most needed element making up 3.3% of the organisms and the other
elements named make up part of the 8% of trace elements.
2.1.3 1 State one role for each of the elements mentioned in 2.1.2.
Nitrogen is responsible for the synthesis of proteins from amino acids, and
synthesis of coenzymes. Phosphorus is responsible for the synthesis of
nucleic acids ATP and built into bone. Sulfer is responsible for the
synthesis of proteins. Calcium is responsible for middle lamella formation
between plant cells, a constituent of bone, used for muscle contraction and
for impulse transmissions across synapse, and blood clotting. Iron is
responsible because it is a constituent of hemoglobin and helps red blood
cells gets oxygen.
Topic: 2 – Chemistry of Life
Sub-topic: 2.1 – Chemicals Elements and Water
Page: 2
2.1.4 2 Outline the difference between an atom and an ion.
An atom is the smallest unit of matter that still retains the properties of an
element. While an ion is an atom that has gained or lost electrons, thus
acquiring a charge making it an ion instead of an atom.
2.1.5 2 Outline the properties of water that are significant to living organisms
including transparency, cohesion, solvent, properties, and thermal properties.
Properties of Water
Topic: 2 – Chemistry of Life
Sub-topic: 2.1 – Chemicals Elements and Water
Page: 3
2.1.6 3 Explain the significance to organisms of water as a coolant, transport
medium and habitat, in terms of its properties.
Water is significant as a coolant because water has such a high heat of
vaporization which is the quantity of heat a liquid must absorb for 1 gram
of it be converted from the liquid to the gaseous state. Waters high heat of
vaporization helps moderate Earth’s climate. As a liquid evaporates, the
surface of the liquid that remains behind cools down. The evaporative
cooling occurs because the hottest molecules, those with the greatest
kinetic energy, are the most likely to leave as a gas. Evaporative cooling
of water contributes to the stability of temperature in lakes and ponds and
also provides a mechanism that prevents terrestrial organism from
overheating. Water is also significant as a transport medium because of
evaporation from leaves pulls water upward from the roots. Cohesion due
to hydrogen bonding helps hold together the column of water within a
vessel. Adhesion of the water to the vessel wall also helps in resisting the
downward pull of gravity. Water also is a used as a transport in organisms
because is used to transport materials through the blood and water is what
makes the blood run. Water also helps in habitats of the environment by
freezing water on the top layer insulating the organisms inside. And also
certain animals use water as a surface tension to move over water.