Amino Acids as Buffers in the Cardiovascular System

Flashcards covering key concepts from the lecture on amino acids as buffers within the cardiovascular system.

What is a buffer system?

A chemical equilibrium system that resists change in pH when acids or bases are added.

What do weak acids and bases do in buffer systems?

They usually contain equal quantities of a weak acid and its conjugate base.

What is the formula for the ion product of water (Kw)?

Kw = [H3O+][OH-] = 1 x 10^{-14}

What is the relationship between Ka and Kb for conjugate acid-base pairs?

Ka x Kb = Kw.

How is pH calculated?

pH = - log_{10} [H3O+].

What is the formula to find pKa?

pKa = - log Ka.

What does the Henderson-Hasselbalch equation represent?

It expresses the relationship between pH, pKa, and the ratio of concentrations of the conjugate base and acid.

What charge does an amino acid have at low pH?

It is completely protonated and typically positively charged.

What happens to an amino acid at high pH?

It becomes completely deprotonated and typically negatively charged.

What is a zwitterion?

A molecule with positive and negative charges that balance out, resulting in a neutral charge overall.

What does amphoteric mean in the context of amino acids?

Amino acids can act as both acids and bases.

What is the titration curve for a weak acid vs strong base?

The pH increases gradually and exhibits a more pronounced change at the equivalence point.

What species can exist in an amino acid's titration curve?

Different protonation states of the amino acid depending on pH.

What does the term 'half-neutralization' refer to in titrations?

It is when half the acid is neutralized and pH equals pKa.

What is the significance of a pKa value?

It indicates the pH at which a weak acid is half dissociated.

What pH indicates a fully deprotonated amino acid?

A high pH.

What role does the side chain of histidine play in buffering?

It can accept or donate protons depending on pH.

How does hemoglobin act as a buffer?

It can bind and release protons and carbon dioxide to resist pH changes.

What is the importance of pH in biological systems?

pH influences enzyme activity and metabolic processes.

What is the physiological pH of blood?

Approximately 7.35 to 7.45.

What does acidosis refer to?

A condition where blood pH drops below 7.35.

What is alkalosis?

A condition where blood pH rises above 7.45.

What type of reaction does amphoterism enable in amino acids?

Reactions with both acids and bases.

How can the pH of salt solutions be calculated?

Using hydrolysis reactions of the salt's ions.

What is the relationship between pH and pOH?

pH + pOH = 14.

What determines the buffer capacity of a solution?

The concentration of the buffer components (acid and conjugate base).

Why are amino acids essential for buffering in blood?

They can react with both excess acids and bases to maintain pH.

What is the formula for pOH?

pOH = - log_{10} [OH-].

At which pH does imidazole act as a proton acceptor?

At pH < 6.0.

What happens at the equivalence point of a titration involving a weak acid?

The solution becomes more basic due to the formation of the conjugate base.

What is a common amino acid example in buffer systems?

Glycine.

What is the charge status of amino acids at physiological pH?

They typically exist as zwitterions.

What can affect the buffering capacity of a solution?

The amount of acidic and basic components present.

How is the equivalence point identified in a titration curve?

By the steepest incline in pH change.

What does the titration curve help in calculating?

pKa values for ionizable groups of amino acids.

What is the impact of temperature on pH?

Temperature fluctuations can alter the ionization of weak acids and bases.

What is the dissociation constant for a weak acid called?

Ka.

What can weak bases form in solutions?

Conjugate acids when they accept protons.

How does the concentration of H2PO4- relate to pH?

It influences the ability to maintain the desired pH in a phosphate buffer.

What is the main function of buffers in biological systems?

To maintain stable pH levels.

What is the significance of the titration curve shape for amino acids?

It reveals the pKa values and the buffering regions.

How does the structure of an amino acid contribute to its buffering capacity?

The functional groups present allow them to accept or donate protons.

What does complete protonation of amino acids entail?

It is when the amino acid accepts all possible protons, making it positively charged.