Download dividing

Just as humans go through a life cycle, cells go through a cell
cycle.
reproduce
marriage
grow
puberty
The cell cycle:
Chromosomes
Divide
Grow
DNA
Replication
Daughter
cells
Cell Cycle
G
R
Series of events cells go through as they grow,
replicate
their
C
D
D
DNA, form chromosomes,
and divide
into two daughter
cells.
D
It is considered a cycle because each daughter
cell starts the
D
process over after division
is complete.
Cell cycle diagram in SG:
Each section of the
diagram represents
a different event in
the cell’s life
Circular diagram =
cycle
GROWTH
DNA
LOOSENS
CYTOPLASM
DIVIDES
NUCLEUS
DIVIDES
CHROMOSOMES
FORM
DNA
REPLICATION
The cell cycle is divided into 2 main parts.
GROWTH
DNA
LOOSENS
CYTOPLASM
DIVIDES
NUCLEUS
DIVIDES
CHROMOSOMES
FORM
DNA
REPLICATION
D
This part of the cell cycle is all about division…
GROWTH
DNA
LOOSENS
CYTOPLASM
DIVIDES
NUCLEUS
DIVIDES
CHROMOSOMES
FORM
DNA
REPLICATION
P
…and this part of the cell cycle is all about preparing
for
division.
GROWTH
DNA
LOOSENS
CYTOPLASM
DIVIDES
NUCLEUS
DIVIDES
CHROMOSOMES
FORM
DNA
REPLICATION
M = MITOSIS
INTER = BETWEEN
GROWTH
DNA
LOOSENS
CYTOPLASM
DIVIDES
M
PHASE
NUCLEUS
DIVIDES
CHROMOSOMES
FORM
DNA
REPLICATION
Interphase
GROWTH
DNA
LOOSENS
CYTOPLASM
DIVIDES
M
PHASE
NUCLEUS
DIVIDES
DNA
REPLICATION
CHROMOSOMES
FORM
C cycle
C
P
D
Part of the cell
when the cell prepares
for division.
M Phase
NEW PAGE
IN NOTES
GROWTH
DNA
LOOSENS
CYTOPLASM
DIVIDES
M
PHASE
NUCLEUS
DIVIDES
DNA
REPLICATION
CHROMOSOMES
FORM
C cycle
C
D
N
Part of the cell
when the cell divides
(first the nucleus,
C
then the cytoplasm.)
L
Interphase is longer
than M phase.
GROWTH
DNA
LOOSENS
CYTOPLASM
DIVIDES
M
PHASE
NUCLEUS
DIVIDES
CHROMOSOMES
FORM
DNA
REPLICATION
R
This is because DNA replication
occurs during interphase.
Remember, the DNA molecule is extremely long, so it takes a
long time to replicate…
…and it must be replicated without making any mistakes.
How can you tell if a cell is in M phase or interphase?
Identifying Cells in the Cell Cycle
Interphase
(preparing)
Chromosomes
M phase
(dividing)
D
Since M phase cells are in the process of dividing,
they have
C
visible chromosomes.
GROWTH
DNA
LOOSENS
CYTOPLASM
DIVIDES
M
PHASE
NUCLEUS
DIVIDES
CHROMOSOMES
FORM
DNA
REPLICATION
M phase cells:
X
X
X
X
Identifying Cells in the Cell Cycle
Interphase
(preparing)
Fully-formed
Chromosomes
M phase
(dividing)
I
D
Since interphase
cells are not ready to divide,
they do not
C
contain chromosomes.
GROWTH
DNA
LOOSENS
CYTOPLASM
DIVIDES
M
PHASE
NUCLEUS
DIVIDES
CHROMOSOMES
FORM
DNA
REPLICATION
Interphase cells:
Identifying Cells in the Cell Cycle
No
chromosomes
Interphase
(preparing)
Fully-formed
chromosomes
M phase
(dividing)
You’ll notice that most of these cells are in interphase, since
L
interphase takes longer
than M phase.
Interphase is divided into 3 parts.
GROWTH
DNA
LOOSENS
G1
CYTOPLASM
DIVIDES
M
PHASE
NUCLEUS
DIVIDES
CHROMOSOMES
FORM
S
G2
DNA
REPLICATION
G
O
During G1, the cell grows
and makes new organelles.
GROWTH
DNA
LOOSENS
G1
CYTOPLASM
DIVIDES
M
PHASE
NUCLEUS
DIVIDES
CHROMOSOMES
FORM
S
G2
DNA
REPLICATION
R
E
During S phase, the DNA is replicated
by enzymes.
GROWTH
DNA
LOOSENS
G1
CYTOPLASM
DIVIDES
M
PHASE
NUCLEUS
DIVIDES
CHROMOSOMES
FORM
S
G2
DNA
REPLICATION
What happens during G2?
DNA MOLECULE
REPLICATED DNA
E
During G2, the cell checks for any errors
made during DNA
R
C
replication
and fixes them before chromosomes
form.
GROWTH
DNA
LOOSENS
G1
CYTOPLASM
DIVIDES
M
PHASE
NUCLEUS
DIVIDES
S
G2
CHROMOSOMES
FORM
CHECK FOR
ERRORS
DNA
REPLICATION
How can you tell if a cell is in G1, S, or G2 of interphase?
Identifying Cells in the Cell Cycle
No
chromosomes
S
Interphase
(preparing)
End of
G2
Fully-formed
chromosomes
M phase
(dividing)
G1
What would G1 cells look like?
GROWTH
DNA
LOOSENS
G1
CYTOPLASM
DIVIDES
M
PHASE
NUCLEUS
DIVIDES
S
G2
CHROMOSOMES
FORM
CHECK FOR
ERRORS
DNA
REPLICATION
Identifying Cells in the Cell Cycle
No
chromosomes
S
Interphase
(preparing)
End of
G2
Fully-formed
chromosomes
M phase
(dividing)
G1
Small (just divided)
G1 cells:
What would S phase cells look like?
GROWTH
DNA
LOOSENS
G1
CYTOPLASM
DIVIDES
M
PHASE
NUCLEUS
DIVIDES
S
G2
CHROMOSOMES
FORM
CHECK FOR
ERRORS
DNA
REPLICATION
Identifying Cells in the Cell Cycle
No
chromosomes
G1
S
Interphase
End of
G2
Fully-formed
chromosomes
M phase
Small (just divided)
Fully-grown
S phase cells:
What would cells at the end of G2 look like?
GROWTH
DNA
LOOSENS
G1
CYTOPLASM
DIVIDES
M
PHASE
NUCLEUS
DIVIDES
S
G2
CHROMOSOMES
FORM
CHECK FOR
ERRORS
DNA
REPLICATION
Identifying Cells in the Cell Cycle
No
chromosomes
G1
S
Interphase
End of
G2
Fully-formed
chromosomes
M phase
Small (just divided)
Fully-grown
DNA starting to
condense
End of G2 cells:
Which cells are in interphase? Why? No chromosomes
A
B
C
D
Which cell is in M phase? Why? Fully-formed chromosomes
A
B
C
D
Which cell is in S phase? Why? Fully-grown
A
B
C
D
Which cell is in at the end of G2? Why? DNA is starting to
condense
A
B
C
D
Which cell is in G1? Why? Small (just divided)
A
B
C
D