MeiosisMeiosis (maɪˈoʊsɪs; , since it is a reductional division) is a special type of cell division of germ cells in sexually-reproducing organisms that produces the gametes, such as sperm or egg cells. It involves two rounds of division that ultimately result in four cells with only one copy of each chromosome (haploid). Additionally, prior to the division, genetic material from the paternal and maternal copies of each chromosome is crossed over, creating new combinations of code on each chromosome.
Y chromosomeThe Y chromosome is one of two sex chromosomes in therian mammals and other organisms. The other sex chromosome is the X chromosome. Y is normally the sex-determining chromosome in many species, since it is the presence or absence of Y that determines the male or female sex of offspring produced in sexual reproduction. In mammals, the Y chromosome contains the gene SRY, which triggers male development. The DNA in the human Y chromosome is composed of about 62 million base pairs, making it similar in size to chromosome 19.
KaryotypeA karyotype is the general appearance of the complete set of chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. Karyotyping is the process by which a karyotype is discerned by determining the chromosome complement of an individual, including the number of chromosomes and any abnormalities. A karyogram or idiogram is a graphical depiction of a karyotype, wherein chromosomes are generally organized in pairs, ordered by size and position of centromere for chromosomes of the same size.
Child abuseChild abuse (also called child endangerment or child maltreatment) is physical, sexual, and/or psychological maltreatment or neglect of a child or children, especially by a parent or a caregiver. Child abuse may include any act or failure to act by a parent or a caregiver that results in actual or potential harm to a child and can occur in a child's home, or in the organizations, schools, or communities the child interacts with.
Child careChild care, otherwise known as day care, is the care and supervision of a child or multiple children at a time, whose ages range from two weeks of age to 18 years. Although most parents spend a significant amount of time caring for their child(ren), child care typically refers to the care provided by caregivers that are not the child's parents. Child care is a broad topic that covers a wide spectrum of professionals, institutions, contexts, activities, and social and cultural conventions.
ChildA child (: children) is a human being between the stages of birth and puberty, or between the developmental period of infancy and puberty. It may also refer to an unborn human being. The legal definition of child generally refers to a minor, otherwise known as a person younger than the age of majority. Children generally have fewer rights and responsibilities than adults. They are classed as unable to make serious decisions.
