Topic 1B- More Biological Molecules (Water) Flashcards
Describe waters use as a metabolite?
Describe waters use as a solvent and how is this helpful in the cytoplasm?
Describe waters uses as a temperature controller?
Describe waters use as being cohesive?
Water is a metabolite in loads of important metabolic reactions, including condensation and hydrolysis reactions
Water is a solvent, which means some substances dissolve in it. Most metabolic reactions take place in solution so water’s essential
Water helps with temperature control because it has a high latent heat of vaporisation and a high specific heat capacity
Water molecules are very cohesive (they stick together) which helps water transport in plants as well as transport in other organisms.
Describe how water is a polar molecule?
Describe why hydrogen bonds form between water molecules?
What does this hydrogen bonding give water?
Describe how water is an important metabolite?
What does a hydrolysis reaction do concerning water?
What does a condensation reaction do concerning water?
What are a lot of important substances in biological reactions?
What causes the ions to get totally surrounded by water molecules (full description)?
What does water’s polarity make it useful for?
Why is this useful in living organisms (full description)?
It has a slight (partial) negative charge on one side and a slight (partial) positive charge on the other
Because the slightly negatively charged oxygen atoms of water attract the slightly positively charged hydrogen atoms of water molecules
Gives water some of its useful properties
Many important reactions involve a condensation or hydrolysis reaction
A hydrolysis reaction requires a molecule of water to break a bond
A condensation reaction releases a molecule of water as a new bond is formed
Ionic- meaning they’re made from one positively charged atom or molecule and one negatively charged atom or molecule
Because water is polar, the slightly positively charged end of a water molecule will be attracted to the negative ion, and the slightly negatively charged end of a water molecule will be attracted to the positive ion
Makes it useful as a solvent (ie a substance capable of dissolving another substance)
This means living organisms can take up useful substances (eg mineral ions) dissolved in water and these dissolved substances can be transported around the organism’s body.
When does water evaporate (vaporise)?
What does this allow the water molecules to do?
Why is a lot of energy used up when water evaporates?
What property does this mean water has and describe it?
Why is this property useful for living organisms?
What happens when water evaporates and what two things does this do to the surface?
What is an example of this?
When the hydrogen bonds holding water molecules together are broken
Allows water molecules on the surface of the water to escape into the air as gas
Because it takes a lot of energy (heat) to break the hydrogen bonds between water molecules
This means that water has a high latent heat of vaporisation- lots of heat is used to change it from liquid to a gas
Because it means they can use water loss through evaporation to cool down without losing too much water
It carries away heat energy from a surface, which cools the surface and helps to lower the temperature
eg When humans seat to cool down.
What property do hydrogen bonds give water and explain this?
What is used when water is heated?
What does this mean?
Why is this useful for living organisms?
What does the water inside organisms do?
How does this help the organisms?
A high specific heat capacity- this is the energy needed to raise the temperature of 1 gram of a substance by 1 oC
A lot of heat energy is used to break the hydrogen bonds between the water molecules
This means there is less heat energy available to actually increase the temperature of the water
Because it means that water doesn’t experience rapid temperature changes
Remains at a fairly stable temperature
Helping them to maintain a constant internal body temperature.
What is the definition of cohesion?
What are water molecules described as and why?
What does strong cohesion help water to do and what is this very useful for?
What other property does strong cohesion give water?
What does this property explain concerning sweat and why?
What else does this property allow for?
The attraction between molecules of the same type (eg two water molecules)
Water molecules are very cohesive (they tend to stick together) because they’re polar
Strong cohesion helps water to flow, making it great for transporting substances
Strong cohesion also means that water has a high surface tension when it comes into contact with air
This is the reason why sweat form droplets, which evaporate from the skin to cool an organism down
Also the reason that pond skater, and some other insects, can “walk” on the surface of a pond.
