2. In the time that it
In the time that it
takes you to read
takes you to read
this sentence, your
this sentence, your
body will have
body will have
made millions of
made millions of
new cells! Making
new cells! Making
new cells allows
new cells allows
you to grow and
you to grow and
replace cells that
replace cells that
have died.
have died.
3. The Life of a Cell
The Life of a Cell
Cell cycle: the life cycle
Cell cycle: the life cycle
of a cell
of a cell
Cell cycle begins when the
Cell cycle begins when the
cell is
cell is formed
formed and ends
and ends
when the cell divides and
when the cell divides and
forms new cells
forms new cells
Before a cell divides, it
Before a cell divides, it
must make a copy of its
must make a copy of its
DNA
DNA
4. DNA is organized into structures
DNA is organized into structures
called
called CHROMOSOMES
CHROMOSOMES
Copying chromosomes ensures that
Copying chromosomes ensures that
each new cell will be an exact
each new cell will be an exact copy
copy
of its parent cell
of its parent cell
5. How does a cell make more cells?
How does a cell make more cells?
Depends on whether it’s
Depends on whether it’s
prokaryotic (no nucleus)
prokaryotic (no nucleus)
or
or
eukaryotic (with nucleus)
eukaryotic (with nucleus)
6. Making More Prokaryotic Cells
Making More Prokaryotic Cells
Prokaryotic cells are
Prokaryotic cells are less
less
complex
complex than eukaryotic
than eukaryotic
cells
cells
Cell division is called
Cell division is called
“
“binary fission
binary fission”, which
”, which
means “splitting into two
means “splitting into two
parts”
parts”
Binary fission results in two
Binary fission results in two
cells that each contain one
cells that each contain one
copy
copy of the circle of DNA
of the circle of DNA
7. Eukaryotic Cells and Their DNA
Eukaryotic Cells and Their DNA
Eukaryotic cells
Eukaryotic cells
are more complex
are more complex
The chromosomes
The chromosomes
of eukaryotic cells
of eukaryotic cells
contain more
contain more DNA
DNA
than prokaryotic
than prokaryotic
cells
cells
8. Different kinds of
Different kinds of
eukaryotes have
eukaryotes have
different numbers
different numbers
of
of chromosomes
chromosomes
Example: humans
Example: humans
have 46
have 46
chromosomes
chromosomes
9. Think “more chromosomes = better
Think “more chromosomes = better
organism”?
organism”?
Not true! Humans have 46, but a lot of organisms have
Not true! Humans have 46, but a lot of organisms have
more than us!
more than us!
Butterfly = 380
Butterfly = 380
Goldfish = 94
Goldfish = 94
Horse = 64
Horse = 64
Amoeba = 40
Amoeba = 40
Tobacco plant = 48
Tobacco plant = 48
10. Homologous chromosomes:
Homologous chromosomes:
chromosomes that have the
chromosomes that have the same
same
sequence of genes and the same
sequence of genes and the same
structure
structure
11. Making More Eukaryotic Cells
Making More Eukaryotic Cells
The eukaryotic cell cycle includes
The eukaryotic cell cycle includes 3
3 stages:
stages:
1.
1. Interphase
Interphase: cell grows and copies its
: cell grows and copies its
organelles and chromosomes
organelles and chromosomes
2.
2. Mitosis:
Mitosis: complicated process of
complicated process of
chromosome separation
chromosome separation
3.
3. Cytokinesis
Cytokinesis: cell splits into two cells; these
: cell splits into two cells; these
cells are identical to each other
cells are identical to each other
13. 1
1st
st
: INTERPHASE
: INTERPHASE
Not actually part of
Not actually part of
mitosis
mitosis
Chromosomes are
Chromosomes are
copied
copied (# doubles)
(# doubles)
-Each chromosome
-Each chromosome
and its copy (sister
and its copy (sister
chromosome) change
chromosome) change
to sister chromatids at
to sister chromatids at
the end of this phase
the end of this phase
centromere
14. 2
2nd
nd
: PROPHASE
: PROPHASE
Mitosis
Mitosis begins (cell
begins (cell
begins to divide)
begins to divide)
Centrioles (or poles)
Centrioles (or poles)
begin to move to
begin to move to
opposite sides of cell
opposite sides of cell
Spindle fibers
Spindle fibers form
form
between the poles
between the poles
15. 3
3rd
rd
: METAPHASE
: METAPHASE
Chromosomes line
Chromosomes line
up down
up down the
the
middle
middle of the cell
of the cell
Homologous
Homologous
chromosomes pair
chromosomes pair
up and attach to
up and attach to
the spindle fibers
the spindle fibers
16. 4
4th
th
: ANAPHASE
: ANAPHASE
Chromatids (or
Chromatids (or
pairs of
pairs of
chromosomes)
chromosomes)
separate
separate and move
and move
to
to opposite
opposite ends of
ends of
the cell
the cell
17. 5
5th
th
:
: TELOPHASE
TELOPHASE
Two new
Two new nuclei
nuclei form
form
Chromosomes
Chromosomes
appear as chromatin
appear as chromatin
(
(threads
threads rather
rather
than rods)
than rods)
Mitosis
Mitosis ends
ends
18. 6
6th
th
: CYTOKINESIS
: CYTOKINESIS
Cell membrane moves
Cell membrane moves
inward to create two
inward to create two
daughter
daughter cells – each
cells – each
with its own
with its own nucleus
nucleus
with identical
with identical
chromosomes
chromosomes
19. Ways to Remember the Order of
Ways to Remember the Order of
Mitosis!
Mitosis!
I
I P
Proposed
roposed M
Marriage
arriage A
After
fter T
Tuesday’s
uesday’s C
Class.
lass.
I
I P
Picked
icked M
Melons
elons A
At
t T
The
he C
Circus.
ircus.
Can you think of
Can you think of
any?
any?
