A whole onion root tip has a total of 100 cells. Of these 100 cells, 58 are in interphase, 17 are in prophase, 11 are in metaphase, 5 are in anaphase, and 9 are in telophase.
How many cells are in prophase?
Prophase is the first phase of mitosis, the process that separates the duplicated genetic material carried in the nucleus of a parent cell into two identical daughter cells. During prophase, the complex of DNA and proteins contained in the nucleus, known as chromatin, condenses.
What happens in prophase onion root tip?
Prophase: During this stage, the chromosomes super coil, condense and become visible for first time during the cell cycle. The spindle fibers start forming. The nuclear membrane starts disintegrating. Metaphase: During this stage, the spindle fibers reach and attach to centromere of each sister chromatids.
How do you count cells in an onion root tip?
- Turn on the microscope and put an onion root sample slide under the lense.
- Adjust the lense until image is in focus.
- Count the total number of cells in the view and record the number.
- Count the number of cells in interphase and record the number.
How many chromosomes do onion root tip cells have?
The root tip cells of onion were used to test the potentially genotoxic effects of Alprazolam. The test was carried out according to Fiskesjö protocol (4, 11-12) with some modifications. Common onion (Allium cepa L.) has eight pairs of relatively large chromosomes (2n = 16) that allows for the easy detection of CAs.
How many cells in the onion root tip lab were in interphase?
Sample answer: From examination of two images taken under a microscope, approximately 450 cells were tallied. Approximately 60% of the cells were in interphase. The next most common stage observed was prophase, and 35% of cells were in this phase.
How long does the cell cycle take in an onion root tip?
The cell cycle for onion root tips takes about 720 minutes (12 hours).
Which stage of mitosis in the cells at the tip of the onion root?
When telophase is complete and the new cell membrane (or wall in the case of the onion root tips) is being formed, the nuclei have almost matured to the pre-mitotic state.
Why are cells in an onion root tip undergoing mitosis?
Why is onion root tip used to demonstrate mitosis in this experiment? It is because of the meristematic cells that are situated in the tip of the roots that render the most desirable and suitable raw material to study the different stages of mitosis.
What is the function of an onion epidermal cell?
The epidermal cells of onions provide a protective layer against viruses and fungi that may harm the sensitive tissues. Because of their simple structure and transparency they are often used to introduce students to plant anatomy or to demonstrate plasmolysis.