Biological Molecules: Water Flashcards
What are the 5 properties of water?
- Cohesion
- Metabolite
- Solvent
- Latent heat capacity
- High specific heat capacity
What are the 2 uses of water as a metabolite?
- Used in hydrolysis reactions
- Formed in condensation reactions
What is the use of water as a solvent?
Dissolves and transports ions/polar molecules
Give two examples of reactions where water is a metabolite:
Condensation
Hydrolysis
What does it mean if water is a solvent?
Some substances dissolve in it.
How does water help with temperature control?
Has a high latent heat of vapourisation
Has a high specific heat capacity
Why are the sides of hydrogen atoms that are opposite to the shared oxygen atoms slightly positively charged?
The shared negative hydrogen electrons are pulled towards the oxygen atom.
Why is the side of oxygen that is opposite to the shared hydrogen atoms slightly negatively charged?
It has unshared negative electrons.
Water molecules have a slight ____ charge on one side of the atom, and a slight _____ charge on the other side.
Positive
Negative
Why do hydrogen bonds form between water molecules?
The slightly negatively charged oxygen atom of water attract the slightly positively charged hydrogen atoms of other water molecules.
Hydrogen bonds in water are _____.
Weak
What gives water its cohesive propety?
Hydrogen bonding.
What feature of water makes it a good solvent?
Its polarity
What causes water to evaporate?
When hydrogen bonds holding water molecules together are broken.
What does it mean if water has a high latent heat of vaporization?
A lot of heat is used to change it from a liquid to a gas.
Why is water having a high latent heat of vapourisation an advantage for living organisms?
Means they can use water loss through evaporation to cool down without losing too much water.
What gives water a high specific heat capacity?
Hydrogen bonds
Define specific heat capacity:
The energy needed to raise the temperature of 1 gram of a substance by 1 degree C.
What does it mean if water has a high specific heat capacity?
A lot of heat energy is needed to break up the hydrogen bonds between water molecules.
Why is water having a high specific heat capacity an advantage for living organisms?
Means water does not experience a rapid temperature change, so habitats are sustainable.
What is cohesion?
The attraction between water molecules of the same type.
Why are water molecules cohesive?
As they are polar.
What is a dipolar molecule?
A molecule with equal and opposite charges at each end.
Define Cohesion:
When the positively charged hydrogen atom of one water molecule is attracted to the negatively charged oxygen atom of another water molecule, forming a hydrogen bond
Define adhesion:
When water molecules are attracted to the impermeable walls of xylem tissue.
