Nucleic Acid Structure and Function

Nucleic Acid Structure and Function

• Nucleic acids are linear polymers that store and transmit genetic information.
• DNA and RNA are the two main types of nucleic acids.
• DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) differ in their sugar components (deoxyribose and ribose respectively).
• DNA is a double helix; RNA is usually single-stranded.

Nucleotide Structure

• Nucleotides are the building blocks of nucleic acids.
• Each nucleotide consists of a sugar, a phosphate group, and a nitrogenous base.
• The sugar in DNA is deoxyribose; in RNA, it is ribose.
• Nitrogenous bases are adenine (A), guanine (G), cytosine (C), and thymine (T) in DNA or uracil (U) in RNA.

DNA Structure

• DNA is a double helix with a sugar-phosphate backbone.
• The two strands are antiparallel, running in opposite directions (5' to 3' and 3' to 5').
• Nitrogenous bases pair specifically (A with T, G with C) via hydrogen bonds.

RNA Structure

• RNA, usually single-stranded, has a sugar-phosphate backbone.
• The nitrogenous bases pair similarly to DNA, but replacing Thymine (T) with Uracil (U).
• There are various types of RNA, each with specific functions.

Chargaff's Rule

• In double-stranded DNA, the amount of adenine (A) equals thymine (T), and the amount of guanine (G) equals cytosine (C).

DNA Packaging

• DNA is tightly packaged in cells using various levels of organization.
• DNA coils around histone proteins to form nucleosomes.
• Further packaging leads to higher levels of organization.
• This is important for DNA storage and function in the cell.

Types of RNA

• Specific types of RNA have different functions.
• mRNA carries genetic information for protein synthesis.
• tRNA carries amino acids for protein synthesis.
• rRNA is a component of ribosomes, sites of protein synthesis.
• There are other types of non-coding RNAs, participating in diverse processes.

Central Dogma

• The central dogma describes the flow of genetic information from DNA to RNA to protein.
• DNA replicates to create copies of itself.
• Transcription converts DNA into RNA.
• Translation converts RNA into protein.

Gene Structure

• A gene is a segment of DNA that codes for a specific polypeptide or protein.
• Genes have regulatory regions that control gene expression.
• Genes also have exons, which are coding regions, and introns, which are non-coding regions.
• The regions are important for gene function.

Transcription

• Transcription is the process of creating RNA from a DNA template.
• This starts at a specific region called the promoter.
• RNA polymerase is the enzyme that catalyzes this process making an RNA molecule.
• The complementary non-coding RNA is transcribed from the template strand of DNA.
• The sequence of bases in this non-coding RNA determines what amino acid will be incorporated in a protein.

Translation

• Translation is the process of converting RNA into protein.
• Ribosomes are the cellular structures that carry out translation.
• Specific tRNA molecules deliver amino acids to the ribosome based on the mRNA sequence.
• The tRNA sequence is complementary to the mRNA sequence.
• Amino acids are joined together by peptide bonds to form the polypeptide chain, and then folding to a protein.

Explore the fundamental aspects of nucleic acids, focusing on DNA and RNA, their structures, and functions. Understand the roles of nucleotides as building blocks and the significance of nitrogenous bases in genetic information storage and transmission.