35 Questions
What is the primary function of the hydration shell around proteins and other biomolecules?
To make them soluble
What is the role of conserved water molecules in proteins?
To have a structural or functional role
What is the primary factor that determines protein folding?
The interaction of water with the polypeptide backbone and side chains
Which type of macromolecules has a high level of hydration?
Polysaccharides
What is the nature of hydrophobic interactions in proteins?
Entirely water-induced forces
What is the term used to describe the hydrogen-bonded network of water molecules surrounding a protein?
Hydration shell
What role do water molecules often play in biochemical reactions catalyzed by enzymes?
They donate hydrogen atoms and act as nucleophilic reagents
What is the term used to describe the conserved water molecules that play a crucial role in ligand binding to proteins?
Ordered water molecules
What is the primary mechanism by which water molecules influence protein dynamics?
Hydrogen bonding interactions
What is the term used to describe the random movement of molecules in a solvent, such as water?
Diffusion
What is the primary role of water in facilitating biochemical processes?
To facilitate chemical reactions at sufficient rates
Why do biologically important gases like oxygen and carbon dioxide have poor solubility in water?
Because they are non-polar molecules
What is the term for the phenomenon where water separates and shields ions from each other?
Dielectric effect
What is the role of water in the interaction with amphipathic molecules like fatty acids?
Water forms a hydrophobic cage around the non-polar groups
What is the result of water-mediated disruption of hydrogen bonds between polypeptides?
Denaturation of the protein
What is pKa in relation to an acid?
A measure of the strength of the acid
In the Henderson-Hasselbalch equation, what does the term 'pH = pKa + log10 [base]/[acid]' describe?
The relationship between the concentration of the base and acid in a weak acid-base solution
What happens to the pH when a weak acid is at half-neutralization point (when [A-]/[HA] = 1)?
pH equals pKa
When a relatively large amount of hydroxide ions is added to a weak acid, what property of the acid prevents drastic pH changes in the solution?
pKa value
How is the acid dissociation constant (Ka) related to the pKa value of an acid?
Ka = -pKa
What is the primary relationship described by the Henderson-Hasselbalch equation in terms of acid and base concentrations?
Logarithmic relationship
How does the pH of a buffer solution change when the pH equals the pKa value of the weak acid?
pH remains constant
What property does the ratio [A-]/[HA] represent in the context of weak acids?
Ratio of conjugate base to undissociated acid
In a buffer solution, when the pH equals the pKa, what can be said about the concentrations of the acid and its conjugate base?
They are equal
Why is it important to know the numerical value of the acid dissociation constant (pKa) of an acid?
To determine the strength of the acid
What is the effect on the concentration of H+ when the pH of a solution decreases by 4 units?
The concentration of H+ increases by 10,000 times
Why is it important to consider the proton concentration when performing mathematical operations with pH values?
Because pH is a logarithmic scale, and directly performing mathematical operations with pH values can lead to incorrect results
What is the relationship between Ka and pKa for a weak acid?
pKa = -log10(Ka)
What is the role of a buffer in a solution?
A buffer can 'resist' a change in pH
What is the species formed by the reception of a proton?
A conjugate acid
What is the significance of the pH of a solution in relation to the concentration of H+?
A lower pH indicates a higher concentration of H+
How does the concentration of hydroxide ions affect the pH of a solution?
An increase in hydroxide ions decreases the pH of a solution
What is the role of water in acid-base chemistry?
Water can act as both an acid and a base
What is the relationship between the concentration of H+ and the pH of a solution?
pH = -log10[H+]
Why is it important to control the pH inside cells?
To maintain proper cellular function and prevent damage to cellular components
Test your knowledge on the hydrophobic effect phenomenon as described by Nelson & Cox (2005). Explore concepts such as interaction of water with amphipathic molecules, formation of lipid clusters, micelles, and the impact on water entropy.
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