Mitosis Flashcards
What percentage of the dust in your home is made up of skin cells?
70%
When do your skin cells replace themselves?
Every 20 days
when do liver cells replace?
Every 200 days
When do brain cells replace?
Every 30-50 days
When do red blood cells replace?
Every 120 days
When do stomach lining cells replace?
every 2 days
When do intestinal lining cells replace?
Every 3 days
What are the three stages of the cell cycle?
Interphase, mitosis and cytokinesis
What is interphase?
- The stage where the cell carry out the functions necessary for survival and cells that divide prepare for reproduction
- The longest stage in the cell cycle
What is mitosis?
- The stage where mitosis divides the duplicated contents of the cell’s nucleus into two equal parts
- The shortest stage in the cell cycle
What is cytokinesis?
The stage where cytokinesis separates the two nuclei and cell contents into two daughter cells
What happens in the first stage of interphase?
Growth and preparation: the cell increases to its full size and makes the proteins and molecules necessary for the cell to function. Some organelles begin to duplicate.
What happens in the second stage of interphase?
Replication: When DNA makes a copy of itself by separating the two sides of the DNA with an enzyme. The new bases pair with the original two sides.
What is the third stage of interphase?
Continued growth and preparation: The cell continues to grow and make proteins for the new cell made in cytokinesis (the daughter cell). Also, organelles are duplicated.
What are the sister chromatids and centromere?
the sister chromatids are the two sides of the chromosome joined together by the centromere.
What happens in the first stage of mitosis?
Early prophase:
- Replicated chromosomes coil into x-shaped chromosomes
- The nucleolus disappears and the nuclear membrane starts to break down
- Centrioles move to the opposite poles and spindle fibres attach to them
What happens in the second stage of mitosis?
Late prophase:
- spindle fibres finish forming and attach to the centrioles
- nuclear membrane completely disappears.
What happens in the third stage of mitosis?
Metaphase:
- The spindle fibres pull the chromosomes into a line in the middle of the equator
What is the fourth stage of mitosis?
Anaphase:
- the spindle fibres shorten, which pulls the centromeres apart and sister chromatids move to opposite sides of the cell (the sister chromatids are now considered a chromosome)
What is the fifth stage of mitosis?
Telophase:
- Spindle fibres disappear and the nuclear membrane forms around each set of chromosomes
- the nucleolus appears in both sets of chromosomes
- the cell is now ready to divide
What is cytokinesis?
The final stage of the cell cycle which separates the two nuclei into two daughter cells.
How does cytokinesis work in animal cells?
The cell membrane pinches together and separates the cytoplasm and organelles
How does cytokinesis work in plant cells?
A cell plate forms in between the cells and separates them
What are the three reasons why cells will not divide?
- There are not enough nutrients to support cell growth
- DNA within the nucleus has not been replicated
- DNA is damaged
What is cancer?
a disease that causes cell division to be uncontrollable. Cells grow in multiple layers which form tumours.
