DNA Structure

Question 1

What are the three components of a nucleotide?

Answer 1

A phosphate group, sugar molecule, and nitrogen base.

Question 2

What are the four nitrogenous bases found in DNA?

Answer 2

Adenine (A)
Guanine (G)
Cytosine (C)
Thymine (T)

Question 3

What is the base pairing rule?

Answer 3

Adenine (A) is with Thymine (T) in DNA.
Guanine (G) is with Cytosine (C) in DNA.

Question 4

Who was the scientist who discovered this base pairing rule (the rule is named after him)?

Answer 4

Erwin Chargaff

Question 5

What makes up the middle of the DNA molecule (the rungs of the ladder)?

Answer 5

Bases

Question 6

What 2 molecules make up the backbone of DNA (the sides of the ladder)?

Answer 6

Sugar and phosphate

Question 7

How many hydrogen bonds are present in between each base pair?

Answer 7

There are two hydrogen bonds between A and T

There are three between G and C

Question 8

How do you determine which end of a DNA strand is the 5’ end and which one is the 3’ end?

Answer 8

5’ End: This end has a phosphate group attached to the sugar. Picture the “5” as a flagpole with the phosphate group like a flag on top. So, it’s the start or the beginning of the DNA strand.

3’ End: This end has a hydroxyl (OH) group attached to the sugar. The “3” end is like the ending point, where there’s just a “3” hanging around (the OH group)

Question 9

What is meant by saying that the DNA strands are antiparallel?

Answer 9

they’re parallel (running side by side), but they’re going in opposite directions.