Water Flashcards
Name some structures of water…
Molecules interact via hydrogen bonds
Has ‘bent shape’ (non-linear)
Polar molecule - permanent dipole and uneven charge distribution
Name some properties of water…
Lower density on freezing
High specific heat capacity
High latent heat of vaporisation
Hugh melting and boiling point
Cohesion
Adhesion
What does water properties allow it to do?
Act as a medium transport
Act as a medium bio mechanical reactions
Act as a habitat
What is cohesion?
The tendency of water molecules to stick to each other
What is adhesion?
Refers to tendency of water molecules to stick to other things.
What does hydrophobic mean?
Water repelling
What is hydrophilic?
Water attracting
What is specific heat capacity?
The amount of energy required to raise the temperature of 1kg of water by 1•c
What does water having a large specific heat capacity mean?
Can absorb large amounts of heat energy before its’ temperature raises by a significant amount.
What does water having a large latent heat mean?
Absorbs large amount of heat energy while changing from water to vapour
What does the cohesion of water lead to?
High surface tension
Allows organisms to use water surface as a habitat
Freezing of water… what happens?
Water becomes less dense, when freezing water molecules arrange themselves so that they can adopt the optimal hydrogen - bond arrangement.
What does polar mean?
A molecule or bond has an uneven distribution of electrons.
What’s the structure of water?
One atom of oxygen, Two atoms of hydrogen - joined by shared electrons.
Oxygen atom have slight negative charge and hydrogen atoms have slight positive charge
What makes water a dipolar molecule?
Partial negative charge on one side and partial positive charge on the other
How does water being dipole make it good at transporting substances?
Slight positive and slight negative charge on either side makes water cohesive meaning it is a good solvent due to the attraction between 2 water molecules as they stick together making it easier for water to flow therefore a good substance transporter
Why do multicellular organisms need mass transport systems?
In single felled organisms materials can diffuse directly across the cell membrane therefore the diffusion rate is quick
Whereas in multicellular organisms diffusions cross the membrane is slow because of the large distance substances have to travel
What is a mass transport system?
Used to carry raw materials from specialised exchange organs and to remove metabolic waste
In mammals the mass transport system is the circulatory system
Individual cells in tissues and organs get nutrients and oxygen from the blood and dispose of metabolic waste into the blood
