T2 Lesson 9 - Mitosis Flashcards
What is mitosis?
Part of cell division in which the nucleus divides eventually producing 2 daughter cells which are genetically identical to the parent cell.
We say the new cells are clones
Give some examples of the use of mitosis?
-cloning
-Asexual reproduction
-making new deploid cells
-growing and healing
What is asexual reproduction?
When an organism reproduces (makes more of itself) without exchanging genetic information with another organism through sex.
How do humans use mitosis?
- make new diploid cells for growing and healing.
The 4 stages of mitosis
-Prophase
-metaphase
-anaphase
-telophase
What is a deploid cell?
A cell that contains a complete set of chromosomes in its nucleus.
Each chromosome in a diploid cell has two copies, which are arranged in homologous pairs.
Delpoid cells contain……….
a full set of DNA
DNA is very long so it coils itself around a protein called……..
**histones **and wrapped into tight shapes called **chromosomes. **
How many chromosomes are in a full set of DNA?
46
23 (from father)
23 (from mother)
What is meant by **homologus ** pair?
The chromosome of a mother matched to the same chromosome from a father
What needs to happen before mitosis occurs?
The DNA inside a nucleus need to replicate (this is called Interphase)
How many chromosomes are in a deploid cell after replication?
92 - the amount of DNA doubles from 46
PROPHASE
After DNA replication there are now two copies of each chromosome.
- During prophase chromosomes thicken so they become visible under a microscope. Identical copies join together at their
centre with a structure called a centromere. - Each chromosome in the pair is now called a chromatid.
- The* nuclear membrane breaks down,* so the chromatids break free.
METAPHASE
- Spindle fibres form from the centrioles at either pole (end) of the cell.
- The chromosomes line up at the equator (centre) of the spindle and attach to it by their centromeres.
ANAPHASE
- Spindle fibres shorten pulling chromatids to opposite poles.
- This means separate, identical chromosomes get dragged to either end of the cell (called poles just like the ends of Earth) on the spindle structure.
TELOPHASE
- The cytoplasm starts to divide to produce two daughter cells.
- Each is an identical copy to the parent.
- Nuclei form around the chromosomes.
Looking at the image describe the different stages of mitosis?
CENTROMERE
Part of the chromosome where the 2 sister chromatids are held together and which is the attachment site of the spindle fibers during cell division
CHROMATID
One of two identical parts or arms of a chromosome
Can you name a type of cell that divides by mitosis?
Stem cell
When do stem cells stop dividing by mitosis?
When they are asked to turn into specialised cell. This is called differentiation.
Name the missing stage of mitosis.
Anaphase
Give the correct label to replace the question mark
centromere
Give the correct label to replace the question mark.
Spindle fibre
In what stage are these animal (left) and plant (right) cells?
Metaphase as the chromosomes have lined up along the cells equator.
Notice the plant cell is more rigid due to its strong cellulose cell wall.
At what mitosis stage is the cell in the centre of the image?
Telophase
At what stage is this cell in the process of mitosis?
Anaphase
The ant only has 1 chromosome in a diploid cell. The Atlas blue butterfly has 448-452 chromosomes in a diploid cell. How many chromosomes do you have in a diploid cell?
46
