Unit 3: Biochemistry

Deer Park High School North
Biomolecules are organic molecules or carbon
compounds because they contain carbon.
They are known as organic because the
compose living things.
Organic = Living
Why is Carbon useful in forming living things?
 Because:
Carbon forms STRONG bonds.
Carbon can form 4 bonds – continuous chainswhich can form large compounds. (macromolecules)
Carbon WANTS to bond with 4 other atoms.
There are 4 major organic molecules:
◦ Carbohydrates (sugars) – main energy source for all
living things. (short energy storage)
◦ Proteins – make up the majority of our body; muscles,
hair, skin, nails, etc. (Do NOT produce energy.)
◦ Lipids – Fats; Build up membranes. (Long term energy
◦ Nucleic Acids – DNA which stores information and RNA
(“slave” to DNA) – major structures for hereditary
A MONOMER is a single organic molecule. These
are the building blocks of biomolecules.
“MONO” means one; a single object.
When we start putting monomers together, we
build a chain of monomers called a POLYMER.
“POLY” means many; many objects.
To create biomolecules, monomers must “link”
together to form chains, which become
polymers. These polymers have to be put
The process that builds monomers into
polymers is called Dehydration Synthesis.
= removing water
= to put together
How do we pull polymers apart or break them
Add water back into the polymer to break
apart the monomers back into single
The process used to break down large polymers
into smaller monomers is called HYDROLYSIS.
Hydro - To hydrate; add water
Lysis - To break apart or digest
Functional Groups give functionality, behavior
to the major organic molecules.
There are 6 functional groups:
1. Hydroxyl
2. Carboxyl
3. Amine
4. Methyl
5. Sulfudryl
6. Phosphate
Carbohydrates – Sugar molecules; Gives
energy and structure
The Structure of Carbohydrates
 Made up of carbon, hydrogen and oxygen. The
general formula is CH2O.
 Typically, the formula for a sugar molecule is generally
a 1:2:1 ratio.
Example: Common sugar, glucose, has the chemical
formula of C6H12O6. In the chemical formula, the 6:12:6
ratio reduces to a 1:2:1 ratio.
Functions of Carbohydrates
Primary Energy Source (Quick Energy). Very little
energy required to breakdown is the reason it’s used
first. (Examples: Glucose, Sucrose, Fructose,
Galactose, Ribose, deoxyribose.)
Energy Storage. [Examples: Starch (plants), Glycogen
(animals – muscle and liver)]
Structural. [Examples: Celluose (plant fiber), Chitin
(exoskeleton, cell walls in fungi)]
** Many carbohydrate names end in ose.
Produced by green plants in chloroplasts
undergoing Photosynthesis
IV. Monomers (building blocks)
Monosaccharides – simple sugars
V. Examples
1. Monosaccharides (“Mono” = One, “Saccharide” = Sugar)
Glucose (C6H12O6) – Blood sugar, used for cellular respiration
Fructose – found in fruit
Galactose – found in milk
Deoxyribose – used in DNA (5 Carbon sugar – missing one
Ribose – Used in RNA (5 Carbon Sugar)
Dehydration Synthesis joins two sugars
together by removing an OH from one sugar
and a H from the other to produce a new sugar
and a water molecule.
Disaccharides – (“Di” = Two, “Saccharide” = Sugar)
 Sucrose (C12H22O11) – Table Sugar (Glucose + Fructose)
 Lactose – Sugar found in milk (glucose + galactose)
 Maltose – Sugar found in germinating grain (glucose + glucose)
Let’s add one more sugar molecule to the disaccharide…Now we
have 3 molecules put together by pulling water molecules out. We
can do this over and over creating a polymer called a complex
carbohydrate or POLYSACCHARIDE.
How do we undo what we just built? …Just
reverse the process by adding water
molecules back in. The bonds would need to
be broken this time and OH and H are added
back in during the process of HYDROLYSIS
Hydro (water) + Lysis (to cut) = cutting with
3. Polysaccharides – (“Poly” = many; “Saccharide” = Sugar)
If we add more sugar molecules to a disaccharide, then we
will begin to have a long chain of sugar molecules that are bonded
through Dehydration Synthesis. This creates a POLYMER of sugars
which is a chain of many sugars that we call a COMPLEX
Starch (storage role) – bent chains: Hundreths of
glucose molecules are attached over and over
Why are plants doing it?
Why do plants make these large molecules?
◦ To store excess sugars!
Can we (Animals) do that?
Glycogen (storage role) – Chains are branched
Thousands of glucose molecules are broken
down into monosaccharides
them again and store a s glycogen in the
We can get to that storage when we need it!
Chop up those monosaccharides in order to
use them in our cells!
Cellulose (Structural role) – Straight chains
The structure of plants is made of cellulose.
Major component of the plants’ cell wall;
commonly known as fiber (roughage).
They form straight chains, provide rigidity –
gives the CRUNCH to fruits and vegetables!
There are hydrogen bonds between the
polysaccharides, which make them very
Chitin (Structural role) – Straight Linear Chains
Structure in the exoskeleton of arthropods and
the cell walls of fungi.