RNA và cấu trúc phân tử, đặc tính sinh học

RNA RNA Ribonucleic Acid Ribonucleic Acid Structure of RNA Structure of RNA  Single stranded Single stranded  Ribose Sugar Ribose Sugar  5 carbon sugar 5 carbon sugar  Phosphate group Phosphate group  Adenine, Uracil, Cytosine, Guanine Adenine, Uracil, Cytosine, Guanine Types of RNA Types of RNA  Three main types Three main types  Messenger RNA Messenger RNA (mRNA) – transfers (mRNA) – transfers DNA code to ribosomes for translation. DNA code to ribosomes for translation.  Transfer RNA Transfer RNA (tRNA) – brings amino (tRNA) – brings amino acids to ribosomes for protein synthesis. acids to ribosomes for protein synthesis.  Ribosomal RNA Ribosomal RNA (rRNA) – Ribosomes are (rRNA) – Ribosomes are made of rRNA and protein. made of rRNA and protein. Transcription Transcription  RNA molecules are produced by copying part RNA molecules are produced by copying part of the nucleotide sequence of DNA into of the nucleotide sequence of DNA into complementary sequence in RNA, a process complementary sequence in RNA, a process called called transcription transcription . .  During transcription, RNA polymerase binds to During transcription, RNA polymerase binds to DNA and separates the DNA strands. RNA DNA and separates the DNA strands. RNA polymerase then uses one strand of DNA as a polymerase then uses one strand of DNA as a template from which nucleotides are template from which nucleotides are assembled into a strand of mRNA. assembled into a strand of mRNA. mRNA mRNA How Does it Work? How Does it Work?  RNA Polymerase looks for a region on RNA Polymerase looks for a region on the DNA known as a promoter, where it the DNA known as a promoter, where it binds and begins transcription. binds and begins transcription.  RNA strands are then edited. Some RNA strands are then edited. Some parts are removed ( parts are removed ( introns introns ) - which are ) - which are not expressed – and other that are left not expressed – and other that are left are called exons or expressed genes. are called exons or expressed genes. The Genetic Code The Genetic Code  This is the language of mRNA. This is the language of mRNA.  Based on the 4 bases of mRNA. Based on the 4 bases of mRNA.  “ “ Words” are 3 RNA sequences called Words” are 3 RNA sequences called codons codons . .  The strand aaacguucgccc would be The strand aaacguucgccc would be separated as aaa-cgu-ucg-ccc the amino separated as aaa-cgu-ucg-ccc the amino acids would then be Lysine – Arginine – acids would then be Lysine – Arginine – Serine - Proline Serine - Proline Genetic Codes Genetic Codes Translation Translation  During translation, the cell uses information During translation, the cell uses information from messenger RNA to produce proteins. from messenger RNA to produce proteins.  A – Transcription occurs in nucleus. A – Transcription occurs in nucleus.  B – mRNA moves to the cytoplasm then to the B – mRNA moves to the cytoplasm then to the ribosomes. tRNA “read” the mRNA and obtain ribosomes. tRNA “read” the mRNA and obtain the amino acid coded for. the amino acid coded for.  C – Ribosomes attach amino acids together C – Ribosomes attach amino acids together forming a polypeptide chain. forming a polypeptide chain.  D – Polypeptide chain keeps growing until a D – Polypeptide chain keeps growing until a stop codon is reached. stop codon is reached. Translation to Protein Translation to Protein . RNA Ribosomal RNA (rRNA) – Ribosomes are (rRNA) – Ribosomes are made of rRNA and protein. made of rRNA and protein. Transcription Transcription  RNA. Cytosine, Guanine Types of RNA Types of RNA  Three main types Three main types  Messenger RNA Messenger RNA (mRNA) – transfers (mRNA) – transfers DNA