biological
Contents:
• Water
• Monomers and Polymers
• Carbohydrates
• Lipids
• Proteins
• Inorganic Ions
• Chemical Tests
, W ater
of
importance water
60-70% human body
reactant in cells
eq) photosynthesis;hydrolysis
provides structural supportin cells
keeps organisms cool to maintain an optimum body temperature
of
properties water
metabolic importance
hydrolysis reaction involves using a water molecule to break a bond
eg) ATP H20 +
ADD +Pi +
energy
condensation reaction involves releasing a water molecule to form a bond
eg) ADP + 4; + ATP H20
energy
+
high heatof vapourisation
latentheat
of vapourisation is the ofenergy needed to
amount change lkg of liquid to gas
water heats up, hydrogen bonding makes itdifficultto separate water molecules from each other, so requires a lot
ofenergy to evaporate
energy used up to evaporate water, which cools environment
29) sweating regulates body temperature
high heatcapacity
specific heatcapacity is the amount of heat lag of a substance absorbs/loses to change temperature by IC
high heatcapacity means water takes a long time to heat
a nd cool
water has a larger specific heatcapacity than sand, which is why land cools faster than sea
water is used by warm blooded animals to more
evenly disperse heat in bodies
good solvent
water is a good a s ions and polar molecules
solvent can easily dissolve in it
water is a polar molecule as positive end of
water attracts negative ions, whilstnegative end of
water attracts positive ions
cohesive properties
cohesion is the strong attraction between water molecules due to hydrogen bonds
produces surface tension where water meets air, resulting in droplets when on a dry surface
plants use cohesion to transport water from roots to leaves
habitat
water is a highly stable environmentthatdoes change
not
easily
water provides a stable habitatfor many species
structure water
of
water molecules (H,0) are made from oxygen atom and 2 hydrogen atoms
polar molecule as oxygen atoms are 5 and hydrogen atoms are st
hydrogen atom on one water molecule attracted to oxygen atom on another water molecule (hydrogen bonding)
5-
8
HH8+
+
8
- H5t
I 5 -
8
H5t
05:
s
H H5+
+