Proteins - structure Flashcards
(17 cards)
What factors are proteins sensitive to that can affect their structure?
Temperature and pH changes
Proteins are sensitive to environmental changes, particularly temperature and pH, which can disrupt their structure.
What is the dependence of a protein’s precise structure?
Ionic interactions, hydrogen bonds, and other intermolecular forces between polypeptide chains
The precise structure of a protein is reliant on these interactions being intact.
What is denaturation in the context of proteins?
The irreversible change of protein conformation
Denaturation results in a permanent alteration in the protein’s structure.
How do temperature and pH extremes lead to denaturation?
They interfere with the bonds that maintain protein structure
Denaturation occurs when the bonds between R groups are disrupted.
What type of bonds are broken during denaturation?
Weak bonds between different R groups
These bonds are weaker compared to peptide bonds that hold amino acids together.
What can the altered shape of a protein affect?
Its function, physical state, and general usefulness
A protein’s altered shape due to denaturation can significantly impact its role.
What is considered an optimum pH for a protein?
A pH at which the protein’s 3D structure is not denatured
Proteins have specific pH levels where they maintain their structure.
Is denaturation reversible?
Almost always irreversible
Proteins cannot typically return to their original conformation after denaturation.
What small changes can some proteins undergo in response to pH fluctuations?
Small denaturations and renaturations
Some proteins can adapt to minor changes in pH.
What is an example of a protein that can undergo small denaturations?
Haemoglobin
Haemoglobin can respond to small fluctuations in pH.
How can denaturation be observed in cooking?
By changes in egg white when fried or poached
The protein albumin in egg whites undergoes denaturation with heat.
What happens to the hydrophobic amino acids in albumin during cooking?
They move to the edges, causing the protein to become insoluble
This leads to the formation of a solid layer in the cooked egg white.
What is the optimum pH of the enzyme pepsin?
pH 2
Pepsin functions optimally in the acidic environment of the stomach.
What type of organisms have evolved proteins that are stable at extreme conditions?
Extremophiles
These organisms can survive at extreme pH or temperature levels.
What is the significance of Thermus aquaticus?
It is a bacterium that lives in hot springs at 80°C
This temperature would denature most other proteins.
How can denaturation of enzymes be used in experiments?
To measure enzyme activity
Experiments can establish the optimum pH or temperature for enzymes.
Why can’t many protein-based drugs be administered orally?
They will be denatured by stomach acid
These drugs require alternative delivery methods, such as injection.
