1. The Chemistry of Organic Molecules
Chapter 3

2. Organic Molecules
3.1

3. Organic Molecules
Organic Chemistry- the chemistry of living organisms.
Inorganic Chemistry- chemistry of nonliving matter.
Organic- molecules and compounds that contain both carbon and hydrogen atoms.
Four classes of organic molecules in living things:
Lipids
Carbohydrates
Proteins
Nucleic Acids

4. The Carbon Atom Six electrons
Always form covalent bonds (almost always)
C-C bond is so stable it allows the formation of long chains

5. The Carbon Atom
Carbons can also form a ring structure when placed in water environments.
Double bonds between carbons aren’t as flexible, restrict movement
Can also form triple bonds with itself.

6. Carbon Skeleton and Functional Groups
Carbon chains are called the skeleton or backbone.
Functional group- specific combination of atoms that always have same chemical properties regardless of carbon skeleton attached to it.

8. Isomers
Identical molecular formulas but different arrangements of atoms.

9. Biomolecules of Cells
Polymers- large number of the same subunit linked together (carbs, proteins, and nucleic acids)
Lipids are made of different subunits linked together so they are NOT polymers

10. Synthesis and Degradation
Build- dehydration reactions –OH AND –H groups are removed making water.
Break down- hydrolysis reactions –OH and –H are added
Enzymes that act as catalysts are usually needed for these to occur.

11. Carbohydrates
3.2

12. Carbohydrates Immediate energy source in living organisms. 1:2:1
Chain length varies.
Monosaccharides-monomer subunits
Polysaccharides- long chains of monosaccharides.

13. Monosaccharides Simple sugars Carbon backbone of 3 to 7 carbons
Pentose
Hexose
Glucose is a hexose monosaccharide
Ribose and deoxyribose are pentose ones

14. Disaccharides Two monosaccharides that have joined together.
We use sucrose to sweeten our food.
Lactose

15. Polysaccharides: Energy Storing Molecules
Monosaccharides linked together.
“Complex carbs”
Short-term energy storage because not as soluble in water and larger than simple sugars.
Can’t easily get through the plasma membrane
Plants- starch
Animals- glycogen

16. Polysaccharides: Structural Molecules
Plants- cellulose
Most abundant organic molecule on earth
Wood, cotton
animals/fungi- peptidoglycan
Chitin- found in exoskeleton of insects, lobsters, and crabs.

17. Lipids
3.3

18. Lipids Fats or triglycerides Insulation and long-term storage
In plants, they are referred to as oils.

19. Triglycerides Fatty acid Glycerol
Each has a long hydrocarbon chain with an EVEN number of carbons and a
–COOH
Saturated fatty acid- no double bonds
Unsaturated fatty acid- double bonds between C-C, melt faster
Trans fat is a triglyceride that has one bond in the trans configuration
Glycerol
3-C compound with three –OH groups
Soluble in water

21. Phospholipids
Triglycerides except in place of 3rd fatty acid, there is a polar phosphate group
Hydrophilic heads and hydrophobic tails

22. Steroids Lipid structures with skeleton of four fused carbon rings.
Cholesterol provides stability to cell membrane and is the precursor to other steroids.
Testosterone, estrogen, etc.

23. Proteins
3.4

24. Proteins 50% of the dry weight of most cells is protein.
Play a role in metabolism, support, transport, defense, regulation, and motion.
Hundreds of thousands proteins identified so far.

25. Amino Acids: Protein Monomers
Proteins are made up of aa.
20 aa total.

27. Amino Acids
Peptide Bond
When two or more amino acids are linked together it is called a peptide.
When many are linked together it is called a polypeptide.

28. Shape of Proteins Four levels of structural organization
Primary- linear sequence of aa
Secondary- polypeptide folds or curls
Tertiary- folding into three dimensional shape
Quaternary-more than one polypeptide

30. Nucleic Acids
3.5

31. Nucleic Acids
Polymers of nucleotides, store info, conduct chemical reactions.
DNA is one type of NA
Stores info
Specifies order of aa for proteins
RNA
mRNA is a copy of gene that specifies what aa sequence will be during the process of protein synthesis.
tRNA helps translate for protein
rRNA works as enzyme to form peptide bonds between aa in the polypeptide

32. Structure of DNA and RNA
Sugar
DNA-deoxyribose
RNA-ribose
Phosphate
Nitrogen containing base
DNA- A, T, G, C
RNA- A, U, G, C

33. ATP (Adenosine Triphosphate)
Adenine and ribose and three phosphates (3 P)
ADP- diphosphate (2 P)
Used for energy by the cell.