Nucleic Acids

Introduction to Nucleic Acids

Nucleic acids are essential biomolecules that store and transmit genetic information in all living organisms. The two main types of nucleic acids are DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). These molecules are composed of repeating units called nucleotides, which are linked together to form long chains.

• DNA: Stores genetic information and is found primarily in the cell nucleus.

• RNA: Involved in protein synthesis and gene regulation; found in the nucleus and cytoplasm.

• Nucleotides: The building blocks of nucleic acids, each consisting of a phosphate group, a five-carbon sugar, and a nitrogenous base.

Structure of Nucleic Acids

Nucleic acids are polymers made up of nucleotides. The structure of each nucleotide includes three components:

• Phosphate group: Provides the acidic character and links nucleotides together via phosphodiester bonds.

• Pentose sugar: Deoxyribose in DNA and ribose in RNA.

• Nitrogenous base: Divided into purines (adenine, guanine) and pyrimidines (cytosine, thymine in DNA; uracil in RNA).

The nucleotides are joined by phosphodiester bonds between the 3' carbon of one sugar and the 5' carbon of the next.

DNA vs. RNA

DNA and RNA differ in their structure, function, and location within the cell.

Nucleotides and Codons

Nucleotides are arranged in specific sequences to form codons, which are groups of three nucleotides that code for specific amino acids during protein synthesis.

• Codon: A sequence of three nucleotides in mRNA that specifies an amino acid.

• Genetic code: The set of rules by which information encoded in DNA or RNA sequences is translated into proteins.

Example: The codon AUG codes for the amino acid methionine and also serves as the start codon for translation.

Functions of Nucleic Acids in Cells

Nucleic acids play several critical roles in cellular processes:

• DNA replication: The process by which DNA makes a copy of itself during cell division.

• Transcription: The synthesis of RNA from a DNA template.

• Translation: The process by which ribosomes synthesize proteins using mRNA as a template.

Key Terms and Definitions

• Nucleotide: The monomer unit of nucleic acids, consisting of a phosphate, sugar, and base.

• Phosphodiester bond: The covalent bond linking nucleotides in a nucleic acid chain.

• Purines: Nitrogenous bases with a double-ring structure (adenine and guanine).

• Pyrimidines: Nitrogenous bases with a single-ring structure (cytosine, thymine, uracil).

Important Equations

The general structure of a nucleotide can be represented as:

The formation of a phosphodiester bond:

Additional info:

• Some content inferred from context and standard biology knowledge due to unclear handwriting and fragmented notes.

• "Crnonexithid" likely refers to "Nucleic Acid".

• "Deovyribanvele" interpreted as "Deoxyribonucleic acid (DNA)".

• "Nenes RA" interpreted as "Genes, RNA".