1. Carbon and Assembling Biomolecules
SGN 4
Biomolecules – the four major groups of molecules that, together with water and ions, are the primary building blocks of life
Biomolecules are primarily made of carbon

2. Protein Carbohydrate Lipid
Biomolecules, whether big or small, are constructed with an inner chain of carbon atoms, to which are joined hydrogens or groups of elements, called functional groups (or chemical moieties)
Protein
Carbohydrate
Lipid

3. Molecules that include carbon chains are called organic molecules; in nature these originate in biological processes
Carbon is abundant and versatile – the atom is tetravalent and so is able to form four stable, covalent bonds (single, double or triple) with a variety of other biologically important elements

4. Triglyceride A type of lipid
Carbon backbones and functional groups
Simplest arrangement of atoms in biomolecules = hydrocarbon chains
Not typically found by themselves in organisms (because they are by themselves hydrophobic in a watery environment) but some molecules do have significant hydrocarbon regions
Molecules with a hydrophobic region and a hydrophilic region and are called amphipathic molecules
Long carbon chains are used as energy storage (fats and oils) and when insoluble properties are important (cell membrane, waxes)
Triglyceride
A type of lipid

5. In complex organic structures collections of atoms branch from the carbon backbone; these are called functional groups and they are important in giving molecules their chemical properties For example, the difference between the sex hormones lies only in a few functional groups The difference between deoxyribose and ribose, essential in distinguishing DNA from RNA, lies in one functional group Students should know the name, formula, atomic orientation, general properties of the 7 functional groups discussed in lecture

6. 1. Hydroxyl group

7. 2. Carboxyl group

8. 3. Carbonyl group

9. 4. Phosphate group

10. 5. Methyl group

11. 6. Amino group

12. 7. Sulfhydryl group

13. Biomolecules range in size but many can be very large
Large proteins can be made of millions of atoms while a DNA double helix is made of billions of atoms

14. Most large biomolecules (also called macromolecules) are composed of small, repeating, similar or identical, molecular subunits, called monomers
When composed in this way the large biomolecules are called polymers
Carbohydrates
Proteins

15. Simple chemical reactions build up organic polymers and break them down Monomers are typically joined together by a dehydration reaction (also called a condensation reaction) One functional group with an –OH joins with another with an –H, expelling an H2O in the process and forming a covalent bond Anabolic reactions build up molecules and often require an input of energy (which makes them endergonic reactions)
Forming a long protein
Forming a long
carbohydrate

16. Polymers are typically disassembled with hydrolysis reactions
At a particular bond the polymer absorbs an H2O, donating an –OH to one side of the bond and an –H to the other, breaking the covalent bond
Catabolic reactions break down molecules and typically release energy (which makes them exergonic reactions)
Disassembling
a carbohydrate
Disassembling
a protein