Water Flashcards
What are some important functions of water?
- It is a metabolite in many important metabolic reactions.
- It is a solvent, most metabolic reactions take place in a solution.
- Aids in temperature control, because it has a high latent heat of vaporisation, and a high specific heat capacity
- Molecules of water are very cohesive, which helps water transport in organisms.
What is the structure of water molecules?
• Two atoms of hydrogen, One Atom Of Oxygen.
What is the charge of water?
Slight Positive Charge.
Why does water have a slight positive charge?
- Shared Negative Electrons are pulled towards the Oxygen Atom, the other side of the hydrogen atom is left with a slight positive charge.
- Having both negative and positive poles makes the water di-polar.
Why does water have a high boiling point?
- Water molecules are very cohesive, they stick together.
- This means it takes more energy to separate them than would be needed if they did not bond to one another.
- This means the boiling point of water is higher than expected.
Why does water have a high specific heat capacity?
• Due to a greater boiling point than expected, it takes more energy to heat a given mass of water.
Why is having a high specific heat capacity a useful feature for water?
- It acts as a buffer against sudden temperature variations.
- This means aquatic environments can be stable in temperature.
- Also means that, as organisms are mostly water, it buffers them against sudden temperature changes to the environment.
Why does water have a high latent heat of vaporisation?
- Hydrogen bonding between water molecules means that it requires a lot of energy to evaporate 1 g of water.
- This energy is called latent heat of vaporisation
Why is a high latent heat of vaporisation for water beneficial to an organism?
• Means that evaporation of water through sweating in mammals is a very effective means of cooling, as body heat is used to evaporate the water.
What is cohesion?
The tendency of molecules to stick together, water molecules are very cohesive because they are polar.
Why is cohesion of water beneficial to an organism?
- Due to waters large cohesive forces, it allows it to be pulled up through a tube such as the xylem vessel in plants.
- When water molecules meet air they tend to be pulled back into the body of water rather than escaping from it, due to surface tension, allowing it to be strong enough to support small organisms such as pond skaters.
- Strong cohesion means that water has a high surface tension when it comes into contact with air.
How is water utilised in metabolism?
- Water is used to break down many complex molecules via hydrolysis.
- Chemical reactions take place in an aqueous medium.
- Water is an important material in photosynthesis.
What are some important functions of water?
- its evaporation cools organisms and allows them to control their temperature.
- It is not easily compressed, thus provides support.
- It is transparent, allowing aquatic plants to photosynthesise, light rays can penetrate the jelly like like fluid that fills the eye so it can reach the retina.
