Nucleic Acids: DNA & RNA Structure

Nucleic Acids: DNA & RNA Structure and Function

• Nucleic acids are linear polymers
• They store and pass genetic information

Nucleotide Structure

• Nucleotides are the building blocks
• Each nucleotide contains a phosphate group, a sugar (deoxyribose in DNA, ribose in RNA), and a nitrogenous base
• Nitrogenous bases include purines (adenine, guanine) and pyrimidines (cytosine, thymine in DNA, uracil in RNA)

DNA Structure

• DNA is a double helix
• Two antiparallel strands wound around each other
• The strands are held together by hydrogen bonds between complementary nitrogenous bases (A with T, and G with C)
• DNA has a sugar-phosphate backbone

RNA Structure

• RNA is typically single-stranded
• The sugar in RNA is ribose
• The nitrogenous base uracil replaces thymine in RNA
• Several types of RNA exist including mRNA, tRNA, and rRNA
• Several other non-coding RNAs function in gene regulation

Chargaff's Rule

• In DNA, the amount of adenine equals the amount of thymine, and the amount of guanine equals the amount of cytosine

DNA Packaging

• DNA is packaged into structures called chromosomes
• DNA wraps around proteins called histones to form nucleosomes
• Further packaging coils the nucleosomes into a tightly packed structure

Central Dogma

• DNA -> RNA -> Protein
• DNA replication makes copies of DNA
• Transcription converts DNA to RNA
• Translation converts RNA to protein

Types of RNA

• mRNA - carries the genetic code for protein synthesis
• tRNA - carries amino acids to the ribosome
• rRNA - forms the ribosome structure
• Other Types: snRNA (small nuclear RNA), snoRNA (small nucleolar RNA), miRNA (microRNA), siRNA, lncRNA (long non-coding RNA), and circRNA (circular RNA)

Gene Structure

• Genes are segments of DNA that code for proteins
• A gene contains an exon (region coding for protein) and intron (region not coding for protein)

Transcription

• Transcription is the process of making RNA from DNA
• RNA polymerase synthesizes RNA
• It proceeds in 3 stages: Initiation – Elongation – Termination

Translation

• Translation is the process of making protein from mRNA
• mRNA is read by ribosomes
• tRNA brings amino acids to the ribosome
• Amino acids are linked together to form a polypeptide chain
• The polypeptide chain folds into a functional protein

Gene and DNA - Differences

• Gene is a sequence of DNA or RNA that codes for a functional product
• DNA is a molecule composed of two strands forming a double helix carrying the genetic instructions needed in the growth, development, and functioning of all living organisms

Explore the fundamental concepts of nucleic acids, including the structure and function of DNA and RNA. Learn about the crucial role of nucleotides, the double helix formation of DNA, and the different types of RNA involved in gene expression. This quiz will test your understanding of these essential biological molecules.