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.
- 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.
-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.
-Water molecules are attracted to each other allowing them to move into small spaces by capillary action.
-Solid water is less dense than liquid.
-Ice floats on water and insulates it allowing aquatic animals to survive beneath it.
-H and OH, level of H used to determine pH.
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.
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.
Composed of C H & O
Containing one or two sugar molecules are simple carbohydrates. Many sugar molecules are called complex carbohydrates.
Single sugar unit and usually has thee formula c6h12o6. Most important monosaccharide is 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.
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.
-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.
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