The Structure and Function of Large Biological Molecules_Chapter 5

1. What are the four main molecules for life?

2. How does the synthesis and breakdown of polymers work?

3. What are the elemental compositions, general formulas, types and uses of Carbohydrates ?

For main molecules for life :

Carbohydrates, lipids, proteins and nucleic acids are the four main molecules which are

important for life. Carbohydrates, proteins and nucleic acids are huge so they are called macromolecules but they are also polymers which are composed by more than 2 monomers.

The synthesis and breakdown of polymers :

Monomers get together to create polymers. While this process since they are covalently bonding a water monomer gets lost. This is Dehydration Reaction. This process is facilitated by enzymes which are specialized macromolecules that speed up chemical reactions in cells.

Polymers break into monomers by Hydrolysis which is the opposite reaction of Dehydration so a water molecule comes. Hydrolysis breaks polymers by adding H20.

The structures and functions of Carbohydrates :

Carbohydrates are used for fuel, building materials and receptors. General formula of it is CH2O.There are 3 kinds of carbohydrates according to their number of sugar. Monosaccharides are the simplest carbohydrates since they just have 1 sugar molecule which is either glucose or fructose. They both have the sameformula which is C6H12C6 but their placements are different. Disaccharides are composed by 2 sugar molecules joined by a glycosidic linkage. It might be glucose + fructose, glucose+galactose or glucose+glucose. Polysaccharides are composed by more than 2 sugar molecules. They are basically polymers since they have tons of repeating units of a monosaccharide. Starch, glycogen, cellulose and chitin are polysaccharides.

5 main facts about this chapter :

. Proteins, carbohydrates and nucleic acids are hydrophilic but lipids are hydrophobic.

. A saturated fatty acid has a single covalent bond between each pair of carbon atoms, and each carbon has two hydrogen bonded to it.

. A phospholipid looks just like a lipid except that one of the fatty acid chains is replaced by a phosphate group (-PO3-2).

. There are four levels that describe the structure of a protein.

1. Primary structure

2. Secondary structure

3. Tertiary structure

4. Quaternary structure

. DNA is a polymer of nucleotides which are Adenine, Thymine, Cytosine, Guanine.

Video about structure of protein :

http://www.youtube.com/watch?v=lijQ3a8yUYQ

On this chapter, we learnt 4 main molecules that our body needs. Carbohydrates, proteins, nucleic acids and lipids. We learnt how polysaccharides are made by, what the structure of each of these molecules, and their importance for life. There are 5 different protein functions which are structural proteins, enzymes, storage proteins, transport proteins and defensive proteins.We also differ RNA from DNA by their different nucleotides which are Uracil and Thymine.