P2. Introduction to Biochemistry and Water

water

the most abundant substance in living systems.

• It makes up 70% or more of the weight of most

organisms.

hydrogen bond

Negative oxygen end of one water molecule is

attracted to the positive hydrogen end of

another water molecule to form a ____________

Cohesion

Adhesion

Water as Solvent

Thermal Properties

PROPERTIES OF WATER:

COHESION

occurs as a result of the

polarity of a water molecule

and its ability to form

hydrogen bonds.

cohesion

Results in surface tension (a

measure of the strength of

water’s surface).

ADHESION

• Attraction between water and other substances.

• Water will make hydrogen bonds with other surfaces such as glass, soil, plant tissues, and cotton.

Capillary action

caused by the combination of adhesive forces causing water to bond to surface.

hydrophilic

All substances that dissolve

in water are _________

including polar molecules

such as glucose, and

particles with positive or

negative charges such as

sodium and chloride ions.

• Substances that water

  adheres to, cellulose for

  example, are also

  _________

hydrophobic

Molecules are __________

if they do not have negative

or positive charges and are

nonpolar.

propanone (acetone)

Hydrophobic molecules dissolve in other solvents such as ______________

95%

Blood plasma consists of mainly of water

plus dissolved substances which it transports.

Glucose

a polar molecule hence freely soluble;

carried by the blood plasma

Amino acids

positive and negative charges (due to the amine and acid groups) therefore soluble in

water; carried by the blood plasma. R group varies, can be polar, non-polar or charged

Oxygen

– a non-polar molecule; due to its small

size, it is soluble in water. At higher

temperature, the solubility of _______

decreases.

Hemoglobin

___________in red blood cells carry the majority of oxygen

4.2

vaporization
fusion

• Water has a high specific heat capacity (_____Joules is required to raise the temperature of 1 g of water by 1°C).

• Water has a high heat of ________ (amount of energy needed to change from a liquid to a gas or vapor).

• Water has a high heat of ______(amount of energy needed to be lost to change liquid water to ice).

water as coolant

• High temperatures damage tissues and denature proteins – causing enzymes to cease to work.

• It takes a lot of energy for water to change temperature, which means that it will heat and cool slowly than air or land.