RNA Ribonucleic Acid Structure of RNA Single stranded

RNA Ribonucleic Acid

Structure of RNA § § § Single stranded Ribose Sugar 5 carbon sugar Phosphate group Adenine, Uracil, Cytosine, Guanine

Types of RNA § Three main types § Messenger RNA (m. RNA) – delivers DNA code to ribosomes for translation. § Transfer RNA (t. RNA) – transfers amino acids to ribosomes for protein synthesis. § Ribosomal RNA (r. RNA) – Ribosomes are made of r. RNA and protein.

Transcription § RNA molecules are produced by copying part of the nucleotide sequence of DNA into complementary sequence in RNA, a process called transcription. § During transcription, RNA polymerase binds to DNA and separates the DNA strands. RNA polymerase then uses one strand of DNA as a template from which nucleotides are assembled into a strand of m. RNA.

The Genetic Code § § § This is the language of m. RNA. Based on the 4 bases of m. RNA. “Words” are the 3 RNA sequences called codons. The strand aaacguucgccc would be separated as aaa-cgu-ucg-ccc. The amino acids would then be Lysine – Arginine – Serine - Proline

Genetic Codes

Translation § During translation, the cell uses information from messenger RNA to produce proteins. 1. Transcription occurs in nucleus. 2. m. RNA moves to the cytoplasm then to the ribosomes. t. RNA “read” the m. RNA and obtain the amino acid coded for. 3. Ribosomes attach amino acids together forming a polypeptide chain. 4. Polypeptide chain keeps growing until a stop codon is reached.

Mutations § Gene mutations result from changes in a single gene. § Chromosomal mutations involve changes to whole chromosomes.

Gene Mutation § Point Mutation – Affects one nucleotide occurring at a single point on the gene. Usually one nucleotide is substituted for another nucleotide. § Frameshift Mutation – Inserting an extra nucleotide or deleting a nucleotide causes the entire code to “shift”.

Gene Mutation

Chromosomal Mutations § Deletion – part of a chromosome is deleted § Duplication – part of a chromosome is duplicated § Inversion – the chromosome twists excessively and inverts the code. § Translocation – genetic information is traded between two adjacent chromosomes.

Chromosomal Mutations