Acid, basic and buffer Flashcards
Describe the role of water in biological systems.
Water acts as a solvent inside and outside the cell, facilitating biochemical reactions and the transport of substances.
Define pH and its significance in biological fluids.
pH is a measure of the concentration of hydrogen ions (H+) in a solution, indicating its acidity or basicity, which is crucial for the proper functioning of cellular structures.
How is pH calculated from hydrogen ion concentration?
pH is calculated using the formula pH = -log
What is the pH of pure water and why is it considered neutral?
The pH of pure water is 7, which is considered neutral because it has equal concentrations of hydrogen ions [H+] and hydroxide ions [OH-].
Explain the implications of pH changes in biological systems.
Changes in pH to more acidic (pH < 7) or more basic (pH > 7) conditions can disrupt protein shape and function, affecting cellular processes.
Identify the characteristics of acidic and basic solutions based on pH.
Acidic solutions have a pH < 7 (high [H+]), while basic solutions have a pH > 7 (low [H+]).
What is the importance of maintaining pH within a specific range in cells?
Maintaining pH around 7 is essential for the proper functioning of proteins, which play critical roles as enzymes, transporters, and receptors.
Define acids and provide an example.
An acid is any molecule, ion, or chemical group that tends to release H+. An example of an acid is hydrochloric acid (HCl) or a carboxyl group (-COOH).
Define bases and provide an example.
A base is any ion, molecule, or chemical group that accepts H+. Examples of bases include hydroxide ions (OH-), ammonia (NH3), and amino groups (NH2).
What happens to pH when an acid is added to a solution?
When an acid is added to a solution, the concentration of H+ increases, causing the pH to decrease.
What happens to pH when a base is added to a solution?
When a base is added to a solution, the concentration of H+ decreases, resulting in an increase in pH.
Define the dissociation constant for weak acids and bases.
The dissociation constant (Ka) for weak acids and bases is less than 1, indicating that they are mainly undissociated at equilibrium.
How is the pH of a strong basic solution calculated?
The pH of a strong basic solution can be calculated using the concentration of hydroxide ions (OH-).
Explain the significance of the Ka value for HCl.
A Ka value greater than 1 indicates that HCl is mostly dissociated in solution, leading to a low concentration of undissociated HCl.
What is a buffer solution?
A buffer solution minimizes changes in pH when small amounts of strong acid or strong base are added, typically made by mixing a weak acid and its conjugate base.
How does a buffer maintain pH when acids are added?
When acids are added, the H+ ions react with the conjugate base in the buffer, preventing significant changes in pH.
What happens to pH when bases are added to a buffer solution?
When bases are added, the OH- ions react with H+ from the weak acid in the buffer, forming water and maintaining the pH.
Describe the Henderson-Hasselbalch equation.
The Henderson-Hasselbalch equation is pH = pKa + log10[A-]/[HA], used to calculate the pH of a buffer solution.
What is the significance of pKa in a buffer solution?
The pKa is the pH at which the concentrations of the acid (HA) and its conjugate base (A-) are equal, providing maximal buffering capacity.
Describe the effective pH range of Acetate/CH3COOH buffer.
The effective pH range of Acetate/CH3COOH buffer is 4.76, with a range of 3.6-5.6.
Define the pKa and its significance in buffer selection.
The pKa is the negative logarithm of the acid dissociation constant, and it is significant in buffer selection because a buffer should be chosen whose pKa is close to the desired pH.
How is TRIS buffer prepared using TRIS base and HCl?
TRIS buffer is prepared by dissolving the TRIS base in water and then adjusting the pH with HCl, generating the acid form of TRIS.
Explain the process of preparing TRIS buffer using TRIS hydrochloride.
TRIS buffer can be prepared by combining TRIS base and TRIS hydrochloride in the appropriate ratio.
What is the role of intracellular and extracellular buffer systems in the human body?
The role of intracellular and extracellular buffer systems is to maintain hydrogen ion homeostasis and keep the pH around 7, which is essential for proper cellular function.
