Chromosomes are made of long aggregates of genes formed from condensed chromatin. Chromatin is made up of DNA, proteins, RNA and other macromolecules. It is located in the nucleus of a cell and becomes a chromosome during the prophase stage of mitosis in eukaryotic cell division.Know More
One of the main functions of chromatin is to reduce the size of DNA so it can fit in the cell. It does this by wrapping a DNA molecule tightly around proteins called histones. The histones are there to maintain the structure of the chromosome. Other functions of chromatin include reinforcing DNA molecules for mitosis, preventing DNA damage, and helping to control DNA replication.
A fully formed chromosome is made up of two chromatin sections that join together at a central point called the centromere. One of the chromatin sections, or arms, is generally shorter than the other. The shorter section is referred to as the "p arm" of the chromosome, and the longer section is called the "q arm."
Before cell division occurs, chromosomes cannot be seen inside the nucleus, even with the help of a microscope. It is only during cell division that the DNA becomes compact enough to be observed, so most of what scientists know about chromosomes comes from observing cell division.Learn more in Molecular Biology & DNA
An extra chromosome can cause a variety of birth defects, depending on which chromosome is affected, causing disorders such as Down syndrome and Edwards syndrome. In order to be born with an extra chromosome, one pair of chromosomes must have an extra chromosome attached to it, called a trisomy.Full Answer >
Genes that occur at the same place on the chromosome but occur in different forms are called alleles. Alleles are essentially different versions of a gene, and they can cause dissimilarities in an organism's function or structure. An example is the gene responsible for melanin production in most animals. One version of this gene causes the organism to produce adequate melanin, while the other allele prevents melanin from being produced.Full Answer >
A gene is a specific location on a chromosome that codes for a particular protein. Alleles are variants of a gene that determine how the protein looks.Full Answer >
Specialized transduction happens when only specific regions of the chromosome are transduced. This is different than generalized transduction, where any part of the chromosome can be transduced. Transduction is the transfer of genetic material from one bacterial cell to another using a bacteriophage.Full Answer >