Cell cycle is the series of events that occur in a cell to - Spindle fibers

prepare cell division and to produce two new daughter connect to

cells. chromosomes
ANAPHASE /APART - Copies
Phases of cell cycle include two major activities: chromosome
divide
• Interphase - Spindle fibers
• M-phase (Mitotic phase) pull
chromosomes to
Interphase is the longest phase of the cell cycle process. opposite poles
It is also the known as the resting phase. Although the cell TELOPHASE /TWO - Chromosomes
is at rest but it is metabolically active. The metabolic uncoil
- Nuclear
activities of the cell can be observed through cell growth,
envelopes form
production of nutrients and enzymes and replication of - 2 new nuclei are
DNA. formed
- Spindle fibers
Interphase has 3 sub-stages: disappears
➢ G1 phase (Gap phase/Growth 1 phase) - the
cell grows physically larger, copies organelles, Cytokinesis, the cytoplasm of the cell is split in two,
and makes the molecular building blocks it will making two new cells. Cytokinesis usually begins just as
need in later steps. proteinsynthesis also occurs mitosis is ending, with a little overlap. Importantly,
enable the cell to increase the amount of cytosol. cytokinesis takes place differently in animal and plant
➢ S-phase (Synthesis phase) - is the longest and cells.
the most essential stage of interphase. It is due to
the complexity of the replication of genetic Cell Cycle Checkpoints - checkpoint is a stage in the
material which results to the duplication of DNA eukaryotic cell cycle at which the cell examines internal
and external cues and "decides" whether or not to move
prior to the cell division process. It also duplicates forward with division.
a microtubule-organizing structure called the
centrosome. The centrosomes help separate DNA ▪ G1 checkpoint is the main decision point for a
during M phase. cell - that is, the primary point at which it must
➢ G2 phase (Gap phase/Growth 2 phase) - is the choose whether or not to divide. Once the cell
final stage where the cell prepares itself for cell passes the G1 checkpoint and enters S phase, it
becomes irreversibly committed to division. That
division process, and also ensures that the DNA
is, barring unexpected problems, such as DNA
replication completes. damage or replication errors, a cell that passes
➢ M phase (mototic phase) - the cell divides its the G1 checkpoint will continue the rest of the way
copied DNA and cytoplasm to make two new cells. through the cell cycle and produce two daughter
M phase involves two distinct division-related cells.
processes: mitosis and cytokinesis. Checks for:
Cell Size Growth Factors
Mitosis, the nuclear DNA of the cell condenses into visible Nutrients DNA Damage
chromosomes and is pulled apart by the mitotic spindle, a
specialized structure made out of microtubules. Mitosis • G2 checkpoint make sure that cell division goes
smoothly (produces healthy daughter cells with
takes place in four stages: prophase (sometimes divided
complete, undamaged DNA), the cell has an
into early prophase and prometaphase), metaphase, additional checkpoint before M phase
anaphase, and telophase. Checks for:
DNA Damage
PROPHASE - Chromosomes DNA replication completeness
coil up
- Nuclear
• Spindle Checkpoint (M checkpoint) - the cell
envelope
examines whether all the sister chromatids are
disappears
correctly attached to the spindle microtubules.
- Spindle fbers
Checks for:
form
Chromosome attachment to spindle at
METAPHASE /MID - Chromosome
metaphase plate
line up in the
middle of cell