Nucleic acids

Question 1

The building blocks of nucleic acids

Answer 1

Nucleotides, that are consisted of:

1. Five carbon sugar – ribose (𝑂𝐻 on Carbon 2) of deoxyribose (𝐻 on carbon 2)
2. Nitrogenous base – attached to Carbon 1
3. Phosphide group attached to carbon 5

• Nucleoside – sugar + base with no phosphate.

**Nucleotides are linked together by phosphodiester bonds.

Question 2

Nitrogenous Bases

Answer 2

A nitrogenous base, or nitrogen-containing base, is an organic molecule with a nitrogen atom that has the
chemical properties of a base. The main biological function of a nitrogenous base is to bind nucleic acids
together. A nitrogenous base owes its basic properties to the lone pair of electrons of a nitrogen atom.

Question 3

Types of Nitrogenous bases

Answer 3

Nitrogenous bases are divided into two group:

1. Purines: Consists of two rings with four nitrogens.
   - –(Adenine and Guanin)
2. Pyrimidines: Consist of one ring with two
   nitrogens.
   - –(Uracil [for 𝑅𝑁𝐴], Thymine [for 𝐷𝑁𝐴] and Cytosine)

Question 4

𝐷𝑁𝐴 and the 𝑅𝑁𝐴 languages have the letters:

Answer 4

DNA:

• Adenine
• Cytosine
• Thymine
• Guanin

RNA:

• Adenine
• Ctyosine
• Uracil
• Guanin

Question 5

𝑫𝑵𝑨 is

Answer 5

The 𝐷𝑁𝐴 composes the hereditary material of an organism. In each cell, there are forty-six 𝐷𝑁𝐴 molecules; each one is tightly packed in the structure chromosome. Each chromosome is composed of
many genes. One gene equals one protein. The forty-six chromosomes are basically twenty-two pairs; any
one of which comes from each parent.

Question 6

DNA structure

Answer 6

the 𝐷𝑁𝐴 is a double helix: two chains of nucleotides held together by hydrogen bonds with the nitrogen bases facing each other, creating base pairs: 𝐴(Adenine) facing 𝑇(Thymine), and 𝐶(Cytosine) facing 𝐺(Guanine). The two chains are antiparallel – run in opposite directions.

**The total purine content of 𝑫𝑵𝑨 is always equal to the pyrimidine content.

Question 7

RNA is

Answer 7

The 𝑅𝑁𝐴 carries out 𝐷𝑁𝐴 instructions by transferring 𝐷𝑁𝐴 information to the site of protein production(ribosomes). It is also responsible for translating 𝑅𝑁𝐴 into protein, and for gene expression
regulation.

Question 8

RNA structure

Answer 8

Usually exists as a single chain of pairs: 𝐴(Adenine) facing 𝑈(Uracil), and 𝐶(Cytosine) facing 𝐺(Guanine).

Question 9

Types of 𝑅𝑁𝐴:

Answer 9

1. 𝑚𝑅𝑁𝐴 – a copy of a gene that transports the information from the nucleus to the ribosomes.
2. 𝑟𝑅𝑁𝐴 – composes ribosomes sites of protein production.
3. 𝑡𝑅𝑁𝐴 – translates the nucleic acid language to amino acid language.
4. 𝑛𝑐𝑅𝑁𝐴 (noncoding 𝑅𝑁𝐴) – 𝑅𝑁𝐴 molecules that have a regulatory role.