2.2- Biological Molecules Flashcards
(15 cards)
What is a condensation reaction
A reaction that occurs when two molecules are joined together with the removal of water
What is a hydrogen bond
A weak interaction that can occur wherever molecules can contain a slightly negatively charged atom bonded to a slightly positive charged hydrogen atom
What is a hydrolysis reaction
A reaction that occurs where a molecule is split into two smaller molecules with the addition of water
What is a monomer
A small molecule which binds to many other identical molecules to form a polymer
What is a polymer
A large molecule molecule made from many smaller monomer molecules
What is a Covalent bond
Where electrons are shared between 2 or more atoms
What makes water a polar molecule
Oxygen is more electronegative than Hydrogen as it has more positively charged protons, which attracts shared paired pairs of electrons more readily
Molecules that have slight differences in charge are called polar
Draw a hydrogen bond between water molecules
Dipoles drawn correctly
Dotted line between O and H of different molecules
Hydrogen bond labelled
Why is it important that water is a liquid?
Without Hydrogen bond, water would be a gas. This is important as it serves as a habitat for living things, a component of tissue, a reaction medium and a transport medium
Water is a solvent and a transport medium:
- Polar water molecules are attracted to other polar/ charged molecules e.g sugar/salt
- The water can then transport these dissolved substances
Why is it useful that oil and water substances don’t mix
Useful as cell membranes are made of phospholipids which don’t mix with water and so wall off different cells
Ice is less dense than water: FINISH OFF
Water has a higher density than ice
As when ice forms, the molecules can form 4 hydrogen bonds each,
Surface tension
Cohesion between water molecules at the surface creates surface tension
Cohesion and adhesion
Cohesion- water molecules hydrogen bond to other water molecules
Adhesion- Water molecules hydrogen bond to other polar molecules
High specific latent heat of vaporisation:
Latent heat= energy require
