Question

6. What holds the sides of the DNA ladder together? 7. What are the sides of the DNA ladder made of? 8. What three parts make up a single nucleotide?

Answer 1

6. Hydrogen bonds formed by complementary base pairs holds the sides of the DNA ladder together.

There are two hydrogen bonds present between adenine and thymine base pair and three hydrogen bonds present between guanine and cytosine. The two DNA strands are held together by this hydrogen bond.See the image below -

P= Phosphate bond ss Sugar 5 3 Two hydrogen bonds -AT- 3 Hydrogen Bonds GEC A= Adenine T= Thymine Ge= Geuanine c = Cytosine 5-A=7 fig - DNA. (Simplified) 5 3

7. Sides of the DNA ladder is made of Nucleotides.

DNA strands are nothing but polynucleotides. Neucleotides are composed of a nitrogen base, a pentose sugar and a phosphate.

8. The three parts that make up a single nucleotide are :

A. A nitrogen base ( Adenine, guanine, thymine , cytosine)

B. A pentose sugar ( Sugar containing 5 carbon atoms)

C. A phosphate.