Water Flashcards
Water is involved in many metabolic reactions, what is this called
Water is a metabolite
Name two reactions water is involved in
Condensation
Hydrolysis
Describe condensation reactions
Smaller molecules join to form larger molecules
Name the features of condensation reactions
- water is produced
- creates bonds
Describe hydrolysis reactions
Large molecules are broken down into smaller molecules
Features of hydrolysis reactions
- water is used
- breaks bonds
Example of hydrolysis reaction
Digestion
Why is water used as a transport medium
Because it’s a solvent and a metabolite
What does water dissolve and why
Hydrophilic material because the molecules are compatible
Thermal properties of water
- high specific heat capacity
- large latent heat of vaporisation
- thermostable
What does it mean that water had a high HC
Large amounts of energy is required to change its temperature by 1°C
What does water do to changes in temperature
Buffer them
What shape is water
V-shaped
How would you describe water
As a polar molecule
Why is water polar
Delta + charge and a delta - charge distributed unevenly
Why does water have a large SHC
Water molecules stick together with extensive hydrogen bonds, lots of energy needed to break these bonds
How does water act as a buffer
Minimises temperature fluctuations in living things due to its high SHC
What does it mean that water has a large latent heat of vaporisation
Large amounts of energy needed to change the state of water from liquid to gas
How does thermostability change in water
The greater the volume of water the greater the stability
How does water provide a cooling effect
Water particles are hydrogen bonded with extensive hydrogen bonds so it requires lots of energy to break these bonds and change state- evaporate (greater amount of energy lost, the greater the cooling effect)
Define hydrophilic
Substances attracted to water (polar/ionic substances)
What substances dissolve in water
Hydrophilic substances
Define hydrophobic
Substances that repel water (non polar)
Give an example of a hydrophobic substance
Lipids
Why is water needed to break down large molecules in digestion
Large particles are too big to move by transport and insoluble
Define digestion
Breakdown by hydrolysis of large, insoluble molecules into small soluble molecules
What does it mean that water molecules are cohesive
They ‘stick’ together via hydrogen bonding
Where are hydrogen bonds found
Between water molecules
In what tube does cohesion allow the transport of water
Xylem
What is tension created by
Cohesive water particles and hydrogen bonding
How do pond skaters float
They have legs made out of hydrophobic material, repelling water allowing them to stay afloat due to surface tension
describe the features of ice
- molecules have four hydrogen bonds
- less dense than water
- thermally insulates
- provides a habitat on surface
how is surface tension created in water
water is cohesive and hydrogen bonds to other water molecules
what organism does surface tension provide habitats for
pond skaters
how is water a solvent
water is polar so dissolves charged molecules and any other polar molecules
how is water useful for photosynthesis in plants
- used in photosynthesis to create sugars
- transparent to allow aquatic plants to photosynthesise
