Chuni Panna Episode 31
What is a chromosome?
Chromosomes are thread-like structures locate inside the nucleus of animal and plant cells. Each chromosome is obtain of protein and a single molecule of deoxyribonucleic acid (DNA).
Prokaryotic cells (Bacteria) have one or tw circular chromosomes.
Eukaryotic organisms have linear chromosomes that are arranged in pairs within the nucleus of the cell.
Somatic cells (nonreproductive cells) have
Each chromosome is formed by two chromatids, held together by a narrow region called centromere
Each chromatid contains one molecule of
Chromatin is a complex of DNA and protein that condenses during cell division
There are two kinds of chromatin:
Loosely coiled, where active genes are locate HETEROCHROMATIN:
Tightly coiled, where inactive genes are locat
The Nucleus: Genetic Library of the Cell
Chromatin and Condensed Chromosome Structure
DNA Gene Gene
DNA and proteins are multi-folded
Mitotic chromosome condensation can thus be thought of as the final level in the hierarchy of chromosome packaging
Terms to remember
Chromatid/s e Chromatin Centromere Telomeres
Every eukaryotic species has a characteristic number of chromosomes I each cell nucleus
To study them, geneticists organice then in karyotypes (very useful to study genetic disorders, for instance)