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.
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
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.
21.
22. Organic and Inorganic
Compounds
Inorganic compounds do not contain carbon.
Organic compounds contain carbon and
hydrogen and usually are associated with living
things.
23.
24.
25.
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.
28.
29.
30.
31.
32.
33.
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.
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
39.
40. Proteins
Large, organic molecules
Made of the elements carbon, oxygen,
hydrogen, nitrogen, and, in some cases,
sulfur
42. Structure of proteins
Protein molecules are made up of smaller molecules called
AMINO ACIDS
Amino acid
43.
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.
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
53.
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)
56.
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
58.
59. RNA
Plays an important part in the production
of proteins.
Found in the cytoplasm and the nucleus