* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Protein Synthesis
Butyric acid wikipedia , lookup
Transcriptional regulation wikipedia , lookup
List of types of proteins wikipedia , lookup
Polyadenylation wikipedia , lookup
Silencer (genetics) wikipedia , lookup
Protein adsorption wikipedia , lookup
Protein (nutrient) wikipedia , lookup
Cell-penetrating peptide wikipedia , lookup
Non-coding RNA wikipedia , lookup
Deoxyribozyme wikipedia , lookup
Peptide synthesis wikipedia , lookup
Gene expression wikipedia , lookup
Bottromycin wikipedia , lookup
Proteolysis wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
Messenger RNA wikipedia , lookup
Molecular evolution wikipedia , lookup
Protein structure prediction wikipedia , lookup
Epitranscriptome wikipedia , lookup
Nucleic acid analogue wikipedia , lookup
Biochemistry wikipedia , lookup
Protein Synthesis: The Central Dogma of Biology Chapter 8 in your textbook RNA: Ribonucleic acid Used to make proteins DNA RNA Thymine Uracil Double – stranded Single – stranded 1 type 3 types Deoxyribose sugar Ribose sugar Three Types of RNA Video clip – 2:52 1. mRNA (messenger): copies the information from the DNA to carry it out of the nucleus to the ribosomes 2. rRNA (ribosomal): used to make up most of the ribosomal subunits that decode the mRNA 3. tRNA (transfer): carries amino acids to the ribosome to be linked together to form an amino acid chain (that will become a protein) mRNA is linear (forms a line of bases) tRNA has a “cloverleaf” shape rRNA + protein make up the ribosome The Central Dogma of Biology DNA carries the genetic code (genes) The code is a triplet code – 3 nucleotides (grouped together as a codon) code for one amino acid. That code is translated into proteins (each gene codes for one protein) Each protein results in one trait (or is responsible for one part of one trait) Proteins result in the physical characteristics (traits) or enzymes (controls chemical reactions) of an organism Transcription: Making mRNA from DNA 1. One gene in the DNA molecule is opened Quick-time movie Transcription 2. RNA polymerase bonds free-floating RNA nucleotides to open bases on the exposed strand of DNA Animation Transcription Animation – Click on left hand box in top row 3.The newly made mRNA leaves the nucleus and travels to the ribosomes in the cytoplasm Translation: Making an amino acid chain from RNA -- Animation 1. The ribosomal subunits surround the mRNA Translation, cont’d 2. tRNA binds to a specific amino acid and brings it to a specific codon on the mRNA. One end of the tRNA has 3 bases called an anticodon that is complementary to the codon on the mRNA. Translation, cont’d 3. Amino acids are joined together by peptide bonds 4. tRNA is released and reused Protein Synthesis Video clip – 3:20 Animation The Genetic Code This chart is used to determine which amino acid will be added based on the mRNA codon. The Genetic Code, cont’d To find the amino acid that goes to a specific codon (three-base mRNA sequence), find the first base on the left, the second base across the top, and then – within that box – the third base on the right. Genetic Code, cont’d Sometimes the chart for translating mRNA codons into amino acids is displayed in a circular format The Genetic Code, cont’d There are 64 possible codons There are only 20 amino acids Each codon codes for one amino acid Ex: CCC codes for proline Some amino acids may be coded for by multiple codons Ex: CCU, CCC, CCA, and CCG all code for proline Video clip – 3:26 The Genetic Code, cont’d There is one “start” codon – AUG – which codes for the amino acid methionine There are three “stop” codons These codons do not code for any amino acid When a stop codon is reached, it is a signal that the amino acid chain is complete. This releases the amino acid – or polypeptide – chain Also, the mRNA detaches from the ribosome and the ribosomal subunits come apart Mutations Mutation = any error / mistake in the DNA Video clip – 1:47 Two types: point and frameshift Point mutations: those that affect one nucleotide – they occur at a single point on the DNA Point Mutations Substitution: changing one nucleotide for another May have no noticeable effect if the codon still codes for the same amino acid Point Mutation - Substitution May have a significant effect if the substituted codon changes the amino acid – video clip – 0:59 For instance, sickle cell anemia results from a single substitution point mutation The change of one nitrogen base leads to a different amino acid, causing the range of problems faced by a person with sickle cell anemia Deletions Deletion – removing one or more nucleotides If a set of three nucleotides is removed, then one amino acid will be missing from the protein made by that gene The deletion shown above results in cystic fibrosis. Deletions, cont’d If one or two nucleotides is deleted (or anything that is not a multiple of three), the deletion can change the amino acids for everything past the deletion Insertions Insertion – adding one or more nucleotides If a set of three nucleotides is added, then the protein will have an additional amino acid Insertions, cont’d If one or two nucleotides is added (or anything that is not a multiple of three), the insertion can change the amino acids for everything past the insertion Frameshift Mutations Frameshift mutations: any changes that add or subtract nucleotides causing a change in the sequence of every codon after the mutation. This affects the “reading frame” – AAT/CGG/ACC – if “T” is inserted after the first “C”, it will now read AAT/CTG/GAC/C… changing all of the amino acids after the insertion Frameshift Mutations Results when one or two nucleotides / bases are inserted or deleted (or any number of bases that is not a multiple of 3) Causes of Mutations bacteria / viruses environmental / chemical Video clip – 1:06 UV radiation Various pollutants genetic Some types of cancer (which is caused by a mutation in the DNA of the cells that become cancerous) can have a genetic predisposition – making it more likely someone will get that type of cancer