Very very easy question about size of macromolecules?

[scilearner]

Hello guys,

 

I have a very quick question. They say nucleic acids are very large molecules and they cover some large distance I can not remember. Are they saying the length of these molecules are long or the size(meaning they are big with width). I don't understand how they can fit in a cell if they are that big. I can understand how they can wind a lot inside a cell, but that only explains the length. It is those trivia like things where they say this can cover the size of a tennis court and such things. Just give me your opinion. Thanks

[Greippi]

DNA is very long but very thin (around 2.6nm wide). The largest human chromosome is roughly 72 centimeters long if you completely unwound it, but kept it as a double helix (it's 220 million base pairs - each nucleotide is around 0.33nm long). We have 22 pairs of chromosomes.

 

In the cell, the genetic material is VERY tightly wound up in to the chromosome structures - which include bead-like proteins called histones.

[scilearner]

DNA is very long but very thin (around 2.6nm wide). The largest human chromosome is roughly 72 centimeters long if you completely unwound it, but kept it as a double helix (it's 220 million base pairs - each nucleotide is around 0.33nm long). We have 22 pairs of chromosomes.

 

In the cell, the genetic material is VERY tightly wound up in to the chromosome structures - which include bead-like proteins called histones.

 

Thanks Greippi, that's what I was thinking but you confirmed it. I have one quick question. When the DNA is double stranded, does that mean it has 2 separate helixes joined, or one long helix interwined to make 2 helixes. What I mean if it is former if you are unwinding the DNA helix, you have to keep one dna strand under the other dna strand to find the length, if the 2 dna strands are separate. I hope you understand what I mean. Thanks

[Greippi]

Double stranded as in 2 strands make up one helix.

 

Just like this:

 

See, two sets of sugar/phosphate backbones.

[CharonY]

Normally when someone says that a molecule is large they refer to its molecular weight.