Module 3 - Water as Biochemical Solvent

WATER

principal component of most cells

104.3°

Water is a bent molecule with a bond angle of

POLAR BONDS

difference in electronegativity between oxygen and hydrogen gives rise to a partial positive and negative charge, usually pictured as δ+ and δ−

DIPOLE

Bonds with positive and negative ends are called

• Ionic Bonds

• Salt Bridges

• Ion-Dipole Interactions

• Dipole-Dipole Interactions

Solvent Properties of Water:

IONIC BONDS & COVALENT BONDS

are the strongest bonds

IONIC BONDS

it is a type of linkage formed from the electrostatic attraction between oppositely charged ions in a chemical compound

SALT BRIDGES

biomolecules often have ionizable groups on them

ION-DIPOLE INTERACTIONS

ion in solution can also interact with molecules that have dipoles

DIPOLE-DIPOLE INTERACTIONS

these forces occur between molecules that are dipoles, with the partial positive side of one molecule attracting the negative side of another molecule

BUFFER

something that resists change

BUFFER SOLUTION

tends to resist change in pH when small to moderate amounts of a strong acid or strong base are added

BUFFER SOLUTION

consists of a mixture of a weak acid and its salt or a weak base and its salt

MAINTENANCE OF THE BLOOD OF pH

important for the proper functioning of our body and can be critical if not maintained

• Bicarbonate

• Hemoglobin

• Plasma Protein

• Phosphates

Main Buffers in Blood:

• Carbonic acid (H2CO3)

• Bicarbonate ion (HCO3-)

Mainly, the buffer involves:

CARBONIC ACID

known as weak acid

BICARBONATE ION

known as the conjugate base

CARBONIC ACID-BICARBONATE BUFFER

the most important buffer for maintaining the pH homeostasis of blood

RESPIRATORY TRACT

can adjust the blood pH upward in minutes by exhaling CO2 from the body

RENAL SYSTEM

can also adjust blood pH through the excretion of hydrogen ions (H+) and the conservation of bicarbonate, but this process takes hours to days to have an effect

KIDNEY

help control acid-base balance by excreting hydrogen ions and generating bicarbonate that helps maintain blood plasma pH within a normal range

PROTEINS

made up of amino acids

PROTEINS

contain positively charged amino groups and negatively charged carboxyl groups

HEMOGLOBIN AS A BUFFER

principal protein inside of red blood cells and accounts for one-third of the mass of the cell

HEMOGLOBIN AS A BUFFER

This buffering helps maintain normal pH

BICARBONATE

regulated in the blood by sodium, as are the phosphate ions

BICARBONATE IONS & CARBONIC ACID

present in the blood in a 20:1 ratio if the blood pH is within the normal range.

BICARBONATE-CARBONIC ACID BUFFER

useful because most of the body’s metabolic wastes, such as lactic acid and ketones, are acids

CARBONIC ACID

evels in the blood are controlled by the expiration of CO2 through the lungs

CARBONIC ANHYDRASE

forces the dissociation of the acid, rendering the blood less acidic

BICARBONATE BUFFER

the primary buffering system of the IF surrounding the cells in tissues throughout the body

CO₂ + H₂O ↔ H₂CO₃ ↔ H⁺ + HCO₃^-

BICARBONATE-CARBONIC ACID BUFFER CHEMICAL FORMULA:

RESPIRATORY SYSTEM

contributes to the balance of acids and bases in the body by regulating the blood levels of carbonic acid

CARBONIC ACID

CO2 in the blood readily reacts with water to form _______

CO2 BLOOD LEVEL RISE

the excess CO2 reacts with water to form additional carbonic acid, lowering blood pH

LOSS OF CO2

reduces blood levels of carbonic acid and thereby adjusts the pH upward, toward normal levels

ACID ENTERS THE BLOODSTREAM

to prevent the blood from becoming acidic

BASE ENTERS THE BLOODSTREAM

to prevent the blood from becoming basic

pH GOES LOWER THAN 6.8/ HIGHER THAN 7.4

enzymes and cells would denature and stop functioning which would cause death.

ACIDOSIS

an abnormal condition due to excess of acid in blood that cause the pH to drop below 7.35

ALKALOSIS

an abnormal condition due to excess of base in blood that cause the pH to rise above 7.45

INTRAVENOUS HCO^3-

treatment given to people who have dangerously low blood pH