#16 Summary of Biological Molecules

From small to large

1. The larger biological molecules are made from smaller molecules. Polysaccharides are made from monosaccharides, proteins from amino acids, nucleic acids from nucleotides, lipids from fatty acids and glycerol.

# 15. Water

About 80% of the organism's body is H₂O.

Its molecule has a small negative charge (β-) on the O atom                                        a small positive charge (β+) on each H atom. 

                         This is called a dipole.

This makes H₂O an excellent solvent.

#14. Globular and fibrous proteins - haemoglobin and collagen

Globular and Fibrous are 2 main types of proteins with a 3D structure.

#13. Protein - Primary, Secondary, Tertiary and Quaternary structure

Amino acids can be linked together in any order to form a long chain - polypeptide.

Protein molecules can be made up of the same polypeptides or different polypeptides.

#12. Proteins - amino acids, peptid bonds

Proteins are large molecules made of long chains of amino acids.

#11. Lipids - Triglycerides and Phospholipids.

Lipids:
- Include triglycerides + phospholipids.
- Molecules contain C, H, O atoms
- Very small proportion of O.
- Insoluble in water.

#10.Tests for carbohydrates

Tests for Reducing sugars, Non-reducing sugar and Starch.

#9. Carbohydrates - Polysaccharides

Molecules contain hundreds/thousands of monosaccharides linked into long chains.
Molecules are enormous --> the majority do not dissolve in water --> good for storing energy (starch and glycogen) or for forming strong structures (cellulose).

#8. Carbohydrates - Monosaccharides, disaccharides

Carbohydrates:
- Sugar polymers
- Molecules contain C, H, O atoms
- H atoms are twice as many as C or O atoms (C₆H₁₂O₆)

#7.2 Biological molecules - Syllabus 2016 - 2018

2.1    Testing for biological molecules
2.2    Carbohydrates and lipids
2.3    Proteins and water

#7.1 Biological molecules - Syllabus 2015

• Structure of carbohydrates, lipids and proteins and their roles in living organisms
• Water and living organisms