Transcript How does DNA control cell activities?
How does DNA control cell activities? Protein Production • The sequence of nucleotides in DNA contains instructions for producing proteins. • What are proteins? • Which cellular organelles are associated with the production of proteins? What are proteins? • Polymers constructed from long chains of amino acids. – Peptide bonds join together amino acids. • Proteins regulate cell functions. • Comprise filaments in muscle tissue • Enzymes control chemical reactions in a cell – Breaking down glucose – Forming spindle fibers in mitosis How many types of nucleic acids are found in your cells? • DNA – Deoxyribonucleic Acid – 5-Carbon Sugar = Deoxyribose – Double-stranded • RNA – Ribonucleic Acid – 5-Carbon Sugar = Ribose – Single-stranded RNA-What does it do? • Same nitrogenous bases as DNA…EXCEPT thymine is replaced with URACIL • Uracil pairs with Adenine • Takes instructions from DNA and builds proteins amino acid by amino acid. How many types of RNA help build proteins? • mRNA – Messenger RNA – Copies instructions from DNA in nucleus – Brings instructions from nucleus to the cytoplasm to the ribosome – CODON • Three nucleotide sequence that codes for a specific amino acid How many types of RNA help build proteins? • rRNA – Ribosomal RNA – Composes ribosomes – Binds to mRNA and uses instructions to assemble amino acids in the correct order How many types of RNA help build proteins? • tRNA – Transfer RNA – Delivers amino acids to ribosome for protein assembly – ANTICODON • Three-nucleotide sequence attached to amino acid. • Complimentary to mRNA codon Process of protein synthesis • http://www.lewport.wnyric.org/JWANAMA KER/animations/Protein%20Synthesis%20 -%20long.html Two Parts of Protein Synthesis • TRANSCRIPTION – Occurs in nucleus – mRNA gets information from DNA and takes out to ribosomes • TRANSLATION – Occurs at ribosomes in cytoplasm – Converts information in mRNA sequence into a sequence of amino acids in a protein Transcription Process • Enzymes unzip DNA molecule in specific location • Free RNA nucleotides form complimentary base • • pairs with the nucleotides on the DNA strand mRNA strand breaks away and DNA strand rejoins mRNA strand leaves the nucleus and enters the cytoplasm through nuclear pores Translation Process • For protein assembly, different amino acids in cytoplasm must be delivered to the ribosomes • Each tRNA molecule attaches to a specific amino acid • tRNA ANTICODONS pair with complimentary mRNA CODON Translation Process • Amino acids form peptide bonds with each other to form long chains called POLYPEPTIDES or PROTEINS • This process continues until a STOP codon is reached Translation Process • Then the amino acid chain breaks off and twists into a complex 3D shape • Different proteins = Different cell structures and enzymes