DNA Shape/Structure

Question 1

Watson and Crick

Answer 1

• discovered that DNA is a double-helix, in which tow strands are wrapped around each other (twisted ladder)
• the twisted nature conserves space
• DNA is polymer
• backbone of the DNA chain is formed by the sugar and phosphate groups of each nucleotide
• the nitrogenous bases stick out and connect in the middle

Question 2

Nucleotides

Answer 2

• the monomer
• has three major components:
• 5-carbon sugar deoxyribose (DNA)
• phosphate group: these first two make up the sides of the ladder (the backbone of DNA)
• Nitrogenous bases: the steps of the ladder, purines, pyrimidines

Question 3

base-pairing

Answer 3

• one purine and one pyrimidine

- bonds in DNA can only form between adenine and thymine (A-T) and between guanine and cytosine (G-C)

Question 4

hydrogen bonds

Answer 4

• hold the two strands (sides) of the double helix (ladder) together
• these bonds are sturdy enough to hold things together but breakable when needed

Question 5

purines

Answer 5

• nucleotides with 2 rings
• Adenine
• Guanine

Question 6

pyyrimidines

Answer 6

• nucleotides with 1 ring
• Thymine
• Ctyosine