What is the threadlike structure within the nucleus containing genetic information called?

The threadlike structure within the nucleus that contains genetic information is called a chromosome. Chromosomes are made up of DNA and proteins, and they carry the genes that encode the traits and functions of an organism. During cell division, chromosomes become visible under a microscope as they condense from their less-visible chromatin form, allowing for the transmission of genetic information from one generation of cells to the next.

Each species has a characteristic number of chromosomes that contain all the genetic instructions necessary for growth, development, and reproduction. This structural organization is critical for processes such as cell division, where accurate replication and distribution of genetic material is essential for producing new cells.

While chromatids refer to the identical halves of a duplicated chromosome, and nucleotides are the building blocks of DNA, the genome encompasses the entire set of genetic material in an organism. In contrast, chromosomes are specific structures that represent portions of this genetic material. Thus, the term chromosome specifically denotes the threadlike structures that contain the genetic information.