Water Flashcards
1
Q
Why is water vital to living organisms?
A
- water is a metabolite in lots of important metabolic reactions like condensation and hydrolysis
- water is a solvent and most metabolic reactions take place in solution (in the cytoplasm of cells)
- water helps with temperature control
- water is very cohesive which helps water transport in plants as well as in other organisms
2
Q
What is the structure of water molecules?
A
- one atom of oxygen is joined to two atoms of hydrogen by shared electrons which are pulled towards the oxygen atom
- the exposed side gives a positive charge and the unshared negative electrons give a negative charge which makes water is a polar molecule
3
Q
Why is water an important metabolite?
A
- many metabolic reactions involve a condensation or hydrolysis reaction both use water to make or break bonds
- amino acids are joined together to make polypeptides by condensation reactions
- energy from ATP is released through a hydrolysis reaction
4
Q
Why does water have a high latent heat of vaporisation?
A
- it takes a lot of energy to break the hydrogen bonds between water molecules
- so a lot of energy is used up when water evaporates
- organisms can use evaporation to cool down without losing too much water
5
Q
How does water buffer changes in temperature?
A
- the hydrogen bonds between water molecules can absorb a lot of energy before it heats up
- water doesn’t experience rapid temperature changes
- water makes a good habitat because the temperature under water is usually stable
- water inside organisms maintains a fairly stable temperature which helps maintain a constant internal body temperature
6
Q
What dos buffer mean?
A
resist
7
Q
Why does water make a good solvent?
A
- because its polar
- a lot of important substances in metabolic reactions are iconic
- since water is polar the positive end of a water molecule is attracted to the negative ion and vice versa
- the ion will be totally surrounded by water molecules and will dissolve
8
Q
Why is it important that water is so cohesive?
A
- allows water to move in columns up the xylem
- strong cohesion means water has a high surface tension when it touches air which is why sweat forms droplets which evaporate from skin to cool an organism down, its also how pond skaters walk on water
9
Q
what is a solvent?
A
something that is dissolved in other substances
10
Q
why does water make a good temperature control?
A
- it has a high latent heat capacity of vaporisation
- it has a high specific heat capacity
11
Q
what makes water molecules so cohesive?
A
-they are polar
12
Q
what doe cohesive mean?
A
-the sticking together of particles of the same substance.
13
Q
what is an ionic substance?
A
-a substance made from one positively charged atom/molecule and one negatively charged atom/molecule
