extra chromosomes in humans

In the diploid number, chromosomes are always found in pairs. In each pair there are two identical chromosomes, called homologous chromosomes. These chromosomes are identical in size, appearance and position of the centromere. Apart from this, the two homolog..

fig. 19.2 - Bacterial Chromosome In addition to the nucleoid, a bacterial cell may show the presence of extra chromosomal DNA molecules called plasmids. Like the bacterial chromosome, plasmids are double stranded circular DNA molecules which can replicate and..

As can be seen from the human karyogram, the chromosomes are classified into two types, autosomes and sex chromosomes. The autosomes have homologous chromosomes as pairs whereas the sex chromosomes are of two different types - X and Y. A female has..

It is a comprehensive international effort started in 1990 by molecular biologists to map the entire human genome by determining the complete nucleotide sequence of DNA of each chromosome..

>Culturing of human cells invitro, help in understanding the biochemical basis of inheritance. Human cytology and karyotyping helps in ascertaining the number, shape size and structural features of chromosomes. Study of monogygotic twins helps in distinguishing between..

It is well developed in reptiles, birds and prototherians. It is mainly digestive in function so it acts as an extra embryonic gut. In human beings it is vestigi..

uniduchat syndrome: loss of half of the short arm of chromosome 5 in human..

Chromosome number is a species-specific character. The complete set of chromosomes in the body cell of a species is known as karyotype. For example, the 23 pairs of chromosomes found in the somatic cells represent the human karyotyp..

Types of Cell Division - Cell division is a method by which new cells are originated from pre-existing cells. The formation of daughter amoebae in amoeba, the development of sex cells and the growth of a young animal or plant into an adult, all involve cell multiplication. In order to multiply in n..

Sex Determination - During the formation of gametes, the females will have only one type of gametes, all with one X chromosome. However, the males will produce two types of gametes or sperms, half with X chromosome and half with Y chromosome. Thus the sex of a zygote i..