Transcript Biological Molecules - Princeton High School

Carbohydrates, Lipids, Proteins, and
Nucleic Acids
Is it made of
carbohydrates?

Organic compounds composed of carbon,
hydrogen, and oxygen in a 1:2:1 ratio.

A carbohydrate with 6 carbon atoms would
have…
______ hydrogen atoms and ______ oxygen atoms
 Source of ENERGY
 Structural components of cells

Monomer of carbohydrate (simple sugar)

Most have 6 carbon atoms

Most common:
1) Glucose (main source of energy)
2) Fructose (found in fruits)
3) Galactose (found in milk)


Glucose, fructose, and galactose have the
same chemical formula.
C6H12O6
Same formula but different structural forms.

Disaccharide: two monosaccharides bond to
form a double sugar.


Example: sucrose
Polysaccharide: complex molecule
composed of three or more monosaccharides.

Glycogen: animals store glucose in the form
of the large, complex molecule – glycogen

Starch: plants store glucose molecules in the
form of starch.

Cellulose: large polysaccharide made by
plants, which provide strength and rigidity to
plant cells.
White bread is a simple carbohydrate (little
nutritional value, digested more quickly,
converted to fat more quickly)
 Whole grain bread is a complex carbohydrate
(high in fiber, vitamins and minerals, provide
more energy, digested slowly)


Large organic molecules

Nonpolar – do NOT dissolve in water

Include phospholipids, triglycerides, waxes,
steroids

Higher ratio of carbon and hydrogen to
oxygen than carbohydrates…. More C-H bonds

Store more energy per gram than most other
organic compounds

Carboxyl End
-COOH

Hydrocarbon End
C-H
Polar
Nonpolar
Hydrophilic
Hydrophobic
Saturated: Each carbon atom is single-bonded to 4 other
atoms; straight chain; molecules are close together; solid
at room temperature
Unsaturated: Double bonds in the C chain; kinked chain;
molecules are farther apart; liquid at room temperature
 http://www.youtube.com/watch?v=ESPNqKU
luRs
 Let’s
list some more differences in the form
and function of fatty acids
Triglycerides (FATS)
3
fatty acids molecules joined to 1 glycerol
 Saturated
triglycerides are composed of
saturated fatty acids (butter, other dairy
products, fat from red meat)
 Unsaturated
triglycerides are composed of
unsaturated fatty acids (mostly found oils
and in plant seeds)
Phospholipids
 Glycerol
is connected to 2 fatty acid
molecules and a phosphate group.
 The
plasma membrane
of the animal and plant
cells are composed of a
phospholipid bilayer.
Waxes
 Composed of a long fatty acid chain and
a long alcohol chain.


Waterproof and provide protection.
Found on the surface of plants and in the
ear canals of many animals (including
humans).

NOT composed of fatty acids

Four fused carbon rings which are
attached to other functional groups

Cholesterol (found in the cell and plasma
membrane)

Hormones such as testosterone and
estrogen
Is it made of
Proteins?
 Organic
molecules compose of hydrogen,
carbon, oxygen and NITROGEN
 Monomers
= AMINO ACIDS
 Examples:





Hair
Horns
Skin
Muscles
ENZYMES (to learn more about later!)
 20
different AA
 Central
carbon, C, that is covalently bonded
to 4 other groups
1.
2.
3.
4.
 AA
Hydrogen = blue
Carboxyl (-COOH) = green
Amine (-NH2) = yellow
R group = red (varies in each AA and
determines the AA’s form and function
can also be illustrated as a ball
 Dipeptide:
two amino acids bond
 Polypeptides: long chains of amino acids
(made up of 1 or more dipeptide)
 Making proteins: what builds them?

Reaction: condensation or hydrolysis

Water is released or used
 Some
proteins are very large, some are small.
 Protein shape:


Influences its function (form and function)
Shape can be influenced by factors like
temperature and solvent) … for example, egg white
is clear when it is uncooked, and white when it is
cooked
 RNA
or protein molecules that act as
biological catalysts

Catalyst – speeds up the reaction by lowering the
activation energy
 Essential
for cellular function
 Each Enzyme bonds with a specific Substrate
for form the Active Site
 Speed



Enzyme bonds to substrate and the enzyme
shape changed slightly 
The chemical bonds in the substrate are
weakened 
Lowers the activation energy
 What


up reactions – how????
happens after the reaction?
Enzyme releases the products
Enzyme is unchanged…
 BUT
changes in temperature and pH can
change the enzyme (denature it) and it may
not function properly or at all

Large and complex biological molecules

Store and transfer important information in the
cell

Genetic Code

Two types – both are polymers
1. DNA - DeoxyriboNucleic Acid
 2. RNA - RiboNucleic Acid


DNA is transcribed into RNA, which is translated
into PROTEINS
 Each



nucleotide is made of:
a phosphate group,
a five carbon sugar, and
a ring-shaped nitrogen base
 Nitrogen





bases
A - Adenine
C – Cytosine
G – Guanine
T – Thymine
U - uracil