Lab 9 - Acid Base Balance (new) (in progess)

Balance of substances contributing to homeostasis

Acid-base balance

Found in the stomach, blood, extracellular fluids, cytosol, and urine

Acids and bases

The cells of which system release acids and bases?

Immune system

A hydrogen ion (H+) donor

Acid

A hydroxyl ion (OH-) donor

Base

Negatively charged ions that combine with hydrogen ions in a solution

Alkali (bases)

Measure of the acidity or alkalinity of a solution

pH

Equal to the negative logarithm of the hydrogen ion concentration

pH

A combination of two or more chemicals that minimize the pH change of a solution when a strong acid or base has been added

Buffer system

What two chemicals typically comprise a buffer system?

Weak acid and it’s salt

pH scale range

0-14

pH related to greater hydrogen ion concentration

Lower, acidic

pH related to lower hydrogen ion concentration

Higher, basic

pH indicating neutrality

7

When the number of hydrogen ions = hydroxyl ions

Neutrality (pH 7)

Neutral pH

7

A shift of how many pH units represents a tenfold increase or decrease in hydrogen ion concentration

One pH

A solution of pH 4 has how many times more hydrogen ions as a pH 5?

10x

What is the pH of water?

~7

What macromolecule primarily makes up albumin (egg white)?

Protein

What do proteins change when exposed to different pH or temperature?

Shape

Why does the body strictly regulate pH and temperature?

To prevent protein and enzyme denaturing

Can all proteins refold after denaturing? Can any?

Not all, only some can

Required by almost all biochemical reactions

Enzymes

Work optimally within relatively narrow temperature and pH ranges

Enzymes

How does acid affect the protein in egg white?

Denatures the protein, leading to unfolding and coagulation (white and solid clumps)

How does acid affect protein structure

Acid denatures protein

What would an acidic environment do to the body

It would disrupt necessary enzyme dependent biochemical reactions

Compound resisting pH change

Buffer

What does the buffer do with hydrogen ions (H+) when pH is falling (acidic)

Takes up hydrogen ions (H+) from the solution

What does the buffer do with hydrogen ions (H+) when pH is rising (basic)

Donates hydrogen ions (H+) to the solution

Protein function, and therefore cellular function is dependent on what levels

pH

Category of proteins that catalyze chemical reactions and are required for cell survival

Enzymes

What part of a protein is disrupted due to low or high pH

Three-dimensional structure

What conditions aside from pH impact three dimensional enzyme structure?

Heat and high salt concentration

Loss of the three dimensional structure of a protein

Denaturation

H₂CO₃ < > H⁺+ HCO₃^-

Bicarbonate buffer system

H₂PO₄^{- < >} H⁺+ HPO₄^2-

Phosphate buffering system

Which buffer system is this

Protein buffering system

If a solution is rising in pH, does it have more or less protein buffering molecules

Less, because it has already released hydrogen molecules to buffer the rise in pH

If a solution is rising in pH, will it need to produce hydrogen ions or take them up

Take them up

Consider the bicarbonate buffer system. If pH is rising, will carbonic acid (H2CO3) form or dissociate

Dissociate

Consider the bicarbonate buffer system. If pH is falling, will carbonic acid (H2CO3) form or dissociate

Form

Consider the phosphate buffering system. What will favour the formation of dihydrogen phosphate (H2PO4-)

Falling pH

Consider the phosphate buffering system. What will favour the dissociation of dihydrogen phosphate (H2PO4-)

Rise in pH

What part of the protein buffering system is the most acidic?

The carboxyl group (-COOH)

Consider the protein buffering system. Will a rise in pH favour the equation moving to the right or the left?

Shift to the right, favoring the dissociation of H+ ions

Consider the protein buffering system. Will a drop in pH favour the equation moving to the right or the left?

Left

What is produced when carbon dioxide and water combine

Carbonic acid

Why does carbonic acid lower blood pH

It is acidic and therefore a source of hydrogen ions

Is it possible to lower the amount of water in the blood sufficiently to prevent the formation of carbonic acid? Why or why not?

No, it would lead to fatal dehydration

What does the body have to eliminate to prevent carbonic acid formation

C02

What organ does the body use to eliminate CO₂

The lungs

The removal of excess base in the blood left over from stomach acid production

Alkaline

What fluid becomes alkaline a base is removed from the blood

Plasma/serum

What organ helps the lungs with blood pH

Kidneys

Carbonic acid, dihydrogen phosphate, and proteins are always present in the blood. Based on this, would you expect the chemical buffering systems to act in seconds, minutes, or hours

Seconds

Why do chemical buffering systems act in seconds

The molecules they rely on are already in the blood

Which physiological buffering system is faster, respiratory or renal? Why?

Respiratory system, greater surface area

Which two ions absorbed and secreted by the kidneys work to regulate pH

Bicarbonate and hydrogen ions

Does bicarbonate reabsorption via kidney tubules increase or decrease blood pH

Increases (alkaline)

Does bicarbonate excretion via kidney tubules increase or decrease blood pH

Decreases (acidic)

Which two body systems work together to maintain blood pH

Respiratory and renal