* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Protein Synthesis Section 3 Transcription and Translation
Protein moonlighting wikipedia , lookup
History of genetic engineering wikipedia , lookup
RNA interference wikipedia , lookup
Cell-free fetal DNA wikipedia , lookup
Cre-Lox recombination wikipedia , lookup
Extrachromosomal DNA wikipedia , lookup
Nucleic acid double helix wikipedia , lookup
Vectors in gene therapy wikipedia , lookup
Non-coding DNA wikipedia , lookup
RNA silencing wikipedia , lookup
Polyadenylation wikipedia , lookup
Therapeutic gene modulation wikipedia , lookup
Frameshift mutation wikipedia , lookup
Nucleic acid tertiary structure wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
Point mutation wikipedia , lookup
History of RNA biology wikipedia , lookup
Deoxyribozyme wikipedia , lookup
Transfer RNA wikipedia , lookup
Non-coding RNA wikipedia , lookup
Messenger RNA wikipedia , lookup
Nucleic acid analogue wikipedia , lookup
Primary transcript wikipedia , lookup
Expanded genetic code wikipedia , lookup
Watson and Crick discovered the structure of DNA, but what remained a mystery is how DNA served as a genetic code for the making of proteins. Animation DNA has genes that code for the synthesis (creation) of specific PROTEINS Here’s the problem… Where is DNA located? Nucleus Where does Protein Synthesis occur? At ribosomes in the cytoplasm Can DNA ever leave the nucleus? No. DNA Structure: Double stranded RNA Structure: Single-stranded Sugar: Deoxyribose Sugar: Ribose Bases: Adenine Guanine Cytosine Thymine Bases: Adenine Guanine Cytosine Uracil Ribonucleic acid Single-stranded Sugar is ribose Thymine is replaced by URACIL 3 major types in living cells 1) Messenger RNA (mRNA) o carries information from DNA to ribosome 2) Transfer RNA (tRNA) o Carries amino acids to ribosome to make protein 3) Ribosomal RNA (rRNA) o Makes up ribosomes; site of protein synthesis. o located on Rough ER and in cytoplasm RNA can be Messenger RNA Ribosomal RNA which functions to also called mRNA Carry instructions also called which functions to rRNA Combine with proteins from to to make up DNA Ribosome Ribosomes Transfer RNA also called which functions to tRNA Bring amino acids to ribosome TRANSCRIPTION – the synthesis of RNA under the direction of DNA TRANSLATION – the actual synthesis of a protein, which occurs under the direction of mRNA From DNA to RNA Where is the DNA? location= nucleus RNA polymerase runs along DNA strand in nucleus and makes RNA (mRNA) mRNA = messenger RNA (sends message outside of nucleus) mRNA leaves nucleus through a nuclear pore and meets up with a ribosome (rRNA) in the cytoplasm From RNA to Protein Where is the DNA? Protein synthesis – the manufacture of proteins Where are proteins made in the cell? location= ribosome in cytoplasm Once mRNA is at a ribosome (rRNA), amino acids are assembled to make proteins Transfer RNA (tRNA) brings the appropriate amino acid to the growing protein chain Genetic code – the language of mRNA instructions (blueprints) Read in three letters at a time Each letter represents one of the nitrogenous bases: A, U, C, G Codon found on mRNA; consists of three bases (one right after the other) 64 codons for 20 amino acids mRNA carries the codon (three base sequence that codes for an amino acid) tRNA carries the anticodon which pairs up with the codon tRNA brings the correct amino acid by reading the genetic code For example, consider the following RNA sequence: UCGCACGGU The sequence would be read three base pairs at a time: UCG – CAC – GGU The codons represent the amino acids: Serine – Histidine - Glycine AUG – start codon or Methionine UAA, UAG, UGA – stop codons; code for nothing; like the period at the end of a sentence Amino acids link together to form a protein The new protein could become cell part, an enzyme, a hormone etc. CODON ANTI CODON Say the mRNA strand reads: mRNA (codon) AUG–GAC–CAG-UGA tRNA (anticodon) UAC-CUG-GUC-ACU tRNA would bring the amino acids: Methionine-Aspartic acid-Glutamine-stop SUMMARY 1)mRNA is transcribed in the nucleus and leaves the nucleus to the cytoplasm 2) mRNA attaches to the ribosome 3) The codon on the mRNA is read by the anticodon on the tRNA 4) tRNA brings the amino acid as it reads mRNA 5) The amino acids are joined together to form a polypeptide (protein) 6) When a stop codon is reached (UAA, UAG, UGA) protein synthesis stops MUTATION!!! If transcription or translation were to copy the wrong sequence, the incorrect amino acid could be added This would change the overall protein structure and could make the protein ineffective Example: Sickle cell anemia is caused by a single amino acid difference in the hemoglobin protein sequence Point Mutations – only occur at a single point in the DNA sequence – only changes a few amino acids Frameshift Mutations – shift the entire “reading frame” – change ALL the amino acids Substitution – one base replaces another Insertion – an extra base is inserted Deletion – loss of a single letter (makes entire base disappear!) Substitution Insertion Deletion Change in the number or structure of chromosomes Ex. – Deletion, Duplication, Inversion, and Translocation Deletio n Duplication Inversion Translocation