1.1 Chemical Elements & Biological Compounds

Question 1

Inorganic Ions

Answer 1

• living organisms need a variety of inorganic ions to survive used in muscle contraction and maintaining water in cells
• two groups - macronutrients and micronutrients
For example Copper & Zinc

Question 2

Magnesium Macronutrients

Answer 2

Important constituent of chlorophyll and is essential for photosynthesis
Plants without Mg in there soil cannot make chlorophyll, so leaves turn yellow (chlorosis) - growth is stunted (no glucose)

Question 3

Iron Macronutrients

Answer 3

Constituent of Haemoglobin, which transports oxygen in red blood cells
Lack of iron in human diet can lead to anaemia

Question 4

Phosphate Ions Macronutrients

Answer 4

Used for making nucleotides including ATP and are a constituent of phospholipids found in biological membranes

Question 5

Calcium Macronutrients

Answer 5

Like phosphate is an important structural component of bones and teeth in mammals and is a component of plant cell walls providing strength

Question 6

Dipole

Answer 6

Polar molecule with a positive and negative charge, separated by a small distance

Question 7

Hydrogen Bonds

Answer 7

The weak attraction force between the partial positive charge of a hydrogen atom of one molecule and partial negative charge on another atom, usually oxygen or nitrogen

Question 8

Water Molecule

Answer 8

• a medium of metabolic acids and an important constituent of cells
• a dipole meaning it has a positively charged end (hydrogen) and a negatively charged end (oxygen) no overall charge
• it’s a polar molecule meaning they have delta charges
• hydrogen bonds form between delta charges on oxygen and hydrogen
• hydrogen bonds are weak, large number present in water makes the molecule difficult to separate giving water a wide range of physical properties

Question 9

Water Properties: Solvent

Answer 9

Living organisms obtain their key element from aqueous solution, water is such a good solvent it’s called a universal solvent, dipoles attract charged particles
• dissolve in water, chemical reactions happen
• transport medium (animals, plasma transports and transporting xylem)
• non-polar molecules (lipids) don’t dissolve

Question 10

Water Properties: Metabolite

Answer 10

Water is used in many biochemical reactions as a reactant
• CO2 produces glucose in photosynthesis
• Hydrolysis - breaking down of large molecules into smaller molecules, addition to water molecules
Maltose + Water = glucose + glucose
• condensation reaction - chemical process in which two molecules combine to form a more complex molecule elimination of a molecule of water

Question 11

Water Properties: High Specific Heat Capacity

Answer 11

Energy required to raise the temperature of 1g of a substance through 1 degree Celsius
Large amount of heat energy is needed to raise its temp
• H bonds between water molecules restricting their movement, resisting an increase in Kinetic energy, increase in temp
• allows enzymes to work efficiently
• prevents large fluctuations in water temp which is important in keeping aquatic habitats stable

Question 12

Water Properties: High latent heat of vaporisation

Answer 12

Energy required to convert 1g of a liquid into a vapour at the same temperature
• a lot of heat energy is needed to change it from liquid to vapour
• key in temperature control where heat is used to vaporise water from sweat on the skin, water evaporates the body cools

Question 13

Water Properties: Cohesion

Answer 13

Attraction of water molecules for each other, because of the dipole structure of water producing H bonds
• water molecules attract each other forming H bonds. Individually weak but because there are many of them, molecules stick together in a lattice
• allows columns of water to be drawn up xylem vessels in plants

Question 14

Water Properties: High Surface Tension

Answer 14

Cohesion between water molecules at the surface produce surface tension, at ordinary temps water has highest surface tension of any fluid except mercury
In a pond, cohesion in water molecules at the surface produce surface tension so insects (pond skaters) is supported by

Question 15

Water Properties: High Density

Answer 15

Denser than air, provides habitat for aquatic organisms, provide support + buoyancy
• max density is 4 degrees
• ice is less dense than liquid water, H bonds hold molecules further apart than they are in liquid ice floats
• ice is a good insulator, prevents large bodies of water losing heat + freezing completely - organisms beneath survive

Question 16

Water Properties: Transparent

Answer 16

Water is transparent, allowing light to pass through. Allowing aquatic plants to photosynthesise effectively