After the third dose -- given at age 6 months -- your child will be 80% to 85% immune to whooping cough for 3 to 5 years. Everyone -- including adults -- from age 11 up should receive a booster vaccine, called Tdap. It's a combined tetanus, diphtheria, and pertussis booster vaccine.
How many chromosomes are in the nucleus of an onion root cell? There are 8 chromosomes in the nucleus of an onion root cell. The cells are undergoing mitosis, during which the amount of DNA is doubled even as the number of chromosomes â¦ remains constant. How many chromosomes do onions have?
plastids. Since onion bulbs are below ground they do not get the light necessary for chloroplast development. There are lots of web sites available that have information on this subject. Try a google search using the words chloroplasts and onions or onion chloroplasts. If you are interested in learning more about cells, onions are a good experimental organism. Onion root tips are great to study mitosis and meiosis and the thin membranous epidermis between the onion rings are perfect for observing plasmolysis.