lesson on the chemical components of the cells

1. The Chemicals of Living Cells

2. The chemicals of life
All living organisms are made up of chemical substances
Reactions between these substances keep the cytoplasm
(and the organism) alive. They are living processes.
The chemical substances described in the next series
of slides are carbohydrates, proteins and lipids, but there
are hundreds of others.
2

3. Carbohydrates
Carbohydrates contain the elements carbon, hydrogen
and oxygen
Familiar carbohydrates are sugar and starch
Glucose, fructose, maltose and sucrose are sugars
Glucose and fructose have the same formula, C6H12O6
Sucrose and maltose have the same formula, C12H22O11
Carbohydrates provide the main source of energy for
respiration in living organisms
3

4. Glucose C6H12O6
C
C
C
C
C
C
HO
HO H
HO H
H OH
H OH
H2OH
A glucose molecule as a
straight chain
5 of the carbon
atoms may
be arranged in a ring
This molecule is
often represented
simply as a
hexagon
C O
C C
C C
C
4
SIMPLE SUGAR
A) Monosaccharides

5. 2 molecules of glucose can
join together to form a
molecule of maltose
maltose
sucrose is formed when
a molecule of glucose and
a molecule of fructose combine
Starch and cellulose are
formed from hundreds of
glucose molecules joined
to form a long chain
part of a starch
molecule
5
Polysaccharides
NOT soluble in WATER 
food storage
Complex sugars
B) Disaccharides (2 carbon rings)

6. Proteins
Proteins are made up of carbon, hydrogen and oxygen
molecules but with the addition of nitrogen
Carbohydrates are made up of glucose units.
Proteins are made up of units called amino acids
There are about 20 different amino acids. Examples are
glycine (Gly), alanine (Ala), valine (Val) and cysteine (Cyst)
joined together would make a small protein
Proteins can 1) make up the structure of cells
(STRUCTURAL): cytoplasm, nucleus, cell membranes
2) be Enzymes
6

7. Lipids
Lipids are fats and oils
* CHO
Present in * cell membrane and internal membranes
* droplets of fat stored in CYTOPLASM
They are made up from 3 molecules of fatty acids
+1 molecule of glycerol
8

8. CARBOHYDRATES PROTEINS LIPIDS
Elements they
contain
C,H,O C,H,O,N,S C,H,O
Smaller molecules of
which they are made
Glucose/simple sugar Amino acids (3) fatty acids and (1)
glycerol
Solubility in H2O Monosaccharides YES
Polysaccharides NO
YES NO
Food that contains
them
Bread, cereals, deserts,
potatoes, rice, pasta, jam,
sweets, lettuce
Meat, fish, chicken, egg
white, milk, cheese, pork,
peas, beans and cereals
Butter, oils, fat meat, junk
food, egg yolk

9. Why animals
need them
Easily available energy
(16kj/g)
Making
CELLS,ANTIBODIES,
ENZYMES; used for
ENERGY if all the stores
have run out (17kj/g)
*Source of ENERGY
(37kj)
*LONG TERM storage
of E in fat depots
*insulation (adipose
tissue)
*part of cell
membrane and
membrane systems
Things to
remember
ProteinsAminoacids
bloodstream build
up different proteins
(cytoplasm/enzymes)
aminoacids not
usedLiVERremoval
of amino group (-NH2)
 Glycogen Stored
or OXIDIZED for E
SUGAR
GLUCOSE

10. Salts and water
Water makes up the bulk of cytoplasm (75-90%)
All the chemical reactions in cytoplasm take place in
solution, i.e. in water
Water itself takes part in many of these chemical reactions
Salts of sodium, potassium and calcium and many others
play an important part in these reactions as IONS, they
take part in chemical reactions/ involved in determining
how much water enters or leaves the cell (OSMOSIS)
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11. VITAMINS
*take part in chemical reactions in the cell
*plants produce them/ animals have to obtain them
ready- made

12. Synthesis and conversion in
cells
Cells are able to build up or break down
CARBOHY DRATES, LIPIDS, PROTEINS
Animal cells CAN change * CARBOHYDRATES to
LIPIDS or viceversa
* PROTEINS to
CARBOHYDRATES
CAN’T make PROTEINS unless they receive
AMINOACIDS (plants can make their own starting from
sugar and salts)