Chromosomes

Definition

Chromosomes are DNA molecules that contain the genetic instructions for the development, functioning, growth, and reproduction of all known organisms. They are highly structured and organized within the nucleus of cells.

5 Must Know Facts For Your Next Test

1. Humans have 46 chromosomes arranged in 23 pairs.
2. Chromosomes are made up of chromatin, which is a combination of DNA and proteins called histones.
3. During cell division, chromosomes condense to become more visible under a microscope.
4. Each chromosome has a centromere, which is essential for the movement of chromosomes during cell division.
5. Mutations or abnormalities in chromosome number or structure can lead to genetic disorders.

Review Questions

• How many chromosomes do humans typically have?
• What role do histones play in the structure of chromosomes?
• Why is the centromere important during cell division?

Related terms

DNA:

The molecule that carries genetic information necessary for life.

Histones:

Proteins around which DNA winds to form chromatin.

Centromere: A region on a chromosome that links sister chromatids during mitosis or meiosis.