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Chromosome: a long, thread-like molecule made of the chemical called DNA (deoxyribonucleic acid) that is held together with special proteins and is visible (with strong microscopes) during cell division... more
Gene: a region of DNA that instructs the cell on how to build protein(s). As a human, you usually get a set of instructions from your mom and another set from your dad... more
Karyotype: an image of chromosomes which shows their shape, size, and number.
Chromosomes and Genes
Take a moment to consider how traits are passed from parent to offspring inside the cell. The information for the traits of an organism is stored in DNA, as genes on chromosomes. All living things have genes and chromosomes. Depending on the plant or animal, the size and number of chromosomes are different. Think of chromosomes as giant set of instructions for living things.
Chromosomes Two-By-Two
Chromosomes come in matching pairs, one pair from each parent. Humans, for example, have a total of 46 chromosomes, 23 from the mother and another 23 from the father. With two sets of chromosomes, children inherit two copies of each gene, one from each parent.
The image below, call a karyotype, shows the chromosomes of a human, lined up in pairs. The only two chromosomes that do not always come in matching pairs are the sex chromosomes, X and Y. In humans, girls have two matching X chromosomes. Boys, however, have a Y chromosome and only one X chromosome. By looking at the sex chromosomes in the image below, we can tell that the person this karyotype belongs to is male.
References
Additional images and illustrations from Wikimedia. Ant picture taken by en:User:Ways
View Citation
Bibliographic details:
- Article: Chromosomes and Genes
- Author(s): Sabine Deviche
- Publisher: Arizona State University School of Life Sciences Ask A Biologist
- Site name: ASU - Ask A Biologist
- Date published: July 20, 2010
- Date accessed: January 12, 2025
- Link: https://askabiologist.asu.edu/chromosomes-and-genes
APA Style
Sabine Deviche. (2010, July 20). Chromosomes and Genes. ASU - Ask A Biologist. Retrieved January 12, 2025 from https://askabiologist.asu.edu/chromosomes-and-genes
Chicago Manual of Style
Sabine Deviche. "Chromosomes and Genes". ASU - Ask A Biologist. 20 July, 2010. https://askabiologist.asu.edu/chromosomes-and-genes
Sabine Deviche. "Chromosomes and Genes". ASU - Ask A Biologist. 20 Jul 2010. ASU - Ask A Biologist, Web. 12 Jan 2025. https://askabiologist.asu.edu/chromosomes-and-genes
MLA 2017 Style
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