The Chemistry of Life
Our first topic Macromolecules focuses on the
Chemistry of Life
You are made up of chemical
elements and their compounds or
The basic elements of life are listed
on the Periodic Table.
Topic 1: Macro molecules
To be able to understand Biology we must ensure that
we can read, pronounce, spell, write and interpret
the language used.
What does ‘macro’ mean?
What is the definition for the term ‘molecule’?
Macro = BIG OR LARGE
A MOLECULE is made up of two or more atoms
chemically combined in a fixed ratio to form the
smallest particle of a substance which can exist by
Molecules may be represented by chemical formulae
The formula represents what atoms
combine chemically to form the
smallest possible particle of water.
So one molecule of water contains
two hydrogen atoms and one oxygen
The language of Biology
Page 19 Biology The Essentials workbook
Check out the list of terms given in Q1.
Could you explain what ……..each term means?
……..some of them mean?
………. any of them mean?
In order to achieve successful learning outcomes you must
be able to understand the language used and so must learn
definitions as we go.
There are 4 major groups of these large complex organic
M6 Polymer Principles
Four classes of macromolecules:
Polymers are made up of smaller parts
Polymers are formed through
Polymers are broken apart through
a hydrolysis reaction.
General Information about Carbohydrates
Are important energy sources for most organisms
Often end in “-ose”
Made of C, H, and O
“Hydrate”-hydrogen and oxygen are present in the same
proportions as in water (2 H: 1 O)
Use the molecular model kits to construct a glucose
Simple or single sugars are
Two linked monosaccharides
Long chains of monosaccharides are
Monosaccharides -one sugar unit –
are the simplest carbohydrates
They have a backbone of 3-7 carbon atoms
There are many –OH and –H functional groups present
They are usually found in ring form in cells
They are characterized by sweet taste
They have several polar -OH groups, so they dissolve in water
This is the most common
It is one of the products of
In animals, glucose is synthesized in
the liver and kidneys
Glucose is needed for ATP synthesis
during cellular respiration
Fructose is found in fruits and
It is classified as the sweetest
of all the sugars.
Ribose and deoxyribose are the building blocks for nucleic
these are two sugar units bonded
formed in condensation reactions
Maltose (two glucose units) is
present in germinating
Sucrose (glucose + fructose) is a transport form of sugar
used by plants and harvested by humans for food.
Lactose (galactose and glucose) is
present in milk
Large molecular compound of hundreds (or
thousands) of simple sugar units,
monomers, (monosaccharide's) linked
together. These include;
Cellulose – major component that encloses
plant cell cells. Tough and fibrous. Unable
to be digested and broken down by most
organisms including humans.
Chitin – found in exoskeletons of organisms
such as spiders, insects and crustaceans.
Acts as support.
Starch and Glycogen
Both are storage molecules for energy in
Plants- convert sugars into starch enables
the plant to store excess as an energy
Animals- excess glucose is stored in liver and
muscles as glycogen.
A gram of fat stores twice as much energy as
a gram of polysaccharide.
Practical Testing for
1.Used as structural component for
2.Energy storage systems in organisms.
3.Protective components of cell walls
They are organic molecules composed of
fatty acid chains linked to a glycerol
backbone. These include the following;
Fats and Oils- solid fat reserves stored as
adipose tissue. Acts as a storage of energy
and insulation against cold. Oils are mainly
liquids and found in plants and act as
reserves of energy.
Steroids- Large lipids and have important
roles as functional molecules e.g.
Waxes- produced by plants and animals. Act
a protective layers.
Elements of life
Back to pg 19 Essentials Q1
What do you think the difference between a
lipid and a phospholipid would be?
Phospho lipids contain
The element phosphorus can be located on the
Without phosphorus in the DNA we would not
Life depends on the chemical elements which
form a wide variety of different chemical
Phospholipids- includes a phosphate group, so
when in water arrange themselves in rows forming
a double layer which in turn creates a boundary
between the cell and it external environment.