Helena Dalakouras
Biology Unit 3
Area of study 1
Chapter 1 ‘The chemical nature of cells’

Quick summary of the synchrotron
-A ‘super microscope’ used to examine molecules in fine detail.
-A particle accelerator that produces extremely brilliant light ranging from:
Lower energy infra-red High energy hard X-rays
-Studies materials in forms
(gas liquid solid) and is applied in many fields.
-Helped discover the reasons behind Phar Laps death.

Water: ‘A unique compound’
Properties of water
Polar because the O atom within the molecule exerts a stronger pull on the shared electrons than the H atoms causing the water molecule to have partially charges areas
This allows water molecules to be attracted to each other and gives many properties.
UNIVERSAL SOLVENT
- Ionic compounds and polar molecules readily in water.
- Water forms hydration shells around ions to prevent them from reforming neutral compounds.
-Non-polar molecules cannot dissolve in water but often form interfaces with it which are frequently the sites of biological reactions.
COOLANT
-Water has a high vaporization temperature as the H bonds allow it to absorb a lot of the heat before changing state.
-Also of high heat capacity to carry heat around the body.
ADHESION
-Water molecules are attracted to each other allowing them to move into small spaces by capillary action.
DENSITY
-Solid water is less dense than liquid.
-Ice floats on water and insulates it allowing aquatic animals to survive beneath it.
IONISES
-H and OH, level of H used to determine pH.

Organic molecules
Sub-units that are formed and bonded are called polymers. Sub units are monomers. The joining of monomers involves the release of a water molecule.

Monomers Polymers
Building blocks of cell: Larger units of the cell:
Sugars -> Polysaccharides
Amino acids -> Proteins
Fatty acids -> Fats, membranes
Nucleotides -> Nucleic acids

The kinds of organic molecules that will be considered are carbohydrates, proteins, lipids and nucleic acids.
For each the following will be examined:
-The basic unit of structure
-How the units will combine to form complex molecules
-Where each of the molecules are found in cells
-Functions of the molecules.

Carbohydrates
Composed of C H & O
Containing one or two sugar molecules are simple carbohydrates. Many sugar molecules are called complex carbohydrates.

Monosaccharides
Single sugar unit and usually has thee formula c6h12o6. Most important monosaccharide is glucose.
Glucose
-A product of photosynthesis.
-During the formation of glucose in plants, energy of the sun is transformed into energy in glucose molecules.
-Energy source in plants and animal’s
-Glucose is a fundamental unit for the formation of both disaccharides and polysaccharides.

Disaccharides
Formed when two monosaccharides combine. Most familiar example is sucrose.
-E.g. of disaccharide is lactose and maltose.
-Sucrose is the form in which carbohydrate is transported in plants. Formed by combinating with fructose.

Polysaccharides- complex carbohydrates
-Polymers of sugar molecules. Most common sugar component is glucose.
-Structure of polysaccharides starch, glycogen and cellulose. All of these are composed entirely of glucose yet their structures and properties are different from one another.
-these differences are because of the way the glucose molecules are linked together.
Glycogen
-Form of energy storage in animals.
-When carbohydrates are digested, glucose is absorbed- carried to the liver- then to all the cells of the body- if there is excess to body requirements- it is converted into glycogen by the liver storage (able to store 100 grams of this)- muscles are the next storage option and can store 300grams of glycogen- if this is all filled then the excess is turned to fat storage.
Starch
Glucose is distributed around a plant in this form.
-Some plants store excess requirements in this form, starch is chief form of storage by most