Learning Intentions
• I can state that the nucleus controls all the cells activities.
• I can state that cell division results in the increase in the number of
cells in an organism.
• I can state that when a cell divides two new identical daughter cells
are produced.
• I know what the human chromosome complement is
• I can state why the chromosome complement in daughter cells must
be maintained I can describe the stages in cell division.
• I can state that cell division is essential to allow organisms to grow
and repair damaged parts, e.g. cuts, bones and broken bones.
Success Criteria
• Observe mitosis in plant cells
• I can put the stages of mitosis into the correct order
• I can confidently annotate and explain the stages of mitosis
• I can explain the use of mitosis for growth or repair in a body part.
• I can explain the need for the continuity of chromosome numbers.
From this…
To this
To this!!!
One chromosome
After
chromosome
replicates:
one
chromosome
consisting of
two chromatids
Make your own
chromosomes
Why do we produce new cells?
•
To repair damaged tissue
– Eg wounded skin
•
To grow
– Eg bones, muscles etc
•
To replace worn out tissue
– Eg blood cells, skin etc.
Mitosis is the name for the way that a
cell duplicates itself so that each
daughter cell receives an identical copy
of its genetic material.
At the end of mitosis, there will be two
cells instead of one. They will be
identical to each other.
Mitosis in Onion Root Tips
Daughter Cells of Mitosis
 It is important that the chromosome
complement of the daughter cells is the same
as that of the parent cell. This is because
the chromosomes contain the genetic
information which controls the development
and activities of the cell. Any change or loss
of chromosomes would mean that the cell
would not function properly.
 Identical to each other, but smaller than
parent cell
How many chromosomes
are in a human cell?
46 Chromosomes
Daugther cell
46 Chromosomes
Mother cell
46 Chromosomes
Daughter cell
How many chromosomes
will be in the human
Therefore chromosomes
daughter cells?
must make an identical copy
during cell division/mitosis
Mitosis Animation
How many chromosomes will each daughter cell have?
Chromosomes make exact copies of themselves
Chromosomes are long and thin, uncoiled and not
easily visible
Chromosomes shorten and thicken and are visible under a
microscope
Chromosomes consist of two chromatids joined by a
centromere.
The number of chromosomes in a body cell is called the
diploid number
Nuclear membrane disappears
Spindle fibres form
Chromosomes begin to line up at the equator
Chromatids pulled apart by spindle fibres
to opposite poles
Nuclear membrane reforms around chromosomes
Cytoplasm divides and division is complete
1 Which cell structure controls all the cell activities
including cell division?
Nucleus
24
24
18
2 What is the chromosome
complement of the following:
24
66
3 Why is it important that the chromosome
complement of daughter cells in a multicellular
organism is maintained?
So that every cell has the necessary genetic
instructions/genes
4 What process maintains this continuity?
Mitosis
This controls cell activities including cell division
The process by which a cell makes an exact copy
of itself
The number of chromosomes in a typical cell of an
organism (eg in humans it is 46)
During mitosis chromosomes make an exact copy
to form two of these
Where chromatids are joined together
During mitosis, this pulls the chromatids apart from
the equator of the cell
Mitosis increases the number of these in an
organism
Cells which are identical to original parent cell
(same chromosome complement)
Nucleus
This controls cell activities including cell division
Mitosis
The process by which a cell makes an exact copy
of itself
Chromosome The number of chromosomes in a typical cell of an
complement organism (eg in humans it is 46)
Chromatids
During mitosis chromosomes make an exact copy
to form two of these
Centromere
Where chromatids are joined together
Spindle fibre
During mitosis, this pulls the chromatids apart from
the equator of the cell
Cells
Mitosis increases the number of these in an
organism
Daughter
cells
Cells which are identical to original parent cell
(same chromosome complement)