Biology - Chapter 1, Biological Molecules.

A-Level Biology - Chapter 1. KLA content.

Monosaccharide

A singular sugar molecule.

Disaccharide

Two sugar molecules.

Polysaccharide

Many sugar molecules in a polymer.

Monomer

A molecule which chemically bonds to others of the same molecule in order to form a polymer.

Polymer

A chain structure of monomers bonded together.

Condensation polymerisation

Forming a polymer from monomers, releasing water in the process.

Hydrolysis.

Splitting of a polymer into its monomer components by adding water.

Glycosidic bonds.

Bonds which form following condensation reactions, wherein 2 monomers are connected via a shared oxygen molecule.

Reducing sugars

Carbohydrates which can donate an electron to other molecules. All monosaccharides.

Non - reducing sugars

Sugars which cannot donate an electron to other molecules. Sucrose.

Glucose

The monosaccharide produced by plants and algae during photosynthesis.

Maltose

Alpha glucose + alpha glucose.

Sucrose

Alpha glucose + fructose.

Lactose

Alpha glucose + galactose.

Alpha glucose

Formation of glucose with both OH groups on the bottom of the molecule.

Beta glucose

Formation of glucose with on OH group on the bottom and one OH group in the opposite corner of the molecule.

Polysaccharide usage

Used as storage.

Benefit of polysaccharides being insoluble

They have no osmotic effect and will not be absorbed into the blood.

Benefit of polysaccharides being compact

Able to store lots of sugar / potential energy.

Benefit of polysaccharides being easy hydrolysied

They can be easily broken down into glucose used in respiration to release energy.

Polysaccharide examples

Starch, glycogen, and cellulose.

Amylose

Linear polymer of a-glucose in a coiled structure, creating a helix shape.

Amylopectin

A-glucose polymer with a linear backbone, but many branches, allowing enzymes to get in quickly and hydrolise the starch.

Glycogen

The storage of a-glucose in animals.

Structure of glycogen

Linear backbone with a huge amount of branches allowing very quick hydrolysation of the polymer, releasing glucose for respiration.

Cellulose usage

Cellulose makes up plant cell walls.

Cellulose structure

Beta-glucose with each monomer being flipped compared to those besides it. This creates hydrogen bonds between parallel chains, forming strong fibres known as microfibrils.