Download Chapter 3 – sections 3

Chapter 3 – sections 3.1 to 3.3
Carbon based molecules are called ____organic (carbon/hydrogen)____________.
Carbon is ideal to make complex molecules because every carbon can form 4-bonds.
That means that carbon can form long chains, branched chains, or even rings. Many
molecules that make up our bodies consist of thousands of carbon atoms bonded together.
What kind of bond does carbon form?
Covalent – which are strong, sturdy bonds – Because they are stable bonds, they are
capable of storing energy – in other words it takes energy to build a bond and because of
the laws of thermodynamics, when that bond is broken it releases that energy back out. In
photosynthesis, plants can use energy from sunlight to make carbon bonds –animals eat
plant matter and can then break down those bonds to release that energy to do work.
Can carbon form multiple bonds (in other words – single, double, triple)? Give an
example of a double bond if you can find it.
Carbon can form multiple bonds. Saturated fats are triglycerides with fatty acid chains
consisting of all single bonds between the carbons – harder to digest. Unsaturated fats
have fatty acid chains with some double bonds and are easier to digest.
Define the following terms:
 Hydrocarbons – carbon and hydrogen molecules 
Carbon skeleton – the chain or rings made by interlocking carbons – other
functional groups and atoms can attach to the skeleton to give it specific
properties.

Isomers – alternate arrangements of the same atoms into different molecules.

Functional groups – groups of atoms that hang off the carbon skeleton and help
determine its properties -
Hydrocarbons are primarily carbon, hydrogen, and oxygen – what gives carbon
molecules their unique properties are the vast variety of functional groups that may be
attached to the carbon skeleton.
What does it mean when we say a functional group makes a molecule hydrophilic –
another polar molecule that can mix with water? Based on that definition, what do you
think it means to be hydrophobic – a nonpolar molecule that cannot mix with water???
Name of functional group
Hydroxyl
Description and common source
-OH found in carbohydrates and alcohol – critical part of
most organic molecules
Carbonyl
C=O found in simple sugars
Carboxyl
COOH – found in carbohydrates and amino acids
Amino groups
NH3 – defines amino acids
Phosphate
PO4 – found in nucleic acids, also critical to the high energy
molecule of ATP.
Define the terms:
 Macromolecules – BIG molecules – like proteins, complex carbohydrates, nucleic
acids

Monomer – single unit – building blocks of polymer – most macromolecules are
polymers made up of monomers – i.e. protein is a chain of amino acids.

Polymer – Chain of monomers – starch is a chain of simple sugars.

Dehydration reaction – many metabolic (anabolic – building) reactions are a
product of dehydration synthesis – one end of a monomer has an –OH and the
other end of another monomer has a –OH, the reaction involves hooking the two
monomers together by combining the OH and the H to make H2O and have
connected the two monomers together.

Hydrolysis – The reverse of the above – catabolic reaction – by adding water back
to units in a chain, the chain can be broken with an –OH going to one side and a –
H
Four types of organic macromolecules:
1. Carbohydrates – C, H, O – in animals it is used primarily for energy but in plants,
fungi, and some bacteria it is also used for structure. Simple sugars are the
monomers that hook together to make complex carbohydrates like starch,
cellulose, or glycogen.
2. Proteins – the monomers are amino acids which are hooked together to make
proteins. Proteins do all the work in the cell (they make enzymes) and they are
used structurally.
3. Lipids – all are characterized by being nonpolar or hydrophobic – includes fats
(triglycerides) and steroids and cholesterol. Fats are good energy storage but also
insulation and padding. Lipids are main component of cell membranes.
4. Nucleic acids – DNA is an example. The monomers are nucleotides which make
long chains that become DNA or RNA. The genetic code!!!
Study the diagram on page 36 and use that information to label the following two
reactions: