Title: Quiz: Protein Structure
Course: BTEC-2020-301-302-303-F21 > Section: Protein Structure

Q: Alpha helices are an example of which level of protein structure?
- Primary
- Secondary
- Tertiary
- Quaternary
A: Secondary
If right: Correct! Alpha helices are an example of secondary structure
If wrong: Incorrect. Review the protein structure summary.

Q: What are the building blocks of proteins?
- Amino acids
- Nucleic acids
- Enzymes
- Hormones
- Peptide bonds
A: Amino acids
If right: Correct! Amino acids are the monomers that comprise proteins.
If wrong: Incorrect. Review the chapter on protein structure.

Q: Which portion of amino acids varies?
- Amino group
- Carboxyl group
- Alpha carbon
- Side chain
- Peptide bond
A: Side chain
If right: Correct! The side chain, or R group, varies among amino acids.
If wrong: Incorrect. Review the video or chapter on protein structure.

Q: Interactions among R groups determine which level of protein structure?
- Primary
- Secondary
- Tertiary
- Quaternary
A: Tertiary
If right: Correct! R group interactions create a proteinâ€™s complex three-dimensional tertiary structure.
If wrong: Incorrect. Review the chapter on protein structure.

Q: Hydrogen bonding between carbonyl and amino groups on the protein backbone are responsible for what level of protein structure?
- Primary
- Secondary
- Tertiary
- Quaternary
A: Secondary
If right: Correct! Hydrogen bonding between carbonyl and amino groups on the protein backbone causes formation of alpha helices and beta sheets, which are secondary structure.
If wrong: Incorrect. Review the chapter on protein structure.

Q: Where are the hydrophobic R groups of a protein most likely to be found?
- In the interior of a protein
- On the surface of a protein
- In an alpha helix
- In a beta sheet
- In a quaternary structure
A: In the interior of a protein
If right: Correct! Hydrophobic R groups are likely to be in the interior of a protein, where they are shielded from water.
If wrong: Incorrect. Review the chapter on protein structure.

Q: The DNA sequence directly affects which level of protein structure?
- Primary
- Secondary
- Tertiary
- Quaternary
A: Primary
If right: Correct! The DNA sequence defines the order of amino acids, which defines primary protein structure.
If wrong: Incorrect. Review the chapter on protein structure.

Q: Why donâ€™t all proteins have quaternary structure?
- Only proteins made of two or more polypeptides have quaternary structure
- Only hormones require quaternary structure for proper functioning.
- Proteins with beta sheets cannot form quaternary structure.
- Post-translational modifications are required for quaternary structure.
- Chaperones are required for formation of quaternary structure.
A: Only proteins made of two or more polypeptides have quaternary structure
If right: Correct! Quaternary structure is formed by two or more amino acid chains.
If wrong: Incorrect. Review the chapter on protein structure.

Q: What type of bond may be formed only between two cysteines?
- Peptide bond
- Disulfide bond
- Hydrogen bond
- Ionic bond
A: Disulfide bond
If right: Correct! Disulfide bonds are formed by cysteines.
If wrong: Incorrect. Review the chapter on protein structure.

Q: What does the term denaturation mean?
- Breakage of peptide bonds
- Change of R groups
- Breakage of disulfide bonds
- Loss of protein structure
- Modification of primary structure
A: Loss of protein structure
If right: Correct! If a protein is denatured, it has lost its functional shape.
If wrong: Incorrect. Review the chapter on protein structure.

Q: Where are the hydrophilic R groups of a protein most likely to be found?
- In the interior of a protein
- On the surface of a protein
- In an alpha helix
- In a beta sheet
- In a quaternary structure
A: On the surface of a protein
If right: Correct! Hydrophilic R groups are likely to be on the surface of a protein, where they interact with water in the environment.
If wrong: Incorrect. Review the chapter on protein structure.

Q: What can cause a protein to denature? Choose all correct answers.
- Temperature changes
- pH changes
- Chemical exposure
- Chaperones
A: Temperature changes; pH changes; Chemical exposure
If right: Correct! Changes in temperature or pH, and exposure to certain chemicals, can cause proteins to denature.
If wrong: Incorrect. Review the chapter on protein structure.

Q: How do amino acids with charged R groups interact? Choose all correct answers.
- R groups with positive charges form alpha helices
- R groups with negative charges form beta sheets
- R groups with like charges repel each other
- R groups with unlike charges attract each other in ionic bonds
A: R groups with like charges repel each other; R groups with unlike charges attract each other in ionic bonds
If right: Correct! With charged R groups, like charges repel, and unlike charges repel.
If wrong: Incorrect. Review the chapter on protein structure.

Q: When a protein is denatured, which type of structure remains?
- Primary
- Secondary
- Tertiary
- Quaternary
A: Primary
If right: Correct! Primary structure is the order of amino acids, and is not affected by denaturation.
If wrong: Incorrect. Review the chapter on protein structure.

Q: Which part of an amino acid determines whether the amino acid is hydrophobic, hydrophilic, or charged?
- Amino group
- Carboxyl group
- R group
- Peptide bond
A: R group
If right: Correct! The R group, or side chain, is the variable part of an amino acid, and it defines the amino acidâ€™s type.
If wrong: Incorrect. Review the chapter on protein structure.

Q: Why does denaturation alter protein function?
- Protein function is determined by protein shape.
- Peptide bonds required for function are broken.
- The release of chaperones disrupts function.
- Disulfide bonds disrupt function.
A: Protein function is determined by protein shape.
If right: Correct! Protein shape determines protein function.
If wrong: Incorrect. Review the chapter on protein structure.