hydrogen bonding

Explain the structure of cellulose

• Cellulose is made of β-glucose joined by β-1,4 glycosidic bonds.

• The chains are straight and unbranched, with alternate β-glucose molecules inverted.

• Hydrogen bonds form between chains, bundling them into microfibrils with high tensile strength.

Explain the structure of starch

• α-glucose molecules join by condensation reactions, removing a molecule of water.

• This forms α-1,4 glycosidic bonds between glucose molecules.

• In amylopectin, some α-glucose molecules also form α-1,6 glycosidic bonds, creating branches.

Compare the structure of glucose and starch

• Starch: Made of α-glucose; amylose is coiled and amylopectin is branched.

• Cellulose: Made of β-glucose; chains are straight and unbranched.

• Both: Glucose molecules are joined by glycosidic bonds.

Explain the secondary structure and what bonds it has

• The regular folding of a polypeptide chain into α-helices and β-pleated sheets.

• Hydrogen bonds

Explain the tertiary structure and what bonds it has

• The overall 3D shape of a polypeptide caused by further folding of its secondary structure.

• Hydrogen

• Ionic

• Disulphide

• Hydrophobic interactions

Explain quaternary structure and the bonds it contains

• The arrangement of two or more polypeptide chains (subunits) into one functional protein

• Hydrogen

• Ionic

• Disulphdie

• Hydrophobic interactions

Describe the primary structure and what borne it has

• The specific sequence of amino acids in a polypeptide chain.

• Peptide bonds