Operation of DNA

 

DNA is one of the largest known molecules. If you

think of one molecule of sugar, a DNA molecule is

weighs 100,000 times more than that. In normal

weight (the way we normally think of things), a

DNA molecule is actually very light. Even one

quintillion DNA molecules weighs three ounces!

DNA molecules are cramped tightly inside the cells

that hold them because if they were completely

straight they would be several thousand times the

length of the cell!

DNA consists of two long thin strands that are

wound around each other to form a spiral. This is

called a double helix(check your dictionary for this

term!). The strands of a

double helix

are made up of a large amount of chemical building

blocks called bases.

Every strand of DNA contains about twelve billion

individual bases. Since there are four different types of

bases, A, G, C, and T, various sequences of different

arrangements of bases can

occur. The

strands of a helix are held together by

weak chemical bond between nearby

strands. The G base will

only pair up with the C base and the A base will only pair

up with the T base( for example, C can't pair with a G

base). So, if you put it all together, you have DNA.

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