1. THE CELL CYCLE

2. The Cell Cycle The life cycle of the cell is called the cell cycle.
The life cycle begins
when the cell is
formed.
It ends when the cell divides

3. This is a form of asexual reproduction.
Mitosis is the process in which the nucleus divides to form two new nuclei.
This is a form of asexual reproduction.

4. Three reasons why cells reproduce by asexual reproduction: 1. Growth 2
Three reasons why cells reproduce by asexual reproduction: Growth Repair Replacement

5. Phases of Cell Division
Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
mitosis

6. Before a cell divides:
The cell must make a copy of its DNA.
DNA – deoxyribonucleic acid
DNA is the hereditary
material that directs
all cell activities, including the
making of a new cell.

7. Interphase This phase of the cell cycle is called interphase.
During this phase, the cell grows and
Copies its organelles and chromosomes.

8. The DNA of a cell is organized into structures
called chromosomes.
Chromosomes appear as threadlike coils (chromatin) at the start.
After each chromosome is
duplicated, the two copies
are called chromatids

9. Chromotids are
Held together in
the centromere.
The joined
chromotids
condense into
an “x” shape.

10. Copying chromosomes
ensures that each new
cell will be an exact copy
of its parents

11. Ninety percent or more of the cell cycle is spent in interphase.
During interphase, cellular organelles double in number,
the DNA replicates, and protein synthesis occurs.
(These are cells from a whitefish.)

14. prophase – chromosomes condense
from long strands into rod like structures.
(this is the longest phase)

16. metaphase:
paired chromatids
join at cell equator.
The nuclear
membrane
has been
dissolved.

20. a nuclear
membrane forms around
each set of chromosomes.

23. In cells that do not have cell walls,
division of the cytoplasm begins at the
cell membrane.
The cell membrane
pinches all the way
through the cell.
Two daughters
cell form.

24. The division of
cytoplasm is
called cytokinesis.

30. Average Cell Division Times
The amount of time it takes for one cell to completely divide in most mammals, including the human body, is about 24 hours.
Some cells take more or less time, depending on their purpose; a fly embryo takes only eight minutes to divide.
a human liver cell could take more than a year.
Gametes, cells used in sexual reproduction, can take decades to divide. Abnormal cell division can also occur, resulting in cancerous cells that multiply much more rapidly.

31. In the case of bacteria and rapidly growing organisms like a fetus or a young animal, cell division takes place very rapidly so the organism can grow and thrive.
Most of the cells in fully-grown organisms divide on a much slower scale to slowly renew the body.
The exception to this is in areas like the skin and bone marrow, which are constantly generating new cells so that, if an injury is sustained, the cells can divide quickly to heal the area.