Chapter 3.2.4 (Exam 1) Denaturation Flashcards
Proteins Are Polymers with Highly Variable Structures
What happens if a protein is heated?
If a protein is heated, secondary and tertiary structure break down; the protein is said to be denatured
What conditions can affect secondary and tertiary structure?
High temperature
pH changes
High concentrations of polar molecules
Nonpolar substances, via hydrophobic interactions
Describe quaternary structure.
Quaternary structure results from interaction of subunits by hydrophobic interactions, van der Waals forces, ionic attractions, and hydrogen bonds
Proteins have two or more polypeptide chains, or subunits
Each subunit has its own unique tertiary structure
Proteins bind _____________ with specific molecules.
noncovalently
What is molecule specificity determined by?
Shape—there must be a general “fit” between the protein and the other molecule
Chemistry—surface R groups interact with other molecules via ionic, hydrophobic, or hydrogen bonds
What can protein shape change as a result of?
Interaction with other molecules
Covalent modification
How does protein shape change as a result of interaction with other molecules?
One example is an enzyme changing shape when it comes into contact with a reactant
How does protein shape change as a result of covalent modification?
addition of a chemical group, such as a phosphate, to an amino acid
What can proteins do after denaturation or being newly made and unfolded?
Proteins can bind to the wrong molecules
What are chaperones?
Chaperones are proteins that prevent denatured or newly formed and still unfolded proteins from binding to the wrong molecules
How do chaperones function?
Chaperones, such as heat shock proteins, surround a denatured protein and allow it to refold
