3.1 Chemistry of Life
Natalie Nam
3.1.1 STATE THAT THE MOST FREQUENTLY OCCURRING CHEMICAL ELEMENTS IN LIVING THINGS ARE
CARBON, HYDROGEN AND NITROGEN
Living organism are made up of 4 main elements:
- Carbon
- Hydrogen
- Oxygen
- Nitrogen
3.1.2 STATE THAT A VARIETY OF OTHER ELEMENTS ARE NEEDED BY LIVING ORGANISMS, INCLUDING
SULFUR, CALCIUM, PHOSPHORUS, IRON AND SODIUM
Living organisms need 4 elements:
-
sulfur
Calcium
Phosphorus
Iron
Sodium
3.1.3. STATE ONE ROLE FOR EACH OF THE ELEMENTS MENTIONED 3.1.2
Elements
Sulfur
Iron
Phosphorus
Calcium
Sodium
Use
Essential in variable group of two amino
acids : Cysteine and methionine
Essential in mitochondrial electron
transport cytochrome protein
Essential in phospholipids and in
nucleotides (DNA, RNA, ATP)
Essential in animal bones, teeth
Plants: Essential role in osmotic balance
Animals: Essential in neuron membrane
potential and involved in the generation of
nerve impulses in neurons.
3.1.4 DRAW AND LABEL A DIAGRAM SHOWING THE STRUCTURE OF WATER MOLECULES TO SHOW
THEIR POLARITY AND HYDROGEN BOND FORMATION
Diagram 3.1.4 Showing the structure of water molecules
3.1 Chemistry of Life
Natalie Nam
Structure of water molecule:
- Made up of two H2 atoms and a single O2 atom held together by a polar covalent
bond.
Polar Covalent bond:
- Electrons are not shared equally  O2 has more protons hence will attract
electrons more strongly. Therefore, the O2 atoms will be more negative (δ-) and
H2 more positive (δ+).
Diagram 3.1.4 Showing hydrogen bond formation
Hydrogen Bond formation
- Since Oxygen atom is (δ+) and Hydrogen atoms are (δ+), these opposite charges
attract each other hence forming hydrogen bonds.
- These hydrogen bonds are weak and can be easily broken.
3.1.5 OUTLINE THE THERMAL, COHESIVE AND SOLVENT PROPERTIES OF WATER
Thermal
Hydrogen bonds between the polar water molecules cause water to resist changes:
- High Specific heat – a high enery needed to change water temperature by one
degree celcius
- High heat of fusion – a high amount of energy will be lost to freeze water
Cohesive
Water molecules ‘stick together’ due to hydrogen bonds  so water has a high cohesion
Solvent
- The polarity of water attracts or dissolve any other polar or charged particle
3.1.6 EXPLAIN THE RELATIONSHIP BETWEEN THE PROPERTIES OF WATER AND ITS USES IN LIVING
ORGANISMS AS A COOLANT, MEDIUM FOR METABOLIC REACTIONS AND TRANSPORT MEDIUM
Coolant
Metabolic Reactions
3.1 Chemistry of Life
Natalie Nam
Water is a polar medium where other polar or charged molecules can dissolve in
Transport
Hydrogen bonds between water molecules allow them to be cohesive. Therefore water
is able to by pulled up in xylem vessels.