Chemical and physiological reactions

Inorganic • Carbohydrates, fats, proteins, and nucleic acids
(DNA)
• Contain carbon, are usually large, and are
covalently bonded
• Both equally essential for life

*all chemicals are inorganic or organic and are equally essential for life

Do not contain carbon

Water, salts, and many acids and bases

Organic

• Carbohydrates, fats, proteins, and nucleic acids
(DNA)
• Contain carbon, are usually large, and are
covalently bonded

Water - Inorganic

Most abundant, accounts for 60%-70% of living cells

Most important because of its properties such as, high heat capacity, high heat of vaporization, polar solvent properties, reactivity, and cushioning.

High heat capacity (water)

– Ability to absorb and release heat with little temperature change
– Prevents sudden changes in temperature (water in our body)

High heat of vaporization (water)

– Evaporation requires large amounts of heat
– Useful cooling mechanism

Polar solvent properties (water)

– Dissolves and dissociates ionic substances
– Body’s major transport medium

*polar solvent is liquid with uneven electrical charges, positive side and negative side

Reactivity and cushioning (water)

Reactivity: necessary part of hydrolysis and dehydration synthesis

*Dehydration synthesis builds big molecules from small pieces by taking out water. Hydrolysis does the exact opposite: it breaks big molecules apart by adding water

Cushioning: protects organs from trauma ex. cerebrospinal fluid cushions nervous system organs

Solutions

Mixture of water and other molecules

Solvent

The greatest amount of substance (water)

Solutes

substance present in small amounts dissolved in solvent/water, for example in blood sugar glucose is solute and blood/plasma is solvent

Inorganic (salt)

Salts are ionic compounds that dissociate into separate
ions in water

Ions

called electrolytes because they can conduct electrical currents in solution

Ions play specialized roles in body functions - sodium, potassium, calcium, and iron

Ionic balance is needed for homeostasis

Common salts in body are NaCl, CaCO3, KCl calcium phosphates

Acids

electrolytes, ionize and dissociate in water.

proton donors: they release hydrogen ions (H+)

Important acids: HCl (hydrochloric acid), Stomach acidHCL H Cl+ −

Bases

electrolytes, ionize and dissociate in water.
Are proton acceptors: they pick up H+ ions in solution

NaOH Na OH+ −

When a base dissolves in solution, it releases a
hydroxyl ion (OH –)

important bases are Bicarbonate ion (HCO3–), neutralize stomach acid

pH

Measurement of concentration of Hydrogen Ions Bicarbonate ions [H+] in a solution

More hydrogen ions, the more acidic making pH

More basic higher the pH

pH is negative logarithm of [H+] in moles per liter that
ranges from 0–14

pH scale is logarithmic (exponential), so each pH unit represents a 10-
fold difference. ex. a pH five solution is ten times more than a pH six solutions

Acidic Solution

High pH [H+] but low pH

• pH range is 0–6.99
• Orange juice ~4

Neutral solutions

equal numbers of H+ and OH– ions

• All neutral solutions are pH 7 (pure water) or
7.5

exact best pH is 7.45

Alkanline (basic)

low [H+] but high pH

Alkaline pH is 7.01 - 14

Neutratlization

Acids and bases are mixed together, displacement reactions occur, forming water and salt

NaOH HCl NaCl H O

CPR pH range

Narrow range from 7.45 to 7.45

Arterial pH 7.0 predicts poor outcome, patience with arterial pH less than 6.85 rarely survive.

Buffers

Solutions that resist abrupt and large swings in pH, will release hydrogen ions if pH fails, can bind hydrogen ions if pH falls.

More functions of buffers

convert strong acids or bases that dissociate 100% in water in weak ones weak ones that don’t dissociate

Carbonic acid–bicarbonate system (important buffer system
of blood), respiratory system, urinary system and blood