Biomolecules- Water Flashcards
What is water a medium of?
Metabolic reactions
What is it meant by the term dipole?
It has a positively charged (hydrogen) and a negatively charged (oxygen) with no overall charge. The molecule with separate charges is polar.
What bonds are found between the water molecules?
Hydrogen bonds form between the Delta plus on the hydrogen atom and the Delta minus on the oxygen atom. Hydrogen bonds are weak but in very large numbers make them hard to separate when present in water, giving water a wide range of properties.
Why is it important that water is a solvent?
It allows living organisms to obtain their key elements from an aqueous solution. As water is a dipole they attract charged particles such as ions and other polar molecules such as glucose. These dissolve in water so chemical reactions can take place in the solution. Water acts as a transport medium
Give two examples of water as a solvent
Plasma transports dissolved substances
Water also transporting minerals in the xylem and sucrose and amino acids in the phloem
Explain why water is a metabolite?
It is used in many biochemical reactions as a reactant e.g. with CO2 to produce glucose in photosynthesis. Many reactions in the body involve hydrolysis where the water splits the molecule.
Why does water have high specific heat capacity?
The hydrogen bonds between the water molecules restricts the movement resisting an increasing kinetic energy therefore restricting a rising temperature.
Why is having a high specific heat capacity good?
It prevents large fluctuations in its temperature which is important in keeping aquatic habitats stable so that organisms won’t have to adapt to extreme temperatures as well as allowing enzymes to work efficiently
Why is it important that water has a high latent heat of the evaporation?
It is important and temperature control as what is produced in the cooling of the body this means it won’t evaporate.
What is cohesion within water?
It is when the water molecules attract each other forming hydrogen bonds as there are many molecules which stick together in the lattice, it allows columns of water through the xylem vessels and plants.
What is high surface tension?
It is when molecules in a liquid are affected by various intermolecular forces of attraction.
Why is it good that water has a high surface tension?
It provides a habitat for many aquatic species as they can survive the surface.
Does water have a high or low density?
Water is denser than air, water has a max density of 4°C. Ice is less dense than water as hydrogen bonds hold the molecules further apart than a liquid.
Why is it good that water has a high density?
To provide a habitat for organisms due to support and buoyancy. It is a good insulator and prevents large bodies of water from losing heat and freezing completely so organisms can survive beneath it.
Why is it important that water is transparent?
It allows light to past through which allows aquatic plants to photosynthesise effectively.
