Biology: Properties of Water Flashcards
High Specific Heat Capacity: Definition
A lot of energy is required to raise the temperature of water (one gram of water by one degree).
High Specific Heat Capacity: Importance to Living Things
Water resists temperature changes, it buffers them. This is beneficial for aquatic organisms because the temperature of the water they live in does not change rapidly. The temperature is more stable than air. Living things contain a high proportion of water so they can buffer internal temperature changes. The high specific heat capacity of water makes thermoregulation easier. This temperature control is important to maintain the optimum temperature for enzymes to act at. Surface tension of water enables small animals to walk on the surface of the water. Surface tension occurs because the top layers of water molecules do not have any water molecules above them to which they can be attached. There is therefore a net attraction downwards and the surface tension produced supports the body of an insect.
High Latent Heat of Vaporisation: Definition
A lot of energy is required to evaporate water (1 gram)
Metabolite: Definition
A substance that is involved in a chemical reaction as a reaction or as a product.
High Latent Heat of Vaporisation: Important to Living Things
The evaporation of water has a large cooling effect because water has a high latent heat of Vaporisation. Sweat produced by mammals is mainly water. A large amount of heat energy is removed from the skin and the blood within the skin capillaries to evaporate the sweat so there is a large cooling effect. This cooling prevents temperature rises that could lead to enzymes denaturing. Transpiration of water (evaporation and loss of water from leaves) cools plants.
Metabolite: Importance to Living Things
Molecules can be broken down into smaller ones by adding water to break bond between chemical units. These reactions are called hydrolysis reaction. APT is the immidiate energy source for cells, and it is hydrolysed to release the energy for the cell’s activities.
Water is produced when bonds form to join small molecules together to produce larger molecules. These reactions are called condensation reaction. A condensation reaction is used to join ADP and Pi to make ATP during respiration.
Cohesion: Definition
One water molecule ‘sticks’ to the next via hydrogen bonding
Solvent: Definition
A substance capable of dissolviing another substance (a solute)
Cohesion: Importance of Living things
Water molecules can form a continuous column of water so that mass flow can occur. If one water molecule moves then the other water molecule will flow with it as they are joined via hydrogen bonds (there is cohesion), therefore there can be bulk transport of substances down the pressure gradients. For example, water is in a continuous column within xylem vessels of a plant so there can be mass flow from the roots from the leaves.
Solvent: Importance to Living Organelles
Many substances can dissolve in water. Substances dissolved in water are free to move around and react with other molecules. Chemical reactions in living things (metabolic reactions). Water is the medium for chemical reactions. Substances dissolved in water can be transported. Plants transport dissolved ions in the water of the xylem. Water is used to dissolve substances that are excreted from the body e.g. urine is a solution containing urea and excess ions.
