Chromosomes

Prokaryotic and Eukaryotic Chromosomes

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Prokaryotic and Eukaryotic Chromosomes

The genome of an organism encompasses all of the genes of that organism. Gene is a distinct sequence of nucleotides forming part of a chromosome, the order of which determines the order of monomers in a polypeptide or nucleic acid molecule. Thus a protein-coding gene is defined as a region of DNA that encodes a single polypeptide or a set of closely related polypeptides. Genes are contained in chromosomes. Chromosomes are thus structures within cells that contain hundreds to thousands … Read more

Nucleus- Definition, Structure, Functions and Diagram

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Nucleus- Structure and Functions

Nucleus Definition The cell nucleus​ is a membrane-bound structure that contains the cell’s hereditary information and controls the cell’s growth and reproduction. It is the command center of a eukaryotic cell and is commonly the most prominent organelle in a cell accounting for about 10 percent of the cell’s volume. In general, a eukaryotic cell has only one nucleus. However, some eukaryotic cells are enucleated cells (without a nucleus), for example, red blood cells (RBCs); whereas, some are multinucleate (consists of two or more … Read more

Chromosome- Structure, Types and Functions

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Chromosome- Structure, Types and Functions

In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes. Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure. Chromosomes were first described by Strasburger (1815), and the term ‘chromosome’ was first used by Waldeyer in 1888. They appear as rod shaped dark stained bodies during the metaphase stage of mitosis when cells are stained with a suitable basic dye and viewed under a … Read more

Chromosomes- Abnormalities and Disorders

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Chromosomes- Abnormalities and Disorders

Chromosomes refer to any of the rod-shaped or threadlike DNA-containing structures of cellular organisms that are located in the nucleus of eukaryotes, are usually ring-shaped in prokaryotes (such as bacteria), and contain all or most of the genes of the organism. Simply put, it is a strand of DNA that is encoded with genes. Chromosomes are important because they contain the entire (or at least the vast majority of) genetic information for an organism. The Human Chromosomes Every normal human cell, except for … Read more

Yeast Artificial Chromosomes (YACs)

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Yeast Artificial Chromosomes (YACs)

Yeast artificial chromosomes (YACs) are genetically engineered chromosomes derived from the DNA of the yeast. It is a human-engineered DNA molecule used to clone DNA sequences in yeast cells. They are the products of a recombinant DNA cloning methodology to isolate and propagate very large segments of DNA in a yeast host. By inserting large fragments of DNA, the inserted sequences can be cloned and physically mapped using a process called chromosome walking. The amount of DNA that can be cloned … Read more