DNA Structure

Question 1

DNA structure overview

Answer 1

made of two linked strands that wind around each other to resemble a twisted ladder — a shape known as a double helix. Each strand has a backbone made of alternating sugar (deoxyribose) and phosphate groups. Attached to each sugar is one of four bases: adenine (A), cytosine (C), guanine (G) or thymine (T).

Question 2

DNA Molecules are

Answer 2

Polymer

Question 3

What bases are connected together

Answer 3

cytosine and guanine
adenine and thymine

Question 4

Step 1

Answer 4

The first thing we see is an unzippered strand of DNA with the Topoisomerase around it. The Topoisomerase straightens the DNA so it can be split.

Question 5

Step 2

Answer 5

The Helicase opens up and splits the DNA. The Helicase is an enzyme that unwinds the double helix by breaking the hydrogen bonds. The splitting of the DNA is what leads to the replication process.

Question 6

Step 3

Answer 6

After the DNA is split, single strand binding proteins coat the DNA around the split strands and prevent the dna molecules- adenine, thymine, guanine and cytosine- from coming together.

Question 7

Step 4

Answer 7

The primase makes short strands of RNA Primase that binds to the DNA Strand to initiate synthesis. This enzyme only works in the 5’ to 3’ direction, so the strand is replicated continuously. Leading( 3’-5’) and Lagging Strands (5’-3’).

Question 8

Step 5

Answer 8

DNA Polymerase III
The DNA Polymerase III lands on a primer and works backward in a 5’-3’ direction. It adds in new base pairs and nucleotides.

Question 9

Okazaki Fragments

Answer 9

These fragments are formed in the lagging strand.

Question 10

Step 6

Answer 10

On the lagging strand Okazaki Fragments are fixed by a ligase. The gap is fixed by the ligase. Ligase steals sugar phosphate backbones.