Difference Between Chromatin and Chromosomes, Major Differences

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Difference Between Chromatin and Chromosomes Table

What is Chromatin? 

• Nucleosomes: The fundamental unit of chromatin is the nucleosome, which consists of approximately 146 base pairs of DNA wrapped around a core of eight histone proteins. Histones play a crucial role in maintaining the structure of chromatin and influencing its accessibility.
• Structural Organization: Chromatin is not a uniform structure but exists in different states of compaction. It can be classified into euchromatin and heterochromatin. Euchromatin is less condensed and associated with active gene transcription, while heterochromatin is more condensed and often contains silenced or inactive genes.
• Gene Regulation: The structure of chromatin influences the accessibility of genes to cellular machinery. Changes in chromatin structure, such as modifications to histone proteins or DNA methylation, can regulate gene expression.
• Cell Division: During cell division, chromatin undergoes dynamic changes. Prior to cell division, chromatin condenses further to form visible structures known as chromosomes. This process ensures the accurate distribution of genetic material to daughter cells.

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What are Chromosomes?

• DNA Packaging: Chromosomes are formed by the further condensation of chromatin, which is a complex of DNA and proteins. The DNA in chromosomes is highly condensed and organized, allowing it to fit within the limited space of the cell's nucleus.
• Genetic Information: Chromosomes carry genes, which are segments of DNA that encode instructions for the synthesis of proteins. These genes determine the traits and characteristics of an organism. Humans, for example, have 23 pairs of chromosomes, with one set inherited from each parent.
• Homologous Pairs: In sexually reproducing organisms, chromosomes are present in pairs, with one member of each pair inherited from each parent. These pairs are called homologous chromosomes. While they carry genes for the same traits, variations in the actual genes (alleles) may exist between homologous chromosomes.
• Cell Division: Chromosomes play a crucial role in cell division. Before cell division occurs, the chromosomes replicate, resulting in two identical chromatids held together by a structure called the centromere. During cell division, chromosomes separate, and each daughter cell receives a complete set of chromosomes.
• Species-Specific: The number and structure of chromosomes vary among species. For example, humans have 46 chromosomes (23 pairs), while dogs have 78 chromosomes, and fruit flies have 8 chromosomes.
• Karyotype: The arrangement and visual representation of an organism's chromosomes are called its karyotype. Karyotyping is a valuable tool in genetics for studying chromosomal abnormalities and variations.