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Biological Molecules: Chapter 4 Part- 1, Formation of maltose molecule: -…
Biological Molecules
:
Chapter 4
Part- 1
Basics:
Organic molecules
(mainly containing carbon, hydrogen and oxygen) make up an organism.
Organic molecules provide energy, and are raw materials for growth and repair of tissues.
Biological molecules are important because they
provide provide energy for different life processes and raw materials for growth and repair of tissues.
The 4 main groups of organic chemicals used by living things are:
carbohydrates, lipids/ fats, proteins and nucleic acids.
Carbohydrates:
Carbohydrates are
polysaccharides which are made up of many monosaccharides.
Monosaccharides are the
smallest units
: E.g.
Glucose
Polysaccharides
are chains of monosaccharides: E.g.
Starch, Glycogen and cellulose
Monosaccharides
are main
sources of energy
and
polysaccharides
are
good stores of energy
.
They contain
carbon, hydrogen and oxygen.
Other important notes:
All carbohydrates contain carbon, hydrogen and oxygen only. They are made up of sub units which are called monosaccharides. For example:- glucose and fructose. When 2 glucose molecules join together, they form
disaccharides
(
maltose
). When 2 molecule of glucose and 1 molecule of fructose joins together, they form a disaccharide
sucrose
.
When many monosaccharides join together, they form a polysaccharide. E.g.: starch, glycogen and cellulose. They are formed when hundreds of glucose molecules are joined together in long chains.
Monosaccharides and disaccharides: Soluble in water
Polysaccharides: Insoluble in water
Glycogen
is a
polysaccharide
that form
food storage substances
in many
animal cells
. It is also considered as an energy molecule and is stored in liver.
Starch
is an important
storage substance
in the
plastids of plant cells
. In cellulose,
chains of glucose molecules
are grouped together to form microscopic
fibers
. These fibers ae laid down to form the cell wall in plant cells.
Lipids:
Lipids are formed from
fatty acids and glycerol
.
They too are excellent
stores of energy
and form
barriers for cells
in it's surroundings.
Contains
carbon, hydrogen and oxygen
.
Lipids form part of cell
membrane
and internal membranes of the cell such as the nuclear membrane.
Liquid lipids
are known as
oils
.
Glycerol and fatty acids
are
jointed
together by
chemical bonds
.
Examples of fatty acids
: Stearic acids, oleic acids and palmitic acid.
Lipids are fats/ oils which are formed from carbon, hydrogen and oxygen only.
A molecule of fat is made up of
3 molecules of fatty acids combined with 1 molecule of glycerol
.
Important part of cell membranes, cell organelles and are also a good source of energy.
Formation of maltose molecule: