This document provides information about chemical compounds found in cells. It defines elements as substances made of only one type of atom that cannot be broken down further. Compounds contain two or more elements and have properties different from their components. The four main types of organic compounds found in cells are carbohydrates, lipids, proteins, and nucleic acids. Carbohydrates and lipids store energy, while proteins perform important functions and nucleic acids carry genetic information that directs cell activities.

1. Chemical
Compounds
in Cells
CHAPTER 3.1

2. Elements
 An element is any substance that cannot be
broken down into simpler substances.
 The smallest unit of an element is an atom.
 An element is made up of only one type of atom.
 Example of an element is carbon.

3. Elements
Definition of an element:
An element is a pure substance which cannot be
split up into two or more simpler substances by
chemical means.

4. Elements
Note that an element:
 Consists of only one kind of atom,
 Cannot be broken down into a simpler type of matter by
either physical or chemical means
 Can exist as either atoms (e.g. argon) or molecules (e.g.,
nitrogen).

5. Examples of elements
Elements are made up of tiny particles
Elements can be further classified into two groups:
Is the smallest particle
of an element and has
the same chemical properties
of the element
Is made up of two or more
atoms that are chemically
bonded together
(note: these atoms are of the
SAME element!!)
Hi, I am from
the “Noble gas”
family and I
work alone
We are the
same!!

6. These are elements!
Atoms of same
element
Cu
copper
element
Na
sodium
element
He
helium
element
Molecules of same
element
H
Hydrogen gas
element
O
H
OO
ozone

7. Atoms
An element is made of tiny particles
called atoms.
The atoms of an element is different
from that of another element.

8. Elements-
Atoms
Microscopic view
of the atoms of
the element
argon (gas
phase).
Consists of
only one kind
of atom

9. What is an atom?
Examples of models of
atoms:
H Na Cl
Hydrogen
atom Sodium
atom
Chlorine
atom

10. Compounds
 A compound is two or more elements that are
chemically combined.
 The smallest unit of a compound is a molecule.
 An example of a compound is water.

11. Compounds
Note that a compound:
 can be broken down into a simpler type of matter (elements)
by chemical means (but not by physical means),
 has properties that are different from its component elements,
and
 always contains the same ratio of its component atoms.

12. What is a compound?
A compound is a substance which is made up of two or
more DIFFERENT elements chemically combined
together.
- Chemical reactions taking place.
Qn: Is this a compound?
It only contains
one type of
element.
Qn: Is this a compound?
It only contains
one type of
element.
H
O
H
O
O
Qn: Is this a
compound?
It is not chemically
combined.

13. So, what is a compound
then?
H
Water Ammonia gas
Consists of two or more different elements
And
They are chemically combined together!

14. Chemical Formula
H
Water Ammonia gas
Shows the elements in the compound and the ratio of the elements.
The Chemical Formula of water is H2O
The Chemical Formula of Ammonia Gas is NH3

15. Compounds
Microscopic view of
the molecules of the
compound water (gas
phase). Oxygen
atoms are red and
hydrogen atoms are
white.

16. ELEMENTS
COMPOUNDhydrogen
(colourless
gas)
oxygen
(colourless
gas)
lighted
splint
heat, light
and
explosion
water
(colourless liquid)
Making compounds from their
elements
Example: Making water (picture)
Water
moleculeOxygen
molecule
Hydrogen
molecule
mixture of
hydrogen
and
oxygen
water
Example: Making water
(models)
heat,
light
and
explos
ion

17. The Compound called
water

18. Water
 Water makes up about two-thirds of our bodies.
 Water plays many important roles
 Water dissolves chemicals that the cells need.

19. Water
 Most chemical reactions within the cells could not
take place without water.
 Water helps the cells keep their size and shape.

20. Water
 Water changes temperature slowly
 So, it helps keep the temperature of the cells from
changing rapidly.

22. Organic and Inorganic
Compounds
 Inorganic compounds do not contain carbon.
 Organic compounds contain carbon and
hydrogen and usually are associated with living
things.

26. Four groups of Organic
Compounds
 Carbohydrates
 Lipids
 Proteins
 Nucleic Acids

27. Carbohydrates
 Made of the elements carbon, hydrogen,
and oxygen
 Supply energy for cell processes, form
plant structures; short-term energy
storage
 Sugars and starches are carbohydrate.

34. Starch
 Why do plants convert sugar into starch?
 To store energy

35. Carbohydrates
 Important component of cell parts
 Cellulose found in cell walls are a type of
carbohydrate
 Carbohydrates are also found in cell membranes.

36. Lipids
Types of lipids:
 Fats
 Oils
 Waxes

37. Lipids
 Fats, Oils and Waxes

38. Lipids
 Made of the elements carbon, hydrogen,
and oxygen
 Store large amounts of energy long term
 Even more than carbohydrates
 Form boundaries around cells – cell
membranes are made mainly of lipids

40. Proteins
 Large, organic molecules
 Made of the elements carbon, oxygen,
hydrogen, nitrogen, and, in some cases,
sulfur

41. Proteins in food

42. Structure of proteins
 Protein molecules are made up of smaller molecules called
AMINO ACIDS
 Amino acid

44. From Amino acid to
Protein
 There are only 20 amino acids, but cells can
combine them in 10000s different ways.
 Kind of like how you can combine the 26 letters of
the alphabet in MANY different ways.

45. From Amino acid to
Protein
 Same way as one change in a word, can change
its meaning
 Eg. Rice vs race
 One change in the amino acid order or type
changes the protein.

46. Functions Proteins
 Proteins form part of the cell membranes.

47. Functions Proteins
 Proteins make up many of the organelles in the cell.
 Regulate cell processes and build cell structures

48. Functions Proteins
 Make up Enzymes, skin, and hair

49. Enzymes
 Enzymes are a type of protein
 Play an important role in the chemical reactions
that take place in cells.
 An enzyme is a type of protein that speeds up a
chemical reaction in a living thing.

50. Enzymes
 Without enzymes many chemical reactions that
are necessary for life would either take too long
or not occur at all.

51. Enzymes
 For example: Chew the cracker – DO NOT
SWALLOW.
 Keep chewing…. What do you notice?

52. Enzymes
 It becomes sweet!!
 That is because the enzymes in your saliva speeds
up the digestion of food by breaking down the
starches into sugars in your mouth

54. Nucleic Acids
 Very long organic molecules.
 Made of the elements carbon, oxygen,
hydrogen, nitrogen, and phosphorus
 Carry hereditary information
 Used to make proteins

55. Nucleic Acids
 Carry ALL the instructions that cells need
to carry out all the functions of life.
 Two kinds of nucleic acids:
 Deoxyribonucleic acid (DNA)
 Ribonucleic acid (RNA)

57. DNA
 The genetic material that carries all the
information about an organism
 Passed from parent to offspring
 Directs all the cell’s functions
 Most DNA is found in the chromatin in the
nucleus of the cell

59. RNA
 Plays an important part in the production
of proteins.
 Found in the cytoplasm and the nucleus