1. Organic Molecules of Life

2. Organic molecules : are compounds created by living organisms
contain the elements carbon and hydrogen

3. Carbon atoms: need four electrons to fill their outer electron shell
Must form four bonds with other elements.
These are covalent bonds.
Most often bond with Hydrogen, Oxygen, Nitrogen, Phosphorus, Sulfur, and other Carbon atoms
6 P
6 N

4. These can include: Single bonds (one electron shared) Double bonds
(two electrons shared)
Or triple bonds
(three electrons shared)

5. Carbon Atoms: Can bond with other atoms of carbon to form long chains
These chains can be:
Straight
Branched
Rings

6. Isomers Molecules with the same formula Atoms are arranged differently
Carbons are branched in various ways

7. Functional groups:
Are special groups of atoms that stay together and act as a single unit
can bond with the carbon chains
determine how the entire molecule will react.

8. The functional groups you need to know are:

9. Hydroxyl Group one oxygen and one hydrogen usually written as -OH

10. Carboxyl Group
one carbon with a double bond to an oxygen AND a single bond to a hydroxyl group
usually written as COOH or
O=C–OH
Creates an organic acid (carboxylic)
Oxygen
Carbon
Oxygen
Hydrogen

11. Amino Group one nitrogen bonded to two hydrogen
usually written as NH2 or
H–N–H
Hydrogen
Nitrogen
Hydrogen

12. Phosphate Group:
One phosphorus bonded to two hydroxyl groups, and two other oxygens (one has a double bond)
Usually written as –P or OH
O P O
Phosphorus

13. Biological molecules can be made up of thousands of atoms

14. These large molecules are built from basic units called
monomers.
One monomer

15. The monomers are linked together to form the large molecules called
polymers.
Polymer – chain of repeating monomer units

16. Making and Breaking Polymer Bonds
Monomers
When two monomers are put together to form larger molecules, a water molecule is created.
Polymer

17. This process is called:
Dehydration Synthesis.
(Dehydration means to lose water Synthesis means to build or put things together)

18. When polymers are broken apart, it is done by adding a water molecule.

19. (hydro- for water, -lysis for breaking apart)
This is called
Hydrolysis
(hydro- for water, lysis for breaking apart)

20. Types of Organic Molecules
There are four categories of organic molecules in organisms:
Carbohydrates
Lipids
Proteins
Nucleic acids

21. Carbohydrates

22. What are Carbohydrates?
Organic compounds
Commonly called starches and sugars
Used as:
An energy source
Energy storage
Cellular structures

23. Chemical Composition Contains only three elements:
Carbon
Hydrogen
Oxygen
Ratio of hydrogen to oxygen is 2: (just like water)
Example: C6H12O6
Basic Unit is called a saccharide

24. Types of Carbohydrates
Monosaccharides
Simple, single (mono-) sugar unit
Building block of all other carbohydrates
Name usually ends in –ose
Used as energy source

25. Examples of Monosaccharides
Glucose – blood sugar
Fructose – fruit sugar
Galactose – one monomer in lactose (milk)
Isomers of C6H12O6

26. Examples of Monosaccharides
Ribose and Deoxyribose
5 - Carbon sugars in RNA and DNA

27. Types of Carbohydrates
Disaccharides
Double sugar units synthesized from monosaccharides
All are isomers of C12H22O11
Formed by dehydration synthesis (requires enzymes)

28. Examples of Disaccharides
Sucrose – table sugar
Glucose + Fructose
Maltose – seed sugar
Glucose + Glucose
Lactose – milk sugar
Glucose + Galactose

29. Types of Carbohydrates
Polysaccharides
Large, complex chains of many (poly-) repeating sugar units
Polymers
Bonded together by dehydration synthesis
Used by living things as a sugar storage or for structures

30. Examples of Polysaccharides
Amylose – plant starch
Used as sugar storage in seeds, roots, stems
Glycogen – animal starch
Used as sugar storage by humans in the liver
Cellulose
Very tough polymer
Used as a main component of cell walls
Indigestible by humans
Chitin
Used in exoskeletons (crab shells, insects)

31. Digesting Polysaccharides
Broken apart by hydrolysis with the help of enzymes

32. Lipids

33. What are Lipids? Three elements: Carbon Hydrogen Oxygen
Ratio of H:O much greater than 2:1
Example: Oleic acid C18H34O3
Insoluble in water
Greasy, slippery texture
Three main groups:
Fats oils and waxes
At room temperature: Liquid – oils/Solid – fats and waxes
Phospholipids
Steroids

34. What are the Functions of Lipids?
Fats, Oils and Waxes:
Long term energy storage
More than twice as much energy stored than carbohydrates
fats- 9 Calories/gram; carbohydrates- 4 Cal/g
In plants: stored in and around seeds
Peanut oil, corn oil, olive oil
In animals: stored under the skin and around internal organs
Used as insulation and shock absorber

35. What are the Functions of Lipids?
Phospholipids
Structural Part of Cell membranes
Steroids
Part of cell membranes, transport of lipids, regulate body functions (hormones)

36. Chemical Composition Fats Oils, Waxes
Fatty Acid
Glycerol
One or more fatty acids attached to a Glycerol backbone
Fatty Acids: Long chains of carbon with a carboxyl group at the end
Glycerol: C3H8O3
Formed by dehydration synthesis
NOT a polymer
Glycerol
Lipid

37. Formation of a Triglyceride:

38. Types of Fats Saturated
All carbons of the fatty acid have single bonds
All carbons are “filled” with hydrogen
Solid at room temperature
Associated with heart disease risk
Examples: Bacon grease, butter

39. Types of Fats Unsaturated
Carbons share one or more double or triple bonds with other carbons
Monounsaturated – only one double bond
Polyunsaturated – many double or triple bonds
Liquid at room temperature
Examples: corn oil, olive oil

40. Phospholipids Phosphate group replaces fatty acid on one end
Used as the main component of cellular membranes

42. Steroids: Four Fused Rings
lipids with four fused hydrocarbon rings
Includes:
Cholesterol - found in animal cell membranes
Testosterone, estrogen, progesterone - sex hormones
Vitamin D
An anabolic steroid is a synthetic testosterone.

43. Proteins

44. Protein Functions Structural parts Carriers Regulators
cell membrane, muscles, hair, nails, pigments
Regulators
Hormones, enzymes
Carriers
Transport materials in, out and around cells
Identification
Allow cells to recognize each other
Immune system antibodies

45. Composition of Proteins
Elements:
carbon, hydrogen, oxygen and NITROGEN
Very large, complex
Hemoglobin: C3032H4816O872N780S8Fe4
Monomers (building blocks) are amino acids
20 common amino acids
9 are essential 11 are non essential

46. The R group is different for each of the twenty amino acids

47. Peptide Bonds Chains of amino acids are called peptides
Amino acids are joined by dehydration synthesis
This occurs between the carboxyl end of one amino acid and the amino end of another amino acid.
The resulting bond is called a Peptide bond

48. Primary Structure
The sequence of amino acids in a protein is called the Primary Structure
The sequence is unique for each protein and is determined by the DNA

49. Secondary Structure
Hydrogen bonds are formed between the chains of amino acids causing different shapes.

50. Secondary Structure Two shapes are common – a helix and a sheet.
Sheet and Helix

51. Tertiary Structure
The 3-D arrangement of the molecule caused by weak bonds between the R groups
The most important structure format
Determines the function of the protein

52. Quaternary Structure
More than one protein molecule can combine to create a macromolecule
This is the quaternary structure of the protein
This creates either globular (hemoglobin) or fibrous (collagen) proteins

53. Nucleic Acids

54. Nucleic Acids are: The largest molecules in living things
The DNA of humans has about 6 billion monomers
Some reptiles have 20 times more units
The largest DNA known is a flower with 5 trillion units

55. The two most important Nucleic Acids:
DNA (deoxyribonucleic acid)
RNA (ribonucleic acid)

56. Functions of Nucleic Acids
DNA
make up chromosomes and their genes that carry hereditary information
found in the nucleus, mitochondria and chloroplasts (plants)
RNA
functions in the synthesis of proteins for the cell
found in cell parts: nucleoli, ribosomes, and throughout the cytoplasm

57. General Structure of Nucleic Acids
Polymers, with many repeating units called nucleotides
Nucleotides have three subunits:
a five carbon sugar
a phosphate group
a nitrogenous base
(a base that contains nitrogen)
Phosphate group
Nitrogenous Base
Five Carbon Sugar

58. Structure of DNA
The sugar backbone is deoxyribose

59. Structure of DNA The base can be one of four: Adenine Guanine Thymine
Cytosine

60. Structure of DNA The bases pair up –
A (adenine) always pairs with T (thymine)
G (guanine) always pairs with C (cytosine)

61. Structure of DNA

62. Structure of DNA
Two polymer chains of nucleotides are connected by weak hydrogen bonds and are twisted into a double helix

63. Structure of DNA
Sequence of nitrogenous bases codes for specific amino acids
Amino acid sequence determines the protein made in the cell and the cellular activity

64. Relationship Between Proteins and Nucleic Acids

65. Structure of RNA
Ribose is its sugar backbone

66. Structure of RNA The base can be one of four: Adenine Guanine Cytosine
Uracil
Thymine is replaced by Uracil

67. Structure of RNA
Only a single polymer chain is created in RNA, but strands of RNA have complex, folded structures that compliment their function.

68. Enzymes

69. What are Enzymes? Large, Complex Proteins
Function as Organic Catalysts
Allow reactions to occur at lower temperatures ( 37° C)
Used temporarily
Unchanged by the reaction
Can be reused
Specific to one reaction

70. What are Enzymes? Bind to reactants called substrates
Enzyme names usually end in –ase and can be named for their substrate:
Protease – proteins
Lipase – lipids
Maltase – maltose
ATPase – ATP
Acetylcholinesterase - acetylcholine

71. How Do Enzymes Work?
Reduces energy needed to begin reaction (Activation energy)
Without catalyst
With catalyst
Activation Energy
Energy
Energy
Time
Time

72. How Do Enzymes Work? Lock and Key Model Products Substrate Active Site
Substrate attaches to enzyme at active site
Enzyme Substrate Complex Formed
Reaction takes place and products are released

73. How Do Enzymes Work? Induced Fit Model Product
Enzyme substrate complex formed
Substrate
Enzyme
Enzyme
Enzyme
Substrate attaches to active site
Enzyme changes shape to match substrate –
Stressed molecule may help to weaken bonds
Enzyme resumes original shape after product formed

74. How Do Enzymes Work? Coenzymes sometimes needed
Non proteins – minerals, vitamins
Smaller molecules
Part of the enzyme structure or work along side the enzyme
Enzyme and substrate do not match
Coenzyme fills in needed shape
Coenzyme

75. Denaturation:
If the shape changes, the enzyme cannot function properly

76. Factors Affecting Enzymes
Temperature
Enzyme activity increases with temperature
Optimum temperature for each enzyme
Higher temperatures denature (change the shape) of the enzyme’s active site
Rate of reaction decreases quickly after optimum temperature
Optimum temperature

77. Factors Affecting EnzymespH
Enzymes are pH dependent
Some work at low pH (acid) Some at high pH (basic)
Surrounding solutions will activate or deactivate enzyme by changing the shape of the active site
Extremely high or low pH values generally result in complete loss of activity for most enzymes
pH for Optimum Activity
Enzyme
pH Optimum
Lipase (pancreas)
8.0
Lipase (stomach)
Lipase (castor oil)
4.7
Pepsin
Trypsin
Urease
7.0
Invertase
4.5
Maltase
Amylase (pancreas)
Amylase (malt)
Catalase

78. Factors Affecting Enzymes
Concentration:
Increasing amount of enzyme:
rate increases then levels off
substrate levels fall and reduces efficiency
Increasing amount of substrate:
enzyme is saturated and no additional reactions can occur
Presence of Inhibitors
Bind to enzyme and change shape or compete with the substrate