1. The Chemical Building Blocks of Life
Chapter 3
Adapted by G. Cornwall, Ph.D.
From Raven’s Biology, McGraw Hill Publishing

2. Carbon
Framework of biological molecules consists primarily of carbon bonded to
Carbon
O, N, S, P or H
Can form up to 4 covalent bonds
Hydrocarbons – molecule consisting only of carbon and hydrogen
Nonpolar
Functional groups add chemical properties

3. Isomers Molecules with the same molecular or empirical formula
Structural isomers
Stereoisomers – differ in how groups attached
Enantiomers
mirror image molecules
chiral
D-sugars and L-amino acids

4. Macromolecules Polymer – built by linking monomers
Monomer – small, similar chemical subunits
Three things to keep track of in all four macromolecules
What is the Monomer
What is the Polymer
What is Bond

6. Dehydration synthesis
Formation of large molecules by the removal of water
Monomers are joined to form polymers
Hydrolysis
Breakdown of large molecules by the addition of water
Polymers are broken down to monomers

7. Carbohydrates Molecules with a 1:2:1 ratio of carbon, hydrogen, oxygen
Empirical formula (CH2O)n
C—H covalent bonds hold much energy
Carbohydrates are good energy storage molecules
Examples: sugars, starch, glucose

8. Monosaccharides Simplest carbohydrate
6 carbon sugars play important roles
Glucose C6H12O6

9. Fructose is a structural isomer of glucose
Galactose is a stereoisomer of glucose
Enzymes that act on different sugars can distinguish structural and stereoisomers of this basic six-carbon skeleton

10. Disaccharides
2 monosaccharides linked together by dehydration synthesis
Used for sugar transport or energy storage
Examples: sucrose, lactose, maltose

11. Polysaccharides Long chains of monosaccharides Energy storage
Linked through dehydration synthesis
Energy storage
Plants use starch
Animals use glycogen

12. Polysaccharides Structural support Plants use cellulose
Arthropods and fungi use chitin

13. Nucleic acids Polymer – nucleic acids Monomers – nucleotides
sugar + phosphate + nitrogenous base
sugar is deoxyribose in DNA or ribose in RNA

15. Nitrogenous bases include
Purines: adenine and guanine
Pyrimidines: thymine, cytosine, uracil
Nucleotides connected by phosphodiester bonds

17. Deoxyribonucleic acid (DNA)
Encodes information for amino acid sequence of proteins
Sequence of bases
Double helix – 2 polynucleotide strands connected by hydrogen bonds
Base-pairing rules
A with T (or U in RNA)
C with G

19. Ribonucleic acid (RNA)
RNA similar to DNA except
Contains ribose instead of deoxyribose
Contains uracil instead of thymine
Single polynucleotide strand
RNA uses information in DNA to specify sequence of amino acids in proteins

20. Other nucleotides ATP adenosine triphosphate NAD+ and FAD+
Primary energy currency of the cell
NAD+ and FAD+
Electron carriers for many cellular reactions

21. Card Quiz A The addition of water to break a chemical bond is termed –
Dehydration synthesis
Hydrolysis
Condensation
Disassociation
Bloom’s level: Knowledge/Understanding

22. Card Quiz A
The monomers of DNA are covalently bonded together. These bonds are called phosphodiester bonds.
This is true
This is false
Bloom’s level: Knowledge/Understanding

23. Card Quiz A Which of the following is not part of a nucleotide?
5 carbon sugar
Phosphate group
Fatty acid chain
Nitrogenous base
Bloom’s level: Knowledge/Understanding

24. Card Quiz A Dehydration synthesis – Is used to link monomers
Removes water to form bonds
Is involved in protein synthesis
All of the above
Bloom’s level: Application

25. Card Quiz A
If a strand of DNA has a sequence ATCCTAG, what would be the complementary sequence?
CGAAGAT
TAGGATC
TACCGGA
CGAAGTC
Bloom’s level: Application

26. Card Quiz Answers
Blue
Green
Red
Yellow
Bloom’s level: Application

27. Proteins
Protein functions include:

28. Amino acids are monomers Amino acid structure
Proteins are polymers
Composed of 1 or more long, unbranched chains
Each chain is a polypeptide
Amino acids are monomers
Amino acid structure
Central carbon atom
Amino group
Carboxyl group
Single hydrogen
Variable R group

30. Amino acids joined by dehydration synthesis
Peptide bond

31. Polypeptide chains fold in various ways to form the final 3-D shape
The shape of a protein determines its function

32. 4 Levels of protein structure
Primary structure – sequence of amino acids (beads on a string)

33. Secondary structure – interaction of groups in the peptide backbone
a helix
b sheet

34. Tertiary structure – final folded shape of a globular protein
Stabilized by a number of forces
Final level of structure for proteins consisting of only a single polypeptide chain

35. Quaternary structure – arrangement of individual chains (subunits) in a protein with 2 or more polypeptide chains

37. Additional structural characteristics
Motifs
Common elements of secondary structure seen in many polypeptides
Useful in determining the function of unknown proteins

38. Domains Functional units within a larger structure
Most proteins made of multiple domains that perform different parts of the protein’s function

39. Chaperones Once thought newly made proteins folded spontaneously
Chaperone proteins help protein fold correctly
Deficiencies in chaperone proteins implicated in certain diseases
Cystic fibrosis is a hereditary disorder
In some individuals, protein appears to have correct amino acid sequence but fails to fold

40. Denaturation Protein loses structure and function
Due to environmental conditions pH
Temperature
Ionic concentration of solution

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42. Lipids
Loosely defined group of molecules with one main chemical characteristic
They are insoluble in water
High proportion of nonpolar C—H bonds causes the molecule to be hydrophobic
Fats, oils, waxes, and even some vitamins

43. Fats Triglycerides Fatty acids
Composed of 1 glycerol and 3 fatty acids
Fatty acids
Need not be identical
Chain length varies
Saturated – no double bonds between carbon atoms
Higher melting point, animal origin
Unsaturated – 1 or more double bonds
Low melting point, plant origin
Trans fats produced industrially

45. Phospholipids Composed of Form all biological membranes Glycerol
2 fatty acids – nonpolar “tails”
A phosphate group – polar “head”
Form all biological membranes

46. Micelles – lipid molecules orient with polar (hydrophilic) head toward water and nonpolar (hydrophobic) tails away from water

47. Phospholipid bilayer – more complicated structure where 2 layers form
Hydrophilic heads point outward
Hydrophobic tails point inward toward each other

48. Other Kinds of Lipids

49. Card Quiz B What is the function of chaperonin proteins?
Denaturation of polypeptides
Assembling amino acids
Regulation of gene expression
Folding proteins
Bloom’s level: Knowledge/Understanding

50. Card Quiz B Which lipid forms membranes? Triglycerides Steroids
Phospholipids
Terpenes
Bloom’s level: Knowledge/Understanding

51. Card Quiz B Which of the following is not a function of proteins?
Catalyzes chemical reactions
Transport of material
Structural components of tissues
All of the above are protein functions
Bloom’s level: Knowledge/Understanding

52. Card Quiz B Which of the following is an amino group? -OH -C=O -COOH
-NH2
Bloom’s level: Knowledge/Understanding

53. Card Quiz B
Lincosamides are a class of antibiotics that inhibit peptide bond formation. What type of biological molecule would be effected?
Lipids
Proteins
Nucleic Acids
Carbohydrates
Bloom’s level: Application

54. Card Quiz B What happens when a lipid is hydrogenated?
Hydrogen is added to the fatty acid chains
The melting point is raised
The lipid is converted into a saturated fat
The fatty acid chain is straightened
All of the above
Bloom’s level: Application

55. Card Quiz Answers
Yellow
Red
Green
Bloom’s level: Application