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?
The meristematic region of the Allium (onion) is a region of active mitosis. The section is thin (one cell thick); cells are relatively large, the chromosomes take on stain nicely, are easily seen, and are few in number (around 16). In one root tip you may see examples of all five major phases of mitosis.he meristematic region of the Allium (onion) is a region of active mitosis. The section is thin (one cell thick); cells are relatively large, the chromosomes take on stain nicely, are easily seen, and are few in number (around 16). In one root tip you may see examples of all five major phases of mitosis.