Water Flashcards
What is water?
Water is a major component of cells and makes up 60-70% of the human body.
What is the importance of water?
3
Water is one of the most useful molecules for life. Its uses include:
- As a reactant in cells (e.g. photosynthesis, hydrolysis).
- Provides structural support in cells.
- Keeps organisms cool to maintain an optimum body temperature.
What are the 4/5 special properties of water?
- Metabolic importance / solvent for chemical reactions
- High heat capacity.
- Heat of vaporization.
- Cohesive properties.
Describe the structure of water?
Water molecules (H2O) are made from:
1 O atom
2 H atoms.
Why is water a polar molecule?
- O is more electronegative than H
- so attracts the electron density in the covalent bonds more strongly.
Forms O s- & H s+
Explain the role of hydrogen ions in the body
- High concentration of H+ = low (acidic pH)
- H+ ions interact with the tertiary structure of proteins. ( Specifically H- bond & ionic bonds) which can causes proteins to denature
Describe the metabolic importance of water?
Metabolic reactions such as condensation and hydrolysis which are used in forming and breaking of chemical bonds
Describe why water is useful as a solvent?
By allowing gases to readily diffuse as well as enzymes and waste products e.g. ammonia and urea.
Describe why the high specific heat capacity of
why is this useful?
This is water molecules stick together with hydrogen bonds meaning that a lot of energy is required to break these bonds. This helps to minimise temperature fluctuations in living things therefore it acts as a buffer.
Describe the strong cohesion in water in xylems (A-A*)
enables what?
what does this support?
as a result what is high?
The strong cohesion between molecules enables effective transport of water in tube-like xylem. The strong cohesion supports columns of water, as a result of strong cohesion the surface tension at the water-air boundary is high.
What is the attraction between water molecules?
Hydrogen bonding
Which of the following bodily process would most likely be hindered by a lack of water in the body? (A-A*)
Digestion
Define water’s property of cohesion. (A-A*)
The intermolecular forces between water molecules
Why does ice float on water? (A-A*)
structure
The lattice structure of ice created through h bonding makes ice less dense and then the freely flowing molecules of liquid water
Why does ice float on water?
The lattice structure of the ice created through hydrogen bonding makes ice less dense than the freely flowing molecules of liquid water
