The Cell Cycle
Science 9 Biology
What will we cover today?
01
02
03
04
Prophase
Metaphase
Anaphase
Telophase
05
Interphase
Mitosis
06
Cytokinesis
What is the Cell Cycle?
The cell cycle is the sequence of events in the cell from one cell division to another.
https://www.nelson.com/bcscienceprobe9/documents/bc9UnitApreview.pdf
Cycles and Circles in science
https://www.nelson.com/bcscienceprobe9/documents/bc9UnitApreview.pdf
https://www.nelson.com/bcscienceprobe9/documents/bc9UnitApreview.pdf
Interphase
Mitosis
Cytokinesis
Interphase
01
The day-to-day life of the cell
Interphase
Cells grow and carry out day-to-day functions
The cell spends about 90% of the cell cycle in interphase
A copy of each chromosome is made.
Sister Chromatids
The chromosome and its copy are known as Sister Chromatids.
https://www.nelson.com/bcscienceprobe9/documents/bc9UnitApreview.pdf
https://www.nelson.com/bcscienceprobe9/documents/bc9UnitApreview.pdf
https://www.nelson.com/bcscienceprobe9/documents/bc9UnitApreview.pdf
Mitosis
Prophase
02
The first stage of Mitosis
“Pro” = before
Prophase
In prophase the sister chromatids have grown thicker and we can now see them under a microscope.
https://www.thoughtco.com/stages-of-mitosis-373534
Prophase
The sister chromatids join at the center and make an ‘X’
The piece that joins the sister chromatids is called the Centromere.
https://www.nelson.com/bcscienceprobe9/documents/bc9UnitApreview.pdf
Prophase
The nuclear membrane is then broken down and the chromosomes spread out in the cytoplasm
https://www.khanacademy.org/science/ap-biology/cell-communication-and-cell-cycle/cell-cycle/a/phases-of-mitosis
Prophase
The centrioles which were replicated during interphase move to opposite sides of the cell. Spindle fibres begin to form. Spindle fibres are like ropes, they are used to move the chromatids later in Mitosis.
https://s3-us-west-2.amazonaws.com/courses-images/wp-content/uploads/sites/1087/2016/12/26203940/Prometaphase.jpg
Centriole
Spindle Fibres
Metaphase
03
The second stage of Mitosis
“M” = middle
Metaphase
The spindle fibers attach to the sister chromatids and line them up along the middle of the cell
https://www.shutterstock.com/search/metaphase
Anaphase
04
The third stage of Mitosis
“A” = away
Anaphase
The sister chromatids are pulled apart and moved toward the poles of the cell.
Telophase
05
The final stage of Mitosis
“T” = two
Telophase
The two chromosomes each get their own cell membrane
https://www.britannica.com/video/73107/Mitosis-stages-metaphase-prophase-telophase-anaphase
Telophase
The spindle fibres disappear
https://www.britannica.com/video/73107/Mitosis-stages-metaphase-prophase-telophase-anaphase
Telophase
The chromosomes become thin… In a sense, telophase is like prophase in reverse.
https://www.biologyexams4u.com/2012/09/somatic-cell-formation-by-mitosis.html
Telophase
Two nuclei result. The resulting nuclei are identical replicas of the original nucleus.
Check your understanding #1
Place the following in chronological order:
Cytokinesis
06
Cytokinesis is the last step in the cell cycle!
Cytokinesis
Check your understanding #2
A cell that has 20 chromosomes undergoes mitosis. How many daughter cells will be created? How many chromosomes will each cell have? Discuss with your seat partner.
https://www.nelson.com/bcscienceprobe9/documents/bc9UnitApreview.pdf
Interphase
Mitosis
Cytokinesis
Summary
Prophase
Metaphase
Anaphase
Telophase