1. The building blocks of life…
Macromolecules
The building blocks of life…

2. Macromolecules
Cells are composed of several types of biological macromolecules.
These function as energy-storage molecules, structural components, and in information storage, and are primarily composed of carbon, hydrogen and oxygen.

3. Carbohydrates carbon, hydrogen & oxygen in a 1:2:1 ratio
exist as monosaccharides, disaccharides and polysaccharides
among the most abundant molecules on Earth

4. Monosaccharides “single sugars” general formula is (CH2O)n
glucose (top) and ribose (bottom) are monosaccharides

5. Disaccharides “double sugars”
formed by dehydration synthesis from two monosaccharides
sucrose, maltose, and lactose are all disaccharides

6. Synthesis of Maltose
- glucose
-glucose
maltose

7. Polysaccharides
straight or branched chains of monosaccharides connected by glycosidic linkages
storage (e.g. starch, glycogen) or structural (e.g. cellulose, chitin)

8. Polysaccharide Structure
Images from MIT Biology Hypertextbook, (1996) (3/9/2001)

9. Proteins
proteins are chains of amino acids connected by peptide linkages
order of amino acids for a particular protein is determined by the gene which codes for it

10. Amino Acid Structure all amino acids have the same basic structure
“R” group is different for each amino acid
amino group
carboxyl group

11. Peptide Linkages
cysteine
glycine
peptide linkage

12. Levels of Protein Structure
Primary
the specific sequence of amino acids
coded by DNA
Protein structure images from the Online Biology Book, M.J. Farabee, (2001) (3/9/2002)

13. Secondary
the folding or coiling of the amino acid chain
caused by interactions between “R” groups
-Helix
-Pleated Sheet

14. Tertiary
the unique three-dimensional shape of the protein
enzymes are globular proteins
collagen is a fibrous protein

15. Quaternary
interactions between separate polypeptide chains, or “subunits”
hemoglobin is composed of four subunits

16. Lipids lipids are a group of hydrophobic molecules
“neutral fats” are uncharged lipids composed of glycerol and fatty acids
fats are solid at room temperature
oils are liquid at room temperature
steroids and phospholipids are amphiphilic

17. Steroid Structure
steroids all have the same basic structure of four fused hydrocarbon rings
cholesterol is used to synthesize many other steroids in the body
cholesterol

18. Phospholipid Structure
glycerol backbone has two fatty acids and one charged inorganic phosphate group attached
primary component of cell membranes
Image from the Online Biology Book, M.J. Farabee, (2001) (3/9/2002)

19. Triglycerides triglycerides are neutral fats
glycerol is the “backbone” molecule
fatty acids attach to glycerol by ester linkages
saturated fatty acids have no double bonds between carbons
unsaturated fatty acids have at least one double bond between carbons

20. Triglyceride Synthesis
3 fatty acids
glycerol
ester linkage
triglyceride

21. Nucleic Acids Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA)
composed of nitrogen-containing “bases” attached to a backbone of alternating pentose sugars and inorganic phosphate
function in information storage (DNA) and transfer (RNA)

22. “Bases” of DNA & RNA Purines Pyrimidines adenine thymine guanine
cytosine
uracil

23. DNA deoxyribose sugar adenine, guanine, cytosine, thymine bases
arranged in a double helix
Image from the Online Biology Book, M.J. Farabee, (2001) (3/9/2002)

24. RNA ribose sugar adenine, guanine, cytosine, uracil bases
single-stranded

25. References
MIT Biology Hypertextbook(1996) (3/9/2001)
Farabee, M.J., (2001) An Online Biology Book. Chemistry 2: Water and Organic Molecules (3/9/2002)
A.C.D. Labs (2002) ChemSketch (Freeware), available for download at Used for molecular structure diagrams.