Ácidos nucleicos | Biología | Biomoléculas | V5 | Egg Educación

Understanding Nucleic Acids and Their Functions

Overview of Nucleic Acids

• Nucleic acids serve a dual purpose: they carry genetic information essential for cellular function and regulation, and they also act as energy carriers in the form of ATP or GTP.

Structure of Nucleotides

• The basic unit of nucleic acids is the nucleotide, which consists of three components: a phosphate group, a sugar (either deoxyribose or ribose), and a nitrogenous base.

• Nitrogenous bases are classified into purines (adenine and guanine) and pyrimidines (thymine, cytosine, uracil). This classification is crucial for understanding base pairing.

Formation of Polymers

• Nucleotides link together to form polymers; DNA consists of two antiparallel strands. Each strand's directionality is determined by the orientation of its sugar-phosphate backbone.

• The connection between nucleotides occurs through phosphodiester bonds formed between the phosphate group of one nucleotide and the 3' carbon atom of another's sugar.

Base Pairing Rules

• In DNA, complementary base pairing occurs: adenine pairs with thymine (two hydrogen bonds), while guanine pairs with cytosine (three hydrogen bonds).

• The antiparallel nature means that if one strand runs from 5' to 3', the opposite strand runs from 3' to 5', providing directional specificity.

Energy Storage in Nucleotides

• Triphosphate nucleotides like ATP store energy in their high-energy phosphate bonds; breaking these bonds releases energy necessary for metabolic processes.

• Hydrolysis of triphosphates results in diphosphates, releasing energy that can be utilized for various cellular functions.

Comparing DNA and RNA

Structural Differences

• DNA contains deoxyribose sugar while RNA contains ribose. Additionally, RNA has uracil instead of thymine found in DNA.

Functional Differences

• DNA typically exists as a double-stranded molecule whereas RNA usually exists as single-stranded. However, some viruses may contain double-stranded RNA.

Location within Cells