mitosis
the process by which a cell produces two new identical nuclei
cell division
the dividing of a cell following mitosis
asexual reproduction
reproduction by one parent
sexual reproduction
reproduction by two parents
sex cell
a type of cell produced only by an organism that reproduces sexually
meiosis
the process by which sex cells form
fertilization
the joining of an egg cell and a sperm cell during sexual reproduction
zygote
the first cell of an offspring, formed when an egg cell and a sperm cell join
trait
a characteristic of an organism
DNA
the molecule in each cell that directs the cell's activities
gene
a section of DNA on a chromosome that controls a trait
base
one kind of molecule that makes up a DNA strand
heredity
the process by which traits are passed from parents to offspring
inherit
to receive from one's mother or father
dominant gene
a gene that prevents the expression of another gene
recessive gene
a gene whose expression is prevented by a dominant gene
purebred
an organism with two dominant or two recessive genes for a trait
hybrid
an organism with one dominant and one recessive gene for a trait
mutation
a permanent change in DNA that occurs when DNA copies itself