Can you answer these 3 biology questions?

1.You can find the dna structure in 12th class ncert book (ch.6 fig.6.2) or on the following link:

http://schools.aglasem.com/?p=18711

2Here is the structure of four nucleotides:

http://t3.gstatic.com/images?q=tbn:ANd9GcSWGvjGCYs...

3.Certain bases pair to each other only due to base pair specificity. Adenine double bonds with thymine while guanine triple bonds with cytosine. This maintains the shape & size of dna double helix.

1. Draw and label a flat section of dna including at least four base pairs

draw a line in the floor from wall to wall so that will take care of the flat part ,then either take a dump or pee in four pair of shoes and that will take care of the DNA.

2. Draw and label the four nucleotides

Just take the labels off food cans or beer bottle so you dont have to draw and write "nucleotides" four times.

3. Explain why certain bases only pair to each other?

because if they are not pairs then they are singles.

I think this web site can help you

For #2, you can google search 4 nucleotide, which are A T G C (or you can see in the website below)

# 3 A-T and G-C base pairs are the same length, and occupy the same space within a DNA double helix. Therefore the DNA molecule has a uniform diameter.