Chromosomes: Morphology & Structure | Nucleosome | Grade 11 Biology | Federal Board Pakistan 2024 скачать в хорошем качестве

Chromosomes: Morphology & Structure | Nucleosome | Grade 11 Biology | Federal Board Pakistan 2024

Morphology of Chromosomes These are thread like structures only visible in dividing cells (mitotic phase). It's a thread like network, chromatin, during interphase. Typical chromosome consists of Chromatids Primary construction (centromeres) Secondary construction (NOR) Satellite DNA Junk DNA Telomeres Types Metacentric Submeta centric Acrocentric Telocentric Nucleosomes 1. *Definition*: Nucleosomes are the fundamental units of chromatin, consisting of DNA wrapped around a core of histone proteins. 2. *Structure*: A nucleosome consists of approximately 147 base pairs of DNA wrapped around a histone octamer. 3. *Function*: Nucleosomes play a crucial role in DNA packaging, gene regulation, and chromatin dynamics. Chromatin 1. *Definition*: Chromatin is the complex of DNA, histone proteins, and other non-histone proteins that make up chromosomes. 2. *Structure*: Chromatin is composed of nucleosomes, which are coiled into a higher-order structure called a chromatin fiber. 3. *Function*: Chromatin plays a crucial role in gene regulation, DNA replication, and repair. Chromatids 1. *Definition*: Chromatids are the identical sister strands of DNA that make up a chromosome. 2. *Formation*: Chromatids are formed during DNA replication, when the replicated DNA molecule is composed of two identical sister strands. 3. *Function*: Chromatids play a crucial role in the separation of chromosomes during cell division. Key Terms 1. *Centromere*: The region of a chromosome where the sister chromatids are attached. 2. *Telomeres*: The repetitive DNA sequences at the ends of chromosomes. 3. *Histone modifications*: Chemical modifications of histone proteins that influence chromatin structure and function. 1. #Chromosomes 2. #Genetics 3. #Biology 4. #DNA 5. #Genome 1. #ChromosomeStructure 2. #Chromatin 3. #Nucleosomes 4. #Chromatids #BiologyLesson #LearnBiology #GeneticsForBeginners