PPT ABOUT CELL CYCLES SS - Angelina.pptx

At the end of the lesson,
students
must have:
1. Illustrated the different
phases of cell cycle

These are the words that you will encounter:
Spindle fiber- are thin, thread-like structures made of
microtubules that form during cell division.
Centromere- specialized region of a chromosome where
the two identical sister chromatids are joined together. It
serves as a point of attachment for spindle fibers during
cell division.
Chromosomes-thread-like structures made of DNA and
proteins found in the nucleus of eukaryotic cells.
Nuclear Envelope- double membrane structure that
surrounds the nucleus of eukaryotic cells.

• A cell is the basic structural and functional unit of
an organism, it undergoes a series of events called
the cell cycle that results in the formation of new
cells called daughter cells along with the
duplication of DNA.
• The cell cycle is the series of events that occur in a
cell leading to its division and duplication.
• It consists of interphase (G1, S, and G2 phase)
where the cell grows and replicates its DNA,
followed by mitosis (M phase) where the cell
divides into two daughter cells.
What is the Cell Cycle?

• Interphase is the longest stage of the cell cycle,
accounting for about 90% of the total cycle time.
• Interphase is crucial because it allows the cell to
grow, replicate its DNA accurately, and prepare for
cell division.
• It ensures that each daughter cell receives a
complete and accurate copy of the genetic
material.
• Interphase allows the cell to carry out its normal
functions and maintain homeostasis before
undergoing division.
INTERPHASE

1st growth stage after cell division
It's a critical phase where the cell prepares for
DNA replication in the subsequent S phase
G1 phase also includes regulatory checkpoints
where the cell assesses its environment and
internal conditions to determine whether it
should proceed to the next phase of the cell
cycle
G1 phase sets the stage for the rest of the cell
cycle by ensuring that the cell is adequately
prepared for DNA synthesis and division.
Interphase – G1 Stage

Interphase - S Stage
Original DNA
Two identical
copies of DNA
Synthesis stage
DNA is copied or replicated

2nd Growth Stage
Occurs after DNA has been copied
All cell structures needed for
division are made (e.g. centrioles)
Both organelles & proteins are
synthesized
Interphase - G2 Stage

The mitotic process, also known as
mitosis, is a series of stages that
occur during cell division. It
ensures that each daughter cell
receives an identical set of
chromosomes.
Mitotic phase

In Prophase, the cells get ready for
division
 Chromosomes Get Ready
Chromosomes, which holds the cell’s
instructions , condense and become
visible
 Nuclear Envelope Breaks
The cell starts taking down the walls of its
nucleus ,allowing chromosomes to move
around more freely.
 Spindle Fibers Form
Special ropes call spindle fibers start to
form, helping to move the chromosomes
to move the chromosomes where they
need to go during division.
PROPHASE

In metaphase stage , the cell sets the stage
for division by lining up all the chromosomes
neatly.
 Chromosomes Line Up
It's like organizing books on a shelf.
Chromosomes, which are condensed and
visible, line up neatly along the middle of the
cell. This middle line is called the metaphase
plate.
 Spindle Fibers Attach
Think of spindle fibers as strings that help
move the chromosomes. They attach to each
chromosome at a point called the
centromere, ensuring that each
chromosome is ready to split evenly.
METAPHASE

Anaphase is the phase of movement and
separation, ensuring that each new cell
will have a complete set of instructions to
function properly.
 Chromosomes Split Apart
Imagine each chromosome, which holds
the cell's instructions, splitting into two.
It's like pulling apart a pair of socks.
 Move to Opposite Ends
The separated chromosomes start
moving to opposite ends of the cell, like
two teams heading to different sides of a
field.
ANAPHASE

Telophase is the phase where things start to calm
down and get back to normal as the cell prepares
to split into two new daughter cells.
 Chromosomes Unwind
Imagine the chromosomes, which hold the cell's
instructions, starting to unwind and stretch out.
It's like letting go of tightly coiled springs.
 Nuclear Envelopes Reform
The cell starts to rebuild the walls of its nucleus
around each set of chromosomes. It's like putting
the walls back up after a party.
 Spindle Fibers Disappear
Those spindle fibers, which helped move the
chromosomes around, start to disappear. It's like
the ropes being put away after they've served
their purpose.
TELOPHASE

Cytokinesis is the final stage of the
cell cycle where the cytoplasm of a
parent cell is divided into two
daughter cells . It occurs after the
nuclear division and completes the
process of cell division. During
cytokinesis, the cell membrane
pinches inward ( in animal cells ) or
a cell plate forms ( in plant cells) ,
ultimately separating the cytoplasm
and organelles into two distinct
daughter cells.
Cytokinesis

PPT ABOUT CELL CYCLES SS - Angelina.pptx

PPT ABOUT CELL CYCLES SS - Angelina.pptx