Nucleic Acids

Question 1

What is the Central Dogma of Biology?

Answer 1

DNA -> RNA -> Protein -> Structures & Enzymes -> Functions -> Life

Question 2

What are Nucleic Acids?

Answer 2

Linear, unbranched polymers of nucleotides (polynucleotides)

Question 3

What are the components of Nucleotides?

Answer 3

• A Nitrogenous Base
• A 5 carbon sugar (pentose)
• A Phosphate

Question 4

Difference between a Nucleotide and a Nucleoside?

Answer 4

Nucleotides have a phosphate group present while nucleosides have no phosphate group present.

(nucleoside- only a nitrogenous base and a 5 carbon sugar)

Question 5

At which Carbon is the Phosphate group attached?

Answer 5

Carbon 5’

Question 6

At which carbon is the nitrogenous base attached?

Answer 6

Carbon 1’

Question 7

What are the two main types of nitrogenous bases?

Answer 7

Purines (Adenine and Guanine)
Pyrimidines (Cytosine, Thymine and Uracil)

Question 8

What are Purine bases?

Answer 8

-Two carbon-nitrogen ring bases
-Attached to C1 of pentose sugar at N9 to form nucleoside (C1->N9 linkage)
-Two types - Adenine (A) and Guanine (G)
-Found in both ribo- and deoxyribonucleotides

Question 9

What are Pyrimidine bases?

Answer 9

-One carbon-nitrogen ring bases
-Attaches to C1 of pentose sugar at N1 to form a nucleoside (C1->N1 linkage)
-Three types- Cytosine (C), Thymine (T) and Uracil (U)
- C is found in both ribo- and deoxyribonucleotides
- T is found in deoxyribonucleotides only
- U is found in ribonucleotides only

Question 10

What allows for specific base-pairing?

Answer 10

The formation of hydrogen bonds between amino and carbonyl groups and the available space inside the double helix structure for base interaction.

Question 11

Do bases absorb light? At which range?

Answer 11

Yes! Bases absorb light in the UV range at 260nm

Question 12

Flexibility of the Ring?

Answer 12

Note that the flexibility of the ring contributes to the flexibility of the nucleotides and nucleic acids.

Question 13

What are the types of nucleotides?

Answer 13

1. Ribonucleotides
2. Deoxyribonucleotides

Question 14

What type of bonds link nucleotides?

Answer 14

Phosphodiester bonds link nucleotides to form polynucleotides (bonds to the C5 of one nucleotide and C3 of the other nucleotide)

Question 15

Is the nucleotide/ nucleotide chain charged?

Answer 15

1. the strands have polarity; a 5’ and a 3’ end
2. the charges on the phosphodiester bonds (-ve charges)

Question 16

In what direction would you expect DNA to travel in an electric field?

Answer 16

From the -ve terminal to the +ve terminal.