A basic question about DNA in a eukayotic cell?

Question

Are chromosomes in a nucleus interconnected by DNA strands? if i isolate the 46 chromosomes froma human cell and open it up will I get 46 separate DNA strands? If possible plz give the proof for the answer

Answer 1

Yes, each chromosome is a separate strand of double stranded DNA. (That is, it's one long double helix)

Look at a picture of a Karyotype or maybe some pictures of dividing cells in metaphase or telophase and you should be able to see the distinct chromosomes clearly. You can try google images, maybe. Also, during meiosis, (when cells divide to make a sperm or an egg) you get independent assortment of the chromosomes. This means that of each of the 23 pairs of chromosomes, the copy that you got from your mother will randomly go to one egg or sperm and the copy you got from your father will randomly go to the other, so each egg or sperm contains some chromosomes you got from your mother and some you got from your father. If you just had one long piece of DNA, that wouldn't work too well.

Answer 2

Chromosomes are not interconnected by DNA strands; each chromosome is a completely separate DNA molecule, and you WOULD get 46 separate strands if you isolated each chromosome (this kind of separation is called a karyotype and used to be done a lot, back in the day). I dunno what you want in terms of proof - this is a purely observational phenomenon.

Answer 3

DNA is made up of amino acids. Simply put, chromosomes are the structures that hold our genes. Genes are the individual instructions that tell our bodies how to develop and keep our bodies running healthy. In every cell of our body there are 50,000 to 100,000 genes that are located on 46 chromosomes. These 46 chromosomes occur as 23 pairs. We get one of each pair from our mother in the egg, and one of each pair from our father in the sperm. The first 22 pairs are labeled longest to shortest. The last pair are called the sex chromosomes labeled X or Y. Females have two X chromosomes (XX), and males have an X and a Y chromosome (XY). The average human chromosome has about 2.5 feet of DNA. If all the nucleotides of the human genome were actual letters (A,C,G,T) and these were printed, they would fill 4,000 books of 500 pages each. That is roughly 3 billion nucleotides. All of that stuff fits into a cell roughly 1 millionth of an inch wide. This is accomplished because the DNA is highly compacted in the cells. The basic unit of packaging is known as a nucleosome. It consists of 8 histones molecules that form a core plus DNA, which is wrapped around this nucleosome core. The nucleosomes are packaged into higher order structures packing all the DNA very tightly together.

Answer 4

A chromosome is composed of a super long strand of DNA, all coiled up. When you isolate the human chromosomes, you get 23 pairs of chromosomes, as shown in this web site:http://en.wikipedia.org/wiki/Human_genome. The pairs of chromosomes are usually held together by a centrosome, but they are separated during meiosis.

Answer 5

Yes, you'd get 46 separated strands of DNA called chromosomes. Separating these strands is called a karyotype. You can check it out in Wikipedia...

http://en.wikipedia.org/wiki/Karyotype