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?
In the drawings below, you can see the chromosomes in the nucleus going through the process of mitosis, or division. If you have a microscope (400X) and a properly stained slide of the onion root tip (or allium root tip), you can see the phases in different cells, frozen in time. You will be looking at strands of DNA inside the cell! First Phase is called Prophase, the DNA molecules of the chromosomes condense.