Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
From DNA to Protein (11.2) What is a Protein? • Complex, 3-dimensional structures made from chains of amino acids • Regulate cell functions • Produced at the ribosomes • Ex: Blood contains red blood cells (RBC) that transport oxygen to different parts of our bodies. • RBC’s use a protein called “hemoglobin” to capture and carry the oxygen. • If the instructions (DNA) are changed or “mutated” changes in the hemoglobin protein could result. The RBCwould no longer be able to carry oxygen (Sickle Cell Anemia). Sickle Cell Anemia How are proteins made? Protein Synthesis • RNA (Ribose Nucleic Acid) How does RNA differ from DNA? ▫ Single stranded (half-zipper) ▫ The sugar in RNA is ribose (DNA has deoxyribose) ▫ Instead of Thymine (T), RNA contains Uracil (U) in RNA Adenine (A) pairs with Uracil (U) 3 types of RNA • Messenger RNA (mRNA) -Brings instructions from DNA in the nucleus to the cytoplasm • Ribosomal RNA (rRNA) -binds to the mRNA and uses instructions to assemble the amino acids in the correct order • Transfer RNA (tRNA) -Supplier. Delivers amino acids to the ribosome to be assembled into a protein. (amino acid delivery truck) Transcription (DNA mRNA) • Enzyme unzips DNA molecule • Free RNA nucleotides form with complementary base pair (GC and AU) • New mRNA strand leaves nucleus and enters the cytoplasm (finds ribosome) • http://www.stolaf.edu/people/giannini/flashani mat/molgenetics/transcription.swf DNA replication vs. Transcription • Double stranded DNA ▫ Purpose? • Single stranded RNA ▫ Purpose? Genetic Code • 3 nitrogenous bases of mRNA code for one Amino Acid • Each group is known as a codon • Ex: The codon GCU results in the amino acid Alanine • 64 combinations are possible when using a sequence of 3 nitrogenous bases • Universal Code for all organisms Genetic Code “Alphabet” Proteins Chains of amino acids Amino Acids (Serine, Leucine, etc) Codons (3 nucleotides -UCA, CUA, etc) Nucleotide Nitrogenous Base Translation (mRNA protein) p.294 • Occurs in the cytoplasm at the ribosomes • mRNA attaches to ribosome. tRNA (carrying a specific AA) approaches ribosome • tRNA (anticodon) attaches with mRNA (codon) • A new tRNA molecule attaches next to previous tRNA molecule and AA from each tRNA bond together (peptide bond) • Ribosome slides down mRNA molecule to allow a new tRNA to attach. Old tRNA molecules are released. • A long chain of AA is formedprotein!! Protein Synthesis Animation Do it yourself