Molecules Flashcards
Water is/can… (5)
- a reactant
- a solvent
- a habitat
- transports substances
- help with temperature control
Structure of water
There is one atom of oxygen joined by two hydrogen atoms as the shared negative hydrogen electrons are pulled towards the oxygen atoms. The unshared negative electrons on the oxygen give it a slightly negative charge, making it a polar molecule. It also contains hydrogen bonds due to the difference in charges
What is specific heat capacity
The energy required to raise the temperature of 1 gram of substance by 1 degree celcius
What do hydrogen bonds absorb
Lots of energy
Does water have a high or low specific heat capacity
High
What is high latent heat of evaporation
Lots of energy is used up when water evaporates
Does water have a high latent heat of evaporation
Yes due to the hydrogen bonds
What is cohesion
The attraction between molecules of the same type e.g two water molecules as they are polar
Why is cohesion useful
Helps water to flow so useful for transporting substances
What property does a polar molecule have
It is a good solvent so can dissolve
Why is ice less dense than water
Ice molecules are held further apart so ice is less dense than water therefore ice will float
What are carbohydrates made from
Polymers called Monosaccharides
What is a hexose monosccharide
Monosaccharide with six carbon atoms
Two forms of carbohydrates
Alpha and beta
What is the order of the alpha ring
Hydrogen on top and the hydroxyl underneath
What is the order of the beta ring
The hydroxyl is on top the hydrogen is on top
What is a monosaccharide with 5 carbon atoms called
Pentose monosaccharide
What are monosaccharides joined together by
Glyosidic bonds
What three elements are carbohydrates made up of
Carbon, hydrogen and ocygen
For every carbon atom how many hydrogen and oxygen atoms are there
2 hydrogen atoms
1 oxygen atom
What happens during carbohydrate synthesis and it’s name
A hydrogen atom on one monosaccharide bonds to a hydroxyl group releasing a water molecule - called condensation
What happens during the reverse of carbohydrate synthesis and it’s name
A molecule of water reacts with the glycosidic bond breaking it apart - called hydrolysis
What is formed when two monosaccharides join together
Disaccharide
General term for mono/disaccharides
Sugar
More than two monosaccharides are
Polysaccharides
Starch is…
The main energy storage material in plants
Glycogen is…
The main energy storage material in animals
Cellulose is…
The major component of cell walls in plants
What is cellulose made from
Long, unbranched chains of beta glucose bonding by hydrogen bonds to form straight cellulose chains. There are fibres called microfibrils providing structural support
What do animals store excess glucose as
Glycogen
Structure of glycogen
Polysaccharide of alpha-glucose similar to amylopectin but with lots of side branches so stored glucose can be released quickly which is important for energy release and also very compact so good storage