biological molecules Flashcards
what does polar mean
an uneven charge distribution across it one part of the molecule is slightly positive and the other part is slightly negative
what make water polar
oxygen atom is negative
hydrogen atom is positive
describe a hydrogen bond
a bond between hydrogen and an electro-negative atom
draw 4 water molecules being held together
why is water being a liquid at room temperature positive (3 ways)
aquatic habitat
main component of cell cytoplasm, blood plasma and tissue fluid
ideal transport medium
why is water a liquid a t room temperature
they continuously make and break hydrogen bonds, making it difficult for molecules to escape as a gas
describe how polar substances get dissolved in water
one end is positive so it will attract a negative side of water
one end is negative so it will attract a positive side of water
the ions will get totally surrounded in water molecules (e.g dissolve)
why is ice less dense that liquid water
each water molecule forms 4 hydrogen bonds to other water molecules making a spaced out lattice structure
why is ice being less dense than liquid water useful for living organisms (2)
forms an insulating layer on top of the water
it is a habitat
What is cohesion
It is the force of the attraction between molecules of the same type
How does cohesion relate to water
This occurs between water molecules due to their polar nature and hydrogen bonds forming
Why is cohesion a useful factor of water
It helps water to flow as one mass which makes it useful for transporting substances
Explain surface tension
The water molecules of the surface are hydrogen bonded to the water molecules underneath and are more attracted to those than they are to the air molecules above
Why is surface tension useful to living organisms
It creates a habitat
What is high specific heat capacity
The energy needed to raise the temperature of one gram of water by one degree
Why is high specific heat capacity useful in living organisms
Water does not experience rapid temperature changes making it a good habitat
How does water have a high latent heat of evaporation
It takes a lot of energy to break all the hydrogen bonds between the water molecules in order for it to turn from a liquid into a gas
Why is it useful for water to have a high latent heat of evaporation
Organisms make use of the evaporation of water as a cooling mechanism
What three elements make up carbohydrates
Carbon hydrogen and oxygen
What is the single monomer unit of carbohydrates called
Monosaccharide
What is a monosaccharide
A simple sugar
Give two examples of hexoses
Glucose and fructose
Give two examples of pentoses
Ribose and deoxyribose
What what is it called where many monosaccharides join
Polysaccharide
