Chromosome

Definition

A chromosome is a long, thread-like structure made of DNA and proteins that contains genetic information. It is critical in ensuring the proper segregation of genetic material during cell division, playing a key role in both inheritance and genetic variation.

5 Must Know Facts For Your Next Test

1. In eukaryotic cells, chromosomes are located in the nucleus and exist as linear structures, while in prokaryotic cells, they typically exist as a single circular chromosome.
2. Humans have 46 chromosomes, arranged in 23 pairs, with one chromosome of each pair inherited from each parent.
3. During cell division, chromosomes undergo replication and condensation, allowing them to be easily segregated into daughter cells.
4. Chromosomal abnormalities can lead to genetic disorders and diseases, such as Down syndrome, which is caused by an extra copy of chromosome 21.
5. The structure of chromosomes includes regions called centromeres and telomeres, which play important roles in chromosome stability and cell division.

Review Questions

• How do the structures of chromosomes differ between prokaryotic and eukaryotic cells, and why are these differences significant?
  • Prokaryotic cells typically have a single circular chromosome that is not enclosed within a nucleus, while eukaryotic cells contain multiple linear chromosomes housed within a membrane-bound nucleus. These structural differences are significant because they affect how genetic information is organized and accessed during processes such as replication and transcription. The compartmentalization in eukaryotic cells allows for more complex regulation of gene expression compared to prokaryotes.
• Discuss the role of chromosomes in Mendel's experiments on inheritance and how they contributed to our understanding of genetic traits.
  • Mendel's experiments laid the groundwork for understanding inheritance patterns through his work with pea plants. He identified that traits are passed down through discrete units, now known as genes, which are located on chromosomes. This connection helped establish the laws of inheritance, where the segregation and independent assortment of chromosomes during meiosis contribute to genetic variation among offspring. Mendel's findings were pivotal in linking observable traits to chromosomal behavior during reproduction.
• Evaluate the impact of chromosomal abnormalities on genetic inheritance and their implications for human health.
  • Chromosomal abnormalities can significantly affect genetic inheritance by altering the normal number or structure of chromosomes. For instance, conditions such as aneuploidy result from abnormal numbers of chromosomes and can lead to developmental issues or genetic disorders like Down syndrome. The implications for human health are profound as these abnormalities can disrupt normal cellular functions and contribute to diseases, emphasizing the importance of chromosomes in maintaining genetic stability and diversity within populations.

Related terms

DNA: Deoxyribonucleic acid, the molecule that carries the genetic instructions for life.

Gene: A segment of DNA that contains the instructions for building a specific protein or function.

Chromatid: One half of a duplicated chromosome, which is joined to its sister chromatid by a centromere.