1. The Molecules of Cells… dun
dun dahhhhh – ch 3
Organic chem -
Carbon – most versatile building block –
why?
Tetravalence –
Where does the C in your body come from?

2. Valences of common atoms in orgs
What is the bonding capacity of H?
What is the bonding capacity of O?
What is the bonding capacity of N?
What is the bonding capacity of C?

3. Which of these would be
improperly bonded?

4. Variation in C skeletons contributes to
diversity of organic molecules
Straight, branched, closed rings, some have double bonds, triple

5. Isomers
• molecules w/ same molecular formula (same number and
kinds of atoms) but diff atom arrangements (which atoms
are attached to which and how)
Classes of isomers: structural, geometric, enantiomers

7. Geometric isomers = share same covalent partnerships, but
differ in their spatial arrangements.
• Result from fact that double bonds will not allow the atoms
they join to rotate freely about the axis of the bonds.
• Subtle differences affects biological activity.

8. • Enantiomers = mirror images of each other.
• Can occur when 4 diff atoms or groups of atoms are bonded
to the same carbon (asymmetric carbon).
• 2 diff spatial arrangements of the four groups around the
asymmetric carbon. These arrangements are mirror images.
• Usually one form is biologically active and its mirror image is
not.

9. How many asymmetric carbons are present?

10. Functional Groups
• contribute to molecular
diversity of life
• frequently bonded to carbon
skeleton of organic molecules.
• Have specific chemical and
physical properties.
• Are the regions of organic
molecules which are commonly
chemically reactive.
• Behave consistently from one
organic molecule to another.
• Depending upon their number
and arrangement, determine
unique chemical properties of
organic molecules in which
they occur.

11. Hydroxyl
- OH
• polar group
• Conveys water solubility
• Organic compounds with hydroxyl groups are called alcohols.

12. Carbonyl Group
-C=O
• polar group
• Conveys water solubility.
• found in sugars.
• at the end of skeleton called aldehyde.
• at the middle of skeleton called ketone

13. Carboxyl Group
• polar group
• Conveys water solubility
• Since it donates protons, has acidic properties.
• Compounds w/ this group are called carboxylic acids.

14. Amino Group
• polar group
• Conveys water solubility
• Acts as weak base. The unshared pair of electrons on the
nitrogen can accept a proton, giving it a +1 charge.
• Organic compounds w/ this group are called amines.

15. Sulfhydryl Group
• Help stabilize the structure of proteins.
• Organic compounds with this functional group are called
thiols.
What other functional groups do you see in this
molecule?
Could this molecule have an enantiomer isomer?
How do you know?

16. Phosphate Group
• Loss of two protons leaves phosphate group w/ a - charge.
• Has acid properties since it loses protons.
• Polar group
• Conveys water solubility
• Important in cellular energy storage & transfer

17. Methyl Group
• Non polar
• Conveys hydrophobic properties

18. Macromolecules,
baby!
Carbs
Lipids
Proteins
Nucleic acids

19. Some basics
Polymer – long molecule consisting of many similar or
identical building blocks linked by covalent bonds
Monomer -

20. How do the bonds b/t monomers form?
Condensation rx or dehydration synthesis – removal of water
from monomers
Facilitated by enzymes – speed up the rx

21. How do the bonds b/t monomers break?
Hydrolysis – bonds broken by addition of water
Hydro = water
Lysis = break
Ex: digestion
Enzymes facilitate

22. Diversity of macromolecules
26 letters make many words
40-50 monomers make many macromolecules
Key is in arrangement of monomers
Tac Act Cat

23. Carbohydrates
• Function – fuel & building mat.
• Sugars & their polymers
• simplest are monosaccharides or simple sugars.
• Disaccharides (double sugars) consist of 2 monosaccharides joined by
condensation reaction.
• Polysaccharides - polymers of many monosaccharides.

24. monosaccharides
• some multiple of the unit CH2O.
• Ex: glucose = C6H12O6.
• Funcitonal groups: carbonyl group (>C=O) and multiple hydroxyl groups
(—OH).
• names end in -ose.
•

25. Diversity of monosaccharides
• classified by # of carbon atoms in skeleton (3-7)
• Some are enantiomers of each other - spatial arrangement
of their parts around asymmetric C atoms.
Structural isomers enantiomers

26. Monosaccharides cont…
• most form rings in aqueous solutions.
• major nutrients for cellular work.

27. Disaccharides
• glycosidic linkage to form a disaccharide via dehydration.
• Maltose - joining 2 glucose
• Sucros- joining glucose & fructose.
• Lactose - joining glucose & galactose.

28. Polysaccharides - storage
• Function in storage & structural roles.
• 100s – 1000s of monosaccharides joined
• Starch - plant storage polysac composed entirely of glucose
monomers.
• Plants store surplus glucose as starch granules within plastids, including
chloroplasts & withdraw as needed for E or C.
• Glycogen – animal storage polysac. Store 1 day supply in liver &
muscles

29. Polysaccharides - structural
• Cellulose – plant structural polysac - major component of cell walls
– most abundant organic compound on Earth.
– Like starch, cellulose is polymer of glucose. However, the glycosidic linkages
in these two polymers differ.
– Digestion... Symbiotic orgs
• Chitin – animal structural polysac - found in the exoskeletons of arthropods
– also provides structural support for cell walls of fungi.

30. Lipids
• Consist mostly of hydrocarbon
• Little – no affinity for H2O (water insoluble)
• Not polymers
• 3 families
– Fats
– Phospholipids
– Steroids

31. Fats
• Glycerol & & fatty acid
• Dehydration synthesis
• Linkage – ester
• Vary in length & the # & location of double bonds
• Functions:
– E storage
– Cushions organs
– Insulates body

33. 2 main types of fats
1. Saturated – saturated w/ H; no double bonds
– Animal fats
– Solid @ room temp… why?
– Contribute to arteriosclerosis
Yum
!

35. 2 main types of fats
2. Unsaturated – not saturated w/ H; has double bonds
Creates kink in shape @ double bond
Liquid @ room temp
Plants & fish
Peanut butter? Why solid?

36. Phospholipids
• 1 glycerol
• 2 fatty acids
• 1 phosphate group

37. Phospholipids
• Amphipathic
• Major component of cell membranes
• Structure determines function

38. Steroids
• C skeleton consisting of 4 interconnected rings.
• Vary based on functional groups
• Cholesterol – imp. In membranes of animal cells
– Most other steroids made from it

39. Proteins!
• large
• funcitons:
– Structure (silk)
– Storage (casein)
– Movement (actin & myosin)
– Defense (antibodies)
– Regulation of metabolism
(enzymes)
– Transport (hemoglobin)
– Communication (hormones)
– receptor proteins

40. basics
• Monomer – amino
acids (20 diff)
– Vary based on R
groups
– Structure of aa
– Linkage –
peptide bond
– Backbone
– Aka polypeptide

41. Condensation
reaction or
dehydration
synthesis

43. Conformation = 3 D shape of a
protein molecule
Shape determines function
DNA codes for the type of aa & what order they’re
bonded in
So…
DNA codes for which proteins you make & which
proteins you make determines your physical
characteristics

44. Proteins are so
complex that we
describe their
structure on 4 levels
1. Primary structure
• the seq of aa
• Det by DNA
• Sanger, insulin

45. Notice primary structure & backbone

46. Proteins are so complex
that we describe their
structure on 4 levels
2) Secondary structure
• Pattern of folds & coils
that result from the
H-bonding at regular
intervals along the
polypeptide backbone.
• 2 types: alpha helix &
pleated sheet

48. Proteins are so complex
that we describe their
structure on 4 levels
3) Tertiary structure
• Irregular contortions
that result from
bonding b/t R groups
of the aa
• Types of bonds that
can occur b/t R
groups:
– H-bonds, disulfide
bridges, ionic,
hydrophobic
interactions

49. Proteins are so
complex that we
describe their
structure on 4
levels
4) Quaternary
structure
• Only those
composed of 2 or
more polypeptide
chains
• Overall structure
that results from
the aggregation of
polypeptide chains

50. Emergent property?
Specific function of a protein arises from the
architecture of the molecule

51. Denaturation?
• Loss of conformation of a protein
• Causes? High temps, change in salt concentration, change
in pH

52. Review of levels

53. Nucleic Acids
•Deoxyribonucleic acid (DNA) & RNA
•Double helix
•Watson and Crick—1953
•Made of smaller molecules called
nucleotides bonded together

54. Relationship
between DNA
&
chromosomes?
Chromosomes
are made of
DNA!

55. Monomers are nucleotides
5 Different ones
• Deoxyribose: sugar molecule
• Phospahte group: a phosphorus atom surrounded by oxygen
• Nitrogen containing base: molecule containing nitrogen
adenine (A)
guanine (G)
cytosine (C)
thymine (T)

56. Dehydration synthesis & then H-bonds
b/t N bases

57. Complementary Base
Pairing
• Cytosine - Guanine
• Adenine - Thymine
• Connected by H-bonds
• Allows DNA to make exact
copies of itself

58. DNA REPLICATION
http://www.lewport.wnyric.org/jwanamaker/animations/DNA%20Repl
ication%20-%20long%20.html

59. Complementary Base Pairs
• TTACGGCAT base pair would be????

61. DNA &
RNA

62. DNA & RNA Compared
DNA RNA
Sugar deoxyribose ribose
Strands double single
Bases A,G,C,T A,G,C,U
(uracil)

63. Notice the
difference
between
the 2
sugars?
Sugar in DNA
Sugar in RNA

64. How is DNA the code for life?
• Gene – portion of DNA that codes for the making
of polypeptide (protein)
• What makes you unique is all the particular
proteins you make.