Chapter 2 (Page 39-48) Lecture Notes
Carbohydrates: Sugars and Starches
Carbon, Hydrogen, Oxygen
“hydrated carbon”
Glucose: C6H12O6
Ribose: C5H10O5
Monosaccharides: Single Sugars (monomers)
Single Chain/Single Ring
Glucose: Blood Sugar- Universal cellular fuel
Fructose & Galactose: Converted to glucose for energy
Ribose & Deoxyribose: Part of the structure of nucleic acids
Disaccharides: Double Sugars
Formed when two simple sugars are joined by
dehydration synthesis.
Sucrose: Glucose+Fructose Table Sugar
Lactose: Glucose+Galactose Milk
Disaccharides are too large to pass through cell membranes
and must be broken down to simple sugars through the process
of hydrolysis.
Polysaccharides: “Many Sugars” (polymers)
Large insoluble molecules
Ideal way to store potential chemical energy
Starch: Energy storage polysaccharide formed by plants –
think grain products and root vegetables)
Cellulose: A more complex starch…largely indigestible
Glycogen: Found in animal tissues (muscles and liver)
Getting Energy from Carbohydrates:
Readily used source of food energy for cells. When glucose is
oxidized (combined with O2) it is broken in CO2 and H2O. The
energy released as the bonds are broken is stored in ATP
molecules (energy currency of body cells). If not needed
immediately for ATP synthesis the carbos are converted to
glycogen or fat and stored.
Lipids: Neutral Fats, Phospholipids, and Steroids
Enter the body as:
Fat-marbled meat
Egg Yolks
Milk Products
Oils
Lipids are also made up of Carbon, Hydrogen and Oxygen.
The carbon and hydrogen far out number oxygen
Insoluble in water, yet dissolve readily in other lipids and in
organic solvents i.e.: alcohol, ether, acetone
Neutral fats: also called Triglycerides
Structure: 3 fatty acids attached to a single glycerol
molecule
May be solid or liquid
Animal Fats = Saturated Fats (carbons have single bonds)
Plant Oils = Unsaturated Fats (carbons have some double or
triple bonds)
*Neutral fats are the bodies’ most abundant and concentrated
source of usable energy. When they are oxidized the yield
large amts. of energy. But, saturated (solid) fats tend to lead to
atherosclerosis and eventually to arteriosclerosis.
Phospholipids:
Structure: 2 fatty acids + glycerol+ phosphorus-containing
molecule
Phosphorus-containing portion bears a charge which attracts
and interacts with water and ions. The presence of
phospholipids in cell membranes allows cells to be selective
about what may enter or leave.
Steroids:
Flat molecules formed of 4 interlocking rings
Made largely of hydrogen and carbon atoms
Are fat soluble
Most important steroid in body is Cholesterol
Comes from meat, eggs, cheese and is also made by the liver..
It is the raw material used to form Vitamin D, some hormones
and bile salts.
High levels can lead to atherosclerosis and arteriosclerosis.
Proteins: Fibrous and Globular (polymers)
Account for over 50% of the organic matter in the body and
have the most varied functions of the organic molecules.
Construction materials
Vital roles in cell functions
*Carbon, hydrogen, oxygen, nitrogen and sometimes sulfur
atoms
Amino Acids: Building blocks of protein (monomers)
20 common varieties of AA’s
Amine group = gives them basic properties
Acid group = allows them to act as acids
R-group= group of atoms that make each AA chemically
unique
*Proteins contain AA groups in very large chains (thousands).
Fibrous Proteins: (Structural Proteins)
Appear in body structures
Bind structures together
Provide Strength in certain body tissues
Collagen- found in bones, cartilage and tendons
Keratin- Hair nails and skin
Globular Proteins: (functional proteins)
Mobile, generally spherical molecules
Crucial role in virtually all biological processes
Help provide immunity (antibodies)
Help regulate growth and Dev. (hormones)
Catalysts that regulate chemical reactions. (enzymes)
Can be denatured: When a globular proteins’ active site or
general structure is destroyed and they cannot perform their
roles.
Enzyme: Functional proteins that act as biological catalysts
Catalyst = substance that increases the rate of a chemical rxn.
without becoming part of the product or being changed itself.
Enzymes are capable of catalyzing millions of rxns. each
minute.
Enzymes are specific:
“hydrolases” add water
“oxydases” cause oxidation
“lactase” breaks down lactose
Nucleic Acids: DNA and RNA
Primary function is to store info. and to direct protein
manufacture.
NAs are polymers of nucleotide monomers which are
themselves made of a nitrogenous base, pentose, and a
phosphate group.
There are five nitrogenous bases: adenine, cytosine, guanine,
thymine, and uracil.
DNA: Double Helix of the nucleotides A, C, G, and T
Stores the code for the sequences of AA for various proteins.
Is copied before a cell divides.
RNA: Single Strand of the nucleotides A, C, G, and U.
Transfers the code in the DNA to the ribosomes.
Controls the assembly of proteins.
Adenosine Triphosphate (ATP): THE energy supplier in cells.
Cells need power to do transport, mechanical, and chemical
work.
Made from the catabolism of glucose
Structure includes adenine, ribose, and 3 phosphates.
Bonds between phosphates store the energy.
ATP  ADP + P + Energy
These four types of biological molecules compose all life on earth.
Proteins have an incredible variety of functions in living organisms. The functions of proteins include
but are not limited to: acting as biological catalysts, forming structural parts of organisms, participating
in cell signal and recognition factors and acting as molecules of immunity
Carbohydrates serve as the major source of energy for most living organisms. When simple sugars
combine to form polymers they can function as long term food storage molecules, as protective
coverings for cells and organisms, as the main structural support for land plants (cellulose) and
constituents of many cells and their contents.
Lipids are the major constituents of all membranes in all cells. They also serve as food storage
molecules. This class of biological molecules includes the hydrophobic fats, oils and waxes.
Nucleic Acids consist of two distinct, but closely related chemical forms: deoxyribonucleic acid (DNA)
and ribonucleic acid (RNA). The main functions of these biomolecules include the storage of all
heritable information of all organisms on earth and the use of this information to build proteins.
Often times students have difficulty remembering the four major classes of biological molecules, so I
have a way to help. To recall the four major classes of biological molecules I want you to think of lunch
at a hamburger joint. No endorsements intended! Take a hamburger, fries, and a milkshake and you
have all the components of the four major classes of biological molecules. Of all four classes which do
you think is most abundant in this meal?
If you guessed LIPIDS you would be right! The hamburger is full of fat, and processors add fat to the
hamburger bun. Mayonnaise is oil and egg yolk, which is mostly fat. Milk contains fat (if your shake
has any milk product in it), and fat is added to nondairy shakes. As for the fries, we all know why they
are called fries!
The hamburger bun is made from wheat flour, which is full of starch, a carbohydrate. The sugar in your
shake is the disaccharide sucrose, which is also a carbohydrate. As a matter of fact, the lettuce, onion
and tomato on that burger all contain cellulose, carbohydrate.
Meat is composed of muscle tissue, and muscle tissue is a
structural form of protein. Also most of the formerly living things
that we eat have some form of protein in them: wheat, milk,
potatoes, and so on.
All cells contain DNA and RNA (except mature mammalian red
blood cells) so DNA and RNA can be found in all organic matter.
The lettuce, onion, and tomato contain nucleic acid. The
hamburger meat contains cow DNA. The lettuce contains lettuce
DNA. The pickles contain cucumber DNA.
A burger, shake and fries is really just a pile of molecules of lipids
(fat and oils), carbohydrate (sugar and starch), protein (muscle)
and nucleic acids (DNA and RNA in the nuclei of cells
Calories per gram:
Fat – 9
Carbohydrate – 4
Protein – 4
16 Oz. Chocolate Shake
580
14
8
1
50
250
102
1
13
Big Mac
560
30
10
1.5
80
1010
47
3
25
Large French Fry
570
30
6
8
0
330
70
7
6
USRDA
2000
65
20
-
300
2400
300
25
-
43
66
73
44
% USRDA
86
114 120