cell division and extract DNA from vegetables
I often hear about DNA these days. Simply put, it's a basic blueprint for an organism in the nucleus of a cell. Here, we will observe cell division and conduct experiments to extract DNA.
Experiment 1: After all cell division is garlic
you need : Garlic, Styrofoam, pin, microscopic observation instrument, stain solution
First of all, divide the garlic into bunches and peel. Roots with a peeling stimulus. Fix some to Styrofoam with a pin. Fill the container with water. Blocks light. With garlic, you can prepare a lot in a small space. I haven't seen it recently, but cheap garlic from China is enough.
In summer, it takes a few days to root. You can get about 10 bottles from a bunch. Cut the tip about 5 mm and soak in 5% hydrochloric acid at 60 ° C for a few minutes. Take it on a glass slide and leave the tip 1 mm.
Crush with a glass slide. After staining with carmine acetate etc., it is examined under a microscope. If you give about 10 bottles to one group, there will always be good ones.
Find something that shows the state of cell division. At first, observe at 100x and look for small cells. Enlarge and observe where the chromosomes are visible
Anyway, the advantage of garlic is that it can be prepared in large quantities. Onions are often unsuccessful because they cannot be prepared very often. Instead of garlic, you can use long onion seeds rooted on a black cloth and stretched to about 1 cm. However, it is enough to give the garlic to the group one by one, so it is easy to use. I haven't seen Chinese garlic recently. Probably because of the flooding caused by the long rain last year.
Experiment 2: Extract DNA from onions
Grate 1/4 of the onion, add 3g of salt and a few drops of detergent, and stir well. Strain it with a tea strainer and gently add an equal amount of chilled ethanol. DNA emerges. Suck up with a dropper.
Put the sucked DNA on the filter paper. Stain with carmine acetate. After a few minutes, remove the color with hot water.
The part where the DNA is dripping is stained. This is the reason why not only DNA extraction but also staining was performed, but many children do not leave an impression when they see the extracted DNA because it ends with "Hmm". Therefore, I decided to do this experiment because I wanted to impress that it was named because the chromosomes (DNA) are stained in this way.
Experiment 3: Extract DNA from juice
You may want to let the students do onion and broccoli experiments and do the teacher's demonstration experiments. Take about 40 ml of orange juice (100% fruit juice). Gently pour the same amount of ethanol into it and the DNA will emerge. The white floating object in the left photo is DNA. In orange juice, the cells are destroyed and the DNA is already out of the nucleus. You can extract the DNA just by adding ethanol, but it may be too easy to feel like you are experimenting. However, it serves the purpose of showing the DNA to the students.
