Transcript Cell Cycle Notes

Chapter 10: Cell Cycle Notes
Why Divide?
The cell theory states that:
All cells come from other living cells.
1. Cells divide for the survival of the
individual organism
2. Cells divide for the survival of the
species (group of similar organisms)
Cells divide for the survival of
the individual organism
Cell division is used for growth,
development, maintenance, and repair
of the organism. This is carried out by:
Mitosis- division of body cells to make
more of the same kind of cell.
– The parent cell is the original cell inside the
organism that will divide.
– The daughter cells are the two identical
cells created when the parent cell divides.
Cells divide for the survival of
the species 
To reproduce more organisms that look
similar to their parents:
Sexual reproduction -two separate
organisms produce egg and sperm that
must combine or fuse together to
produce offspring.
– Meiosis process of making egg cells and
sperm cells.
– Fertilization the fusion of egg and sperm
to produce a new organism.
Cells divide for the survival of
the species 
To reproduce more organisms that look
similar to their parents:
Asexual reproduction- offspring are
produced by only one individual
organism.
– Spores are produced by mold and other
fungi that grow all by themselves into more
fungi.
– Binary fission is the process of a bacterium
splitting in two new bacteria
Cell Cycle
Cell Cycle- is defined as the life of a cell
from the beginning of one interphase to
the beginning of the next interphase.
(with cell division in between)
– Step (1.) Interphase (G1,S & G2 phases)
– Step (2.) Cell Division
–Mitosis-division of nucleus
–Cytokinesis- division of cytoplasm
Cell Cycle: Interphase
Step 1: Interphase – is the growth and
development phase of the cell cycle.
Three parts:
(1.) Growth One or G1 phase
(2.) Synthesis or S phase (make DNA)
(3.) Growth Two or G2 phase
G1 phase
initial growth phase of the cell.
The cell grows and carries out its routine
functions.
This is the longest phase of interphase.
Many cells stop growing and get stuck in
this phase for the entire life of the organism
(Ex. Nerve cells).
Other cells get stuck in G1 of interphase
until cell division is needed for growth or
repair.
S phase (synthesis)
is when DNA replication occurs.
After DNA replication the cell has two
complete copies of its DNA.
At this point, the cell is committed to
dividing.
G2 phase
the cell continues to grow and the final
preparations for cell division are made.
G2
G1
S
Cell Cycle: Cell Division
Step 2: Cell Division: -the creation of two
daughter cells from one parent cell.
*Each daughter cell will have the same
number of chromosomes as the parent
cell.*
Two Parts of Cell division:
Mitosis and Cytokinesis
Cell Division: Mitosis
Mitosis – “division of the
nucleus”. It is a synchronized
set of events that will separate
chromosomes, so that the two
nuclei formed will be identical.
It is the beginning of cellular
division.
(PMAT)– Prophase, Metaphase,
Anaphase, & Telophase
•
Mitosis Animation Simple
Cell Division: Cytokinesis
Cytokinesis “division of the cell
cytoplasm”. It is the physical separation
of the cytoplasm into two new daughter
cells.
It is the end of cell division.
New cells pinch off from each other in
animal cells. In plants, a cell plate is
formed, because plants also have cell
walls to form.
Slide # 5
Vocabulary
1. Chromosome: coiled DNA
structures within the nucleus
containing genetic information
that is passed on from generation
to generation
2. Sister Chromatid: one of two
identical “sister” parts of a
duplicated chromosome-formed
during S phase
3. Centromere (A): chromosome
region that joins 2 sister
chromatids
Prophase: 1st Phase
1. DNA coils & becomes
chromosomes
2. Centrioles move to opposite
ends of cell
3. Spindle fibers attach to
chromosomes
4. Nuclear membrane breaks
down
Metaphase
1. Spindle fibers push & pull
chromosomes until they
line up across center of
cell
2. Centromere of each
chromosome pair is
attached to a spindle fiber
Anaphase
1. Spindle fibers shorten &
paired chromatids separate
2. Spindle fibers pull
separated chromosomes to
opposite ends of the cell
3. Centromere of each pair
divides; now have individual
chromosomes
Telophase
1. Chromosomes begin to
uncoil and decondense
2. Nuclear membrane
reforms around each
new set of chromosomes
Cytokinesis
Cytokinesis is division of
the cytoplasm
2. Distributes the organelles
a. In animal cells, the cell
membrane pinches in
two.
b. In plant cells, a cell
plate forms across the
middle.
1.
What Phase Of the Cell Cycle Is It?
A
Anaphase
D
Interphase
B
C
Telophase
Cytokinesis
E
F
Metaphase
Prophase
CANCER
is the caused by uncontrolled cellular
division.
Typically, most cells don’t divide unless it is
for repair or maintenance.
Cancerous cells keep dividing; crowding
out and stealing nutrients from healthy
tissue.
Cancer “kills” when a mass of cancer cells
called a tumor interferes with the functions
of major organs.
BRAIN TUMOR
PANCREATIC CANCER
BREAST TUMOR
ORAL CANCER
The picture on the left shows a healthy right lung, and a small discolored left
lung. This indicates the presence of tumors, as seen in the picture on the right.