1. Part I – Introduction; Carbohydrates; Lipids
The Molecules of Cells
Part I – Introduction; Carbohydrates; Lipids

2. Organic Chemistry Study of carbon compounds
Occur in more than just living things
Are typically made by living things
Organic compounds come from organisms
The chemistry that you study in HS is inorganic
Compounds that are found in the non-living world

3. Organic Compounds
The molecules of many organic compounds are large and may seem complex, but they are built up using small and relatively simple subunits
YOU MUST BE ABLE TO IDENTIFY THESE STRUCTURES, you do not have to be able to draw them.
Fatty Acid

4. Organic Compounds
Compounds containing carbon that occur in living organisms are regarded as organic.
Exceptions: carbonates and oxides of carbon (e.g. CO2)

5. A carbon atom has 4 valence electrons
Each valence electron can join with an electron from another atom to form a strong covalent bond.
Therefore, one carbon can form bonds with up to four other atoms.

6. Examples of carbon bonding to itself and to other atoms

7. Carbon can also form double and triple bonds
Two atoms share two pairs of electrons (double bond) or three pairs of electrons (triple bond)

8. Chains Rings Various 3-D Shapes
The molecules formed when carbon bonds with itself and other atoms can be in the form of:
Chains
Rings
Various 3-D Shapes

9. Carbon Skeletons Isomers have the same molecular formula Vary in
Isomers varying in their structures
Have different properties
Vary in
Length
Branching
Double bonds
Rings

10. small organic molecules  larger organic molecules
From Monomers to Polymers
small organic molecules  larger organic molecules

11. Molecular Diversity and Complexity of Living Organisms Results from:
variation in types of carbon skeletons that are possible
diversity of atoms of other elements that can be bonded to the skeletons at available sites

12. Important Concepts
Almost the entire dry weight of living organisms is composed of extremely large organic molecules (organic macromolecules).
Organic macromolecules are synthesized from simple subunits.
Organic macromolecules have many diverse structures and functions.

13. Major molecular components of an E. coli cell
Component Percentage weight
Water 70
Nucleic Acids 7
Protein 15
Carbohydrate 3
Lipid
Building Blocks
and intermediates 2
Organic Ions
Organic Macromolecules
27%

14. Macromolecules Synthesized from smaller subunits or building blocks
building block = monomer
macromolecule = polymer

15. Formation and Breakdown of Organic Macromolecules
Condensation
Joins monomers to form polymers - water is removed
Hydrolysis
Breaks down polymers to form monomers – water is added

16. Condensation Reactions
In a condensation reaction, 2 molecules are joined together to form a larger molecule
Water is also formed in the reaction
For example, 2 amino acids can be joined together to form a dipeptide by a condensation reaction
The new bond formed is a peptide linkage
Further condensation reactions can link amino acids to either end of the dipeptide, eventually forming a chain of many amino acids
This is called a polypeptide
Condensation Reactions
activity 5.1 page 2

17. Condensation Reactions
In a similar way, condensation reactions can be used to build up carbohydrates and lipids
The basic subunits of carbohydrates are monosaccharides
2 monosaccharides can be linked to form a disaccharide and more monosaccharides can be linked to a disaccharide to form a large molecule a polysaccharide

18. Macromolecule FORMED by CONDENSATION
BROKEN BACK DOWN into subunits by HYDROLYSIS

19. three fatty-acid tails
glycerol
triglyceride
+ 3H20
Fatty acids can be linked to glycerol by condensation reactions to produce lipids called glycerides
A max of 3 fatty acids can be linked to each glycerol, producing a triglyceride

20. Hydrolysis Reactions
Large molecules such as polypeptides, polysaccharides and triglycerides can be broken down into smaller molecules by hydrolysis
Polypeptides + water  dipeptides or amino acids
Polysaccharides + water  disaccharides or monosaccharides
Glycerides + water  Fatty acids + glycerol

21. Classes of Organic Macromolecules in Cells
Carbohydrates
Lipids
Proteins
Nucleic Acids

22. Carbohydrates
Building blocks (monomers) are simple sugars called monosaccharides.
Function in energy storage and cell structure

23. Glucose – a common monosaccharide

24. Galactose – another common monosaccharide

25. Fructose – a third type of monosaccharide

26. Monosaccharides Examples
glucose
ribose
deoxyribose
fructose
galactose

27. Carbohydrate Polymer Synthesis and Breakdown

28. Three examples of disaccharides – maltose, lactose, and sucrose
The disaccharide (two monosaccharides linked) is the beginning of a carbohydrate polymer.
A carbohydrate polymer with more than two monosaccharides is a polysaccharide.

29. COMPONENT MONOSACCHARIDES
Disaccharides
COMPONENT MONOSACCHARIDES
DISACCHARIDE
DESCRIPTION
SUCROSE COMMON TABLE SUGAR GLU + FRU
LACTOSE MAIN SUGAR IN MILK GALACTOSE + GLU
MALTOSE PRODUCT OF STARCH HYDROLYSIS GLU + GLU
CAN BE USED IN BEER FERMENTATION

30. First example of polysaccharide - cellulose

31. Second example of polysaccharide - starch

32. Third example of polysaccharide - glycogen

33. Some functions of carbohydrates in animals
Glucose: broken down in cellular respiration to release energy
Lactose: the sugar in the milk produced by mammals
Glycogen: energy store in liver and skeletal muscles

34. Some functions of carbohydrates in plants
Fructose: energy source and component of sucrose
Sucrose: unreactive, and so a good way to transport sugar throughout the plant
Cellulose: main component of the cell wall

35. Starch repeating, branching macromolecule carb storage for plants
For energy
Cellulose

37. Glycogen storage of glucose in the liver and muscle animals only
For energy
animals only

38. Chitin
forms exoskeleton of arthropods: insects, lobsters, shrimp, spiders

39. Polysaccharide Description Monomer Unit
POLYSACCHARIDES
Polysaccharide Description Monomer Unit
STARCH energy storage in plants α-glucose
CELLULOSE structure of plant cell walls β-glucose
GLYCOGEN energy storage in animals α-glucose
CHITIN structure of fungi cell walls & β-glucose exoskeleton of insects