Topic 1 - Year 1 - Biological Molecules - Water Flashcards
Water is a metabolite in lots of important metabolic reactions , what is meant by a metabolite ?
A reactant (substance) involved in a metabolic reaction.
Why is water useful for controlling tempraure?
Water is good at temperature control as it has a high latent heat of vaporisation and a high specific heat capaity.
What is the chemical formula of water?
H2O
Why does the side of the molecule where the oxygen lies in H20 have a more negative charge?
The oxygen atom has a higher electronegativity than the hydrogen atoms so the hydrogens electrons are pulled closer the oxygen atom. This gives the side with oxygen a slightly negative charge as there are more electrons in the area and the side containing hydrogen a slightly positive charge as there are fewer electrons in the area.
Why is water an important metabolite?
Hydrolysis and condensation reactions are metabolic they occur to keep a living organism alive , in each of these reactions water is a product or reactant hence is an important metabolite (substance used in the reaction).
Why is water a good solvent?
Water is a good solvent as it is polar, one side of the molecule (the side where the oxygen atom lies) is slightly negative while the other side of the molecule (where the 2 hydrogen atoms lie) is slightly positive. A lot of important substances in biological reactions are ionic (charged). The polar water molecules are attracted to the charged ions and completely surround them . This dissolves the substances.
What is latent heat energy?
Latent heat energy is the energy thats needed to change a substance from one state to another.
Which bonds must be broken to allow water to be evaporated (vaporised) ?
Hydrogen bonds
Why does water have a high latent heat of vaporisation?
Water has a high latent heat of vaporisation as hydrogen bonds hold water molecules together in a liquid. To vaporise the liquid water the hydrogen bonds must be broken , breaking these hydrogen bonds allows the water on the surface of the water to escape into the air as gas. It takes lots of energy to overcome the hydrogen bonds between water molecules so lots of energy is used when water evaporates , consequently water has a high latent heat of vaporisation.
Why is the fact water has a high latent heat of vaporisation important to living organisms?
Water’s high latent heat of vaporisation is useful to living organisms as it means that they can cool down by loosing water by evaporation without loosing too much water.
When water evaporates it carries away heat energy from the surface which cools the surface and helps lower the temperature. Waters high latent heat of vaporisation means that a little bit of water evaporated from the surface uses lots of energy to evaporate cooling the organism as high quantities of energy are used / carried away.
What does to buffer mean ?
To buffer means to resit
Why can water buffer changes in temperatures?
Water can buffer changes in temperature as it contains hydrogen bonds. Hydrogen bonds give water a high specific heat capacity. specific heat capacity is the energy needed to raise 1g of substance by 1 degree. When water is heated a lot of the eat energy is used to break the hydrogen bonds between molecules this means there is less energy left to raise the actual temperature of the water, this means water has a Hugh specific heat capacity - it takes a lot of energy to heat it up , so it doesn’t normally undergo rapid changes in temperature therefore is a good buffer for temperature.
What is specific heat capacity?
The amount of energy needed to increase the temperature of 1g of substance by 1 degree centigrade.
Why is water a cohesive molecule?
Water is a cohesive molecule (it sticks to other water molecules) because it is polar.
What does the cohesive nature of water allow into do?
The cohesive nature of water allows it to flow making it great for transporting substances, it also gives water a high surface tension
