A1.1.1 WATER & MEDIUM OF LIFE

Question 1

What is the significance of water within the environment/in general?

Answer 1

• Life first developed in H2O
• Life depends on H2O to exist
• Exists in 3 states (liquid water, water vapour & ice)
• Provides medium for marine org.

Question 2

It’s significance in a molecular setting?

Answer 2

• A polar molecule (dipole); allows attraction with other polar molecules
• Excellent solvent for chemical reactions
• Link between biotic & abiotic molecules

Question 3

Its significance within living organisms

Answer 3

• Chemical cell comms. do not work outside of H2O
• Water is a metabolite
  → photosynthesis: reactant
  → respiration/digestion: product
• Helpful for enzyme activities

Question 3

Adv. of water

Answer 3

• High buoyancy
• Stable thermal properties

Question 3

How was Earth originally?

Answer 3

A ball of molten mass, unable to sustain life on earth

Question 4

Disadv. of water

Answer 4

• Viscosity > air
• Marine organisms have to adapt their body shape & propulsion mechanisms

Question 4

Imp. of water in cells

Answer 4

• Cells require a complex series of biochemical reactions
  → a solvent is required for reactions (H2O is an excellent solvent)
• The first cells learned to separate ocean H2O w/ cytoplasm (membrane)

Question 4

Water as a solvent:

Answer 4

• Makes up 80% of the fluid in the cytoplasm
  → cytoplasm is clear & colourless
• Makes up the fluid of all organelles
• Permits transport of substances ⇄ of cells

Question 4

Methodology Question: Why do measurements in nature change over time? (i.e. above/below sea levels, etc.)

Answer 4

• Depending on how recent the data was collected, it will change:
  → the methodology used to collect data
  → sometimes natural causes