2.3 Carbon-based Molecules
Key Concept: Carbon-based molecules are the basis of life.
CHONPS!
 Cells are composed mostly of Carbon, Hydrogen,
Oxygen, Nitrogen, Phosphorus, Sulfur
Carbon atoms have unique
bonding properties.
 Carbon forms covalent bonds (strong bonds) with up to
four other atoms, including other carbon atoms
 Carbon-based molecules have three general types of
structures
 Straight chain
 Branched chain
 Ring
(form 3-D structures)
Carbon atoms have unique
bonding properties.
 Carbon can form single, double, or triple bonds
 Carbon forms isomers
 Isomers are compounds that have the same chemical
formula, but different structural formulas
 Example: C4H10
 Only carbon has these characteristics
STOP & REVIEW
 What four properties of carbon make it so special and
unique?
1. Carbon can form covalent bonds with up to 4 other
atoms. (This allows it to form huge macromolecules)
Macro = large
2. Carbon can have three shapes. (long chain, branch, or
ring)
3. Carbon can form single, double, or triple bonds.
4. Carbon can form isomers.
Many carbon-based molecules are made of
many small subunits bonded together.
 Monomers are the individual subunits.
 Polymers are made of many monomers.
Four main types of carbon-based
molecules are found in living things.
1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleic acids
Christina Likes Puppy Noses
Carbohydrates
Molecule 
Has Carbon
Carbohydrates
All of the time
Has Hydrogen
All of the time
Has Oxygen
All of the time
Has Nitrogen
-
Has Phosphorus
-
STRUCTURE
Monomer
Polymer
monosaccharide
disaccharide (dimer), polysaccharide
Examples
Monosaccharide: glucose (in your blood), fructose (fruit), galactose (milk)
Disaccharide: sucrose (table sugar), lactose (milk)
Polysaccharide: starch (structure: long chain of glucose molecules) &
cellulose (function: component of cell wall in plants),
glycogen (function: energy storage in animals)
Unique
-
- Function: Provide a quick source of energy
Structure: Usually found as rings, and branched chains
- Structure: 1:2:1 ratio of C:H:O
Lipids
Molecule 
Lipids
Has Carbon
All of the time
Has Hydrogen
All of the time
Has Oxygen
All of the time
Has Nitrogen
Some of the time
Has Phosphorus
Some of the time
STRUCTURE
Monomer
glycerol & fatty acids (polar heads & fatty acid tails)
Polymer
Examples
Unique
triglycerides; phospholipids
-Function: Phospholipids make up all cell membranes (allow them to
be fluid-like, more heat = more flexibility in fluid)
-Fats, oils, cholesterol, steroids, waxes, phospholipids
- Nonpolar
- Function: Long chains that are broken down to provide energy,
long term storage of energy
- Function: Used to make steroid hormones (control stress,
estrogen, testosterone)
- Structure: Fats and oils contain fatty acids bonded to glycerol
Saturated vs. Unsaturated Lipids
 Saturated fats:
 Structure: all bonds are full with hydrogens attached. Are
usually solid at room temperature, and most come from
animal products. Sometimes linked to circulatory (heart)
disease
 Unsaturated fats:
 Have double bonds, and are not full. Are liquid at room
temperature, and are usually referred to as oils.
Proteins
Molecule 
Has Carbon
Has Hydrogen
Has Oxygen
Has Nitrogen
Has Phosphorus
STRUCTURE
Monomer
Polymer
Examples
Proteins
All of the time
All of the time
All of the time
All of the time
-
Amino acid (there are 20 different kinds)
Polypeptide (protein)
Functions: Enzymes (speed up chemical reactions by decreasing
activation energy, hemoglobin (transport protein in blood), collagen
(structural protein part of connective tissue, which is used for movement)
An antibody, also known as an immunoglobulin, is a large Y-shape
protein produced by plasma cells that is used by the immune system to
identify and neutralize foreign objects such as bacteria and viruses.
Unique
-
- Structure: 3D structure makes them active
- Structure: Peptide bonds hold amino acids together
Structure: Have a side group (R) that makes each amino acid
(and therefore protein) different, make polypeptide chains
- Structure: Sometimes may contain sulfur
Different Shapes of a Protein
http://www.youtube.com/watch?v=lijQ3a8yUYQ
Nucleic acids
Molecule 
Has Carbon
Nucleic acids
All of the time
Has Hydrogen
All of the time
Has Oxygen
All of the time
Has Nitrogen
All of the time
Has Phosphorus
All of the time
STRUCTURE
Monomer
Polymer
Nucleotide (5-carbon sugar, phosphate group, & base)
Nucleic acid
Examples
Unique
DNA & RNA
- Order of the bases makes every living thing unique
- Function: DNA stores genetic information in chains
- Function: RNA builds proteins
STOP & REVIEW
 What are the 4 carbon based macromolecules?
 1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic Acids
 What is similar among the 4 carbon based macromolecules?
 They all have CHO in them
 What is unique between the 4 macromolecules?
 Their shapes are different, their functions are different
 What is a monomer
 Individual subunits (Ex: glucose)
 What is a polymer?
 A bunch of monomers together (Ex: Starch)
TED Ed Video
 http://ed.ted.com/lessons/the-science-of-macaronisalad-what-s-in-a-molecule-josh-kurz
Building & Using Carbon-based
Molecules
 Building (process): dehydration synthesis
 Removal of water to make a new product (water is a
product)
 Turns monomers into polymers
 Using (process): hydrolysis
 Breaking apart by adding water (water is a reactant)
 Turns polymers into monomers
Dehydration Synthesis
 Two monomers need to join
 One monomer loses (-OH) and one loses (-H)
 The two monomers join and the (-OH) and (-H) join,
forming H2O
 monomer-OH + monomer-H  polymer + H2O
Hydrolysis
 A polymer needs to break apart (the carbs, proteins,
and lipids we ingest are too big for us to use)
 Water breaks apart into (-OH) and (-H) and splits the
polymer into monomers
 The (-OH) and (-H) bond to each monomer to make them
stable molecules
 polymer + H2O  monomer-OH + monomer-H
 http://www.youtube.com/watch?v=b7TdWLNhMtM