Water

what type of molecule is water

a Dipolar molecule (two different regions that are charged)

why does water have an unevenly distributed charge

due to the fact that the oxygen atom is slightly negative, and the hydrogen atoms are slightly positive

What are the 5 key properties of water

• it is a metabolite (in condensation and hydrolysis reactions)

• An important solvent in reactions

• Has a high heat capacity, it buffers temperature

• Has a large latent heat of vaporisation, providing a cooling effect with loss of water through evaporation

• has a strong cohesion between water molecules (this supports water columns and provides surface tension)

How do Hydrogen bonds form

they form between different water molecules between the oxygen and the hydrogen atoms

What does water being a metabolite mean

its involved in lots of chemical reactions for metabolism eg water being used in photosynthesis, hydrolysis and condensation reactions, photolysis

What do we mean when we say water is a really good solvent?

it has the ability to dissolve many substances

How is water being a good solvent useful?

• plasma can dissolve in the water then it is easier to transfer as 90% of plasma is made of water, and plasma is what transports molecules long distances around your body

• also allows plants to easily transfer subtances around the xylem or phloem

what molecules can water dissolve and cannot dissolve

-water molecules can dissolve polar molecules (hydrophilic)

-water cannot dissolve non-polar molecules (hydrophobic)

What do we mean when we say water has a High specific heat capacity?

this means that a lot of energy is required to raise the temperature of water, this is because some of the heat energy is used to break the hydrogen bonds between water molecules

how is water having a high specific heat capacity useful?

its useful to organisms as it means the temperature of water remains relatively stable, even if surrounding temperatures fluctuate significantly. Therefore, internal temps of pants and animals remain relatively constant despite the outside temp

Why is it important for water to have a high specific heat capacity

so that enzymes do not denature or reduce the activity with temperature fluctuations (provides stable environment for aquatic organisms)

what occurs if the animal of plant (cells) get too cool or too hot

1. Not enough kinetic energy for sucessful collisions between the enzyme and the substrate

2. enzyme denatures if too hot

what do we mean when we say water has a large latent heat of vaporisation?

means that a lot of energy is required to convert water in its liquid state to a gaseous state, this is due to the hydrogen bonds as energy is needed to break the hydrogen bonds between water molecules to turn into gas

How is water having a large latent heat of vaporisation an advantage to organisms

it means water will provide a significant cooling effect for e.g when humans sweat they release water onto their skins, large amounts of heat energy from the skin is transferred to the water to evaporate it, cooling the organism

what do we mean by cohesion

water molecules sticking together by hydrogen bonds

Advantages of cohesion

• water can move up the xylem in plants in a continuous column of water rather than moving up a droplet at a time ( as water molecules can stick together), this is an advantage as it is easier to pull up a column of water rather than separate droplets

• provides surface tension to water which enables small invertebrates (some animals) to move and live on the surface providing a habitat protecting them from predators

how does cohesion protect certain animals from predators

cohesion provides surface tension to the water allowing certain anima