the quaternary structure of proteins through interactions between amino acid side chains of each subunit?
Hydrogen bonds
Which type of proteins are responsible for transporting materials in cells and forming channels?
Transport proteins
What type of prosthetic group is characteristic of Hemoglobin?
Pigment or chrome
Which proteins are primarily components of connective tissue, bone, tendons, skin, feathers, nail, hair, and horn?
Structural proteins
What is the function of Flavoproteins based on the provided information?
Involved in electron transport system
Which prosthetic group is found in Lipoproteins according to the text provided?
Lipid
The role of Nucleoproteins involves the presence of which prosthetic group?
Nucleic acid
Learn about the primary and secondary protein structures, focusing on α-helix and pleated beta sheet. Discover the key components of these structures and their roles in fibrous proteins like keratins. Image source: Wikiwand.
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