1. Building Complex Molecules That Comprise Living Things
Macromolecules
Building Complex Molecules That Comprise Living Things

2. Four types of organic macromolecules are important in living systems.
Comparison of Terms
Molecule
Two or more non-metal atoms joined by covalent bonds
Macromolecule
Large polymer made of repeating monomer units
Four types of organic macromolecules are important in living systems.

3. Macromolecules: Polymers Made of Repeating Monomers
Monomer Unit
Carbohydrates
Sugars
Proteins
Amino acids
Nucleic Acids
Nucleotides
Lipids
Do not form polymers

4. Organic Macromolecules Contain Carbon
Question: How many electrons does carbon need to fill its outer energy level?
Answer: Four
Each carbon atom can make four
covalent bonds with other types of
atoms or additional carbons.

6. Synthesis and Breakdown of Macromolecules
Dehydration Synthesis
Removal of water to join monomer units
Hydrolysis
Addition of OH and H groups of water to break a bond between monomers

7. Dehydration Synthesis / Hydrolysis

8. Carbohydrates: Structure
Simple
Monosaccharides= one sugar unit
Glucose = blood sugar
All cells use glucose for energy

9. Carbohydrates: Structure
Simple
Disaccharides = two sugar units
Oligosaccharides (“oligo-” means few or scant).
Several monosaccharides joined together.
Sucrose (table sugar) is disaccharide of one glucose and one fructose (Fig 3-1, p39).
Often combined with other molecules.
Many larger molecules have oligosaccharides attached for various purposes.
Sometimes used for cell ID.
The cell membrane has many proteins in it, some of which have attached oligosaccharides projecting away from the cell. Sometimes these are used as chemical labels for cell type.
CH2OH H HO OH O
Glucose
CH2OH H HO OH O
HOCH2 O
HOCH2 H
CH2OH HO
Fructose + HO H
Sucrose & Water

10. Carbohydrates: Structure
Simple
Disaccharides = two sugar units
Sucrose = glucose + fructose table sugar
Lactose = glucose + galactose milk sugar
Maltose = glucose + glucose seed sugar

11. Carbohydrates: Structure
Complex
Polysaccharides= many sugar units
Starch -- storage in plants
Glycogen -- storage in animals
Cellulose -- plant cell walls, indigestible
Chitin -- exoskeletons of insects, fungal cell walls

13. Chitin

14. Carbohydrates: Functions
Energy source
Structural component
Cell-cell communication

15. Carbohydrates: Dietary Recommendations
58% of calories from carbohydrates
No more than 10% of calories from simple, refined sugars
Emphasize
Complex Carbohydrates
Starch
Fiber (cellulose)
Naturally-occurring simple carbohydrates
Fructose from fruit
Lactose from milk

16. Macronutrients As Energy Sources

17. Applying Your Knowledge
Monosaccharide
Polysaccharide
Disacharide
Which molecule consists of two sugar units?
Which choice best describes glycogen?
Which type of molecule provides the basic energy for your cells?
Which type of molecule is found in milk?

18. Lipids: Structure Triglyceride—predominant form in diet
One molecule of glycerol
Three fatty acids

19. Lipids: Structure Types of Fatty Acids
Saturated – 2H per internal carbon
Unsaturated -- <2H per internal carbon one or more double bonds
Monounsaturated – one double bond
Polyunsaturated – more than one double bond

20. Triglyceride FormationH C OH O C H
Glycerol
Remove These Waters C O H
This shows how water is removed from three fatty acids and glycerol to make a fat and water. C OH O H C OH O H C OH O H C O H
Add 3 Fatty Acids
HOH
3 Waters

21. Which Is a Source of Unsaturated Fatty Acids?
Linseed Oil
Beef Fat

22. Lipids: Structure Phospholipid—component of cell membranes Hydrophilic
Polar Head
Glycerol
Fatty Acid Tails
Hydrophilic
Hydrophobic

23. Lipids: Structure Steroids Linked carbon rings Natural body components
Hormones
Cholesterol
Complex ring forms
Some hormones, especially those produced by the adrenal gland and sex hormones.
Cholesterol
Natural substance; not necessarily bad for you.
Found in membranes in between the fatty acid tails of phospholipids.
Athletes beware of androgenics!
Dangerous chemicals.
Please reconsider your value system if you use these.
If you use them, you WILL regret it!

24. Steroids
Cholesterol
Estradiol
Testosterone

25. Lipids: Functions Concentrated energy source
Structural components of cell membranes
Phospholipids
Cholesterol
Communication
Steroid Hormones
Protection from water
Waxes
Cholesterol
Phospholipids

26. Lipids: Dietary Recommendations
< 30% of calories from lipids
< 10% of calories from saturated fats
Limit cholesterol to 300 mg/day
Avoid “trans” fatty acids in partially hydrogenated products
Emphasize
Unsaturated fatty acids from vegetables, fish, legumes, and nuts
Oils: mono- or polyunsaturated

27. Macronutrients As Energy Sources

28. Applying Your Knowledge
Polyunsaturated fatty acid
Cholesterol
Monounsaturated fatty acid
Saturated fatty acid
Which molecule is made of a series of carbon rings?
Which molecule has more than one double bond?
Which molecule has 2H for each internal carbon?
Which molecule has one double bond?

29. Macromolecules: Polymers Made of Repeating Monomers
Monomer Unit
Protein
Amino acids

30. The “R” Group Differs for Each Amino Acid
Proteins: Structure
Primary structure = chain of amino acids
Amino acids have common features
Carboxylic Acid Group
Amino Group    
See p 34 R
“Alpha” Carbon
The “R” Group Differs for Each Amino Acid

31. Amino Acids: Phenylalanine Structure
Amino Group  
Carboxylic Acid      Group
“Alpha” Carbon
See p 34
Valine is still another of the 20 amino acids found in proteins.
The constant part for valine is the same as for glutamine and cysteine, and only the "R" group varies.
Phenylalanine “R” Group

32. Amino Acids: Leucine Structure
Amino Group  
Carboxylic Acid      Group
Leucine “R”      Group

33. Proteins: Structure Forming the Protein Chain
Phenylalanine
Leucine
Here we position two amino acids close together so that the amine group of one is close to the carboxyl group of the other.
Note that a -H is hanging out from one, and a -OH from the other.
These will be broken off (by an enzyme) to form water.
The remaining bonds of the two amino acids will be connected to form a dipeptide (two amino acids joined by a peptide linkage).
Dehydration Synthesis between COOH & NH2

34. Proteins: Structure Forming the Protein Chain
The Peptide Bond
Water
Phenylalanine-Leucine Dipeptide

35. Four Levels of Protein Structure
Primary (Sequence)
Tertiary (Folding by R-group interactions)
Depending on the sequence of amino acids, the polypeptide chain can either form a spiral like the tube on the left, or a pleated sheet like on the right.
Some proteins have a spiral section followed by a sheet section, etc.
Fig 2.26, p35.
Quaternary (Two or more chains associating)
Secondary (Coiling by Hydrogen Bonding)

36. Four Levels of Protein Structure
Primary Structure = sequence of amino acids in chain

37. Four Levels of Protein Structure
Secondary Structure
Folded structure due to hydrogen bonds between the amino and acid groups of amino acids N C N C H O H or O O H O H C N C N

38. Found in most proteins
Found in silk

39. Four Levels of Protein Structure
Tertiary Structure:
Three dimensional folded structure due to attractions and repulsions between R groups
Can involve
covalent bonding hydrogen bonding ionic interactions hydrophilic and hydrophobic interactions

41. Hair Curling Straight Hair Naturally Curly Hair | S | S | | S | S |

42. Four Levels of Protein Structure
Quaternary Structure:
Association of two or more protein chains
eg. Hemoglobin is composed of 4 protein chains
2 are called alpha hemoglobin
2 are called beta hemoglobin

43. Proteins: Functions Structural Component of Cells
Control of Metabolic Reactions: enzymes
Growth and Repair
Communication
Protein Hormones
Cell Receptors
Energy source
Protein
Protein

44. Proteins: Dietary Recommendations
12% of calories from proteins
8 essential amino acids obtained from
Lean sources of animal protein
Complementary plant proteins
Beans + Grains
Beans + Seeds

45. Applying Your Knowledge
Primary
Secondary
Tertiary
Quaternary
Which structure results from hydrogen bonding?
Which structure involves an association of two or more protein chains?
Which structure describes the linear sequence of amino acids?
Which structure depends upon interactions between the R groups of the amino acids?