DNA Replication Review Helicase unzips double helix Hydrogen
DNA Replication - Review � Helicase unzips double helix. � Hydrogen bonds between nitrogen bases are broken. � DNA Polymerase brings in new nucleotides using the parent strand as a template. A matches with T � C matches with G � � Every 3 nucleotides codes for an amino acid. � Amino acids Protein
Protein Synthesis
Protein Synthesis: The Big Picture
RNA REVIEW RNA (ribonucleic acid) � Single-stranded (not double-stranded) � Contains ribose sugar (not deoxyribose) � Contains Uracil (instead of Thymine)
RNA REVIEW 3 Types of RNA: 1. m. RNA (messenger RNA) Ø Complementary copy of DNA. Ø Moves from nucleus to ribosome. Ø Codon: 3 nitrogenous bases (codes for an amino acid) 2. t. RNA (transfer RNA) Ø Transfers amino acid to ribosome. Ø Contains amino acid & anti-codon: 3 bases (complement to m. RNA codon) 3. r. RNA (ribosomal RNA) Ø Makes up the ribosome.
Ribosome: � Protein factory � Contains 2 subunits. � Made of r. RNA and protein.
Transcription: m. RNA makes a copy of a DNA segment. � Location: Nucleus � RNA polymerase adds nucleotides. � *Don’t forget: U is used instead of T � Example DNA: ACG � TCA TTC GCA m. RNA UGC AGU AAG CGU
Translation: m. RNA is used as a template to create proteins. � m. RNA travels from the nucleus to the cytoplasm. � The two ribosome subunits clamp onto the m. RNA. � t. RNA brings an amino acid to the ribosome. � t. RNA’s anticodon bonds to its complementary m. RNA codon (this is called base pairing). � Amino acids are attached together with peptide bonds to form proteins (polypeptides).
Translation � 64 possible m. RNA codons: � Different codons can code for the same amino acid � There are only 20 amino acids. � Others code for instructions: � START codon: AUG (also codes for methionine) � STOP codon: UAA (does not code for an amino acid)
Common Origin of Life � ALL organisms use the same genetic code Evidence that all life evolved from a common origin.
Translation Example – Make a Protein! m. RNA strand: AUG CCC CUU AAA GAG UUU ACA UAU UGC UGG AGG CGU UAA Protein: Start/ Met- Pro- Leu- Lys- Glu- Phe- Thr- Tyr- Cys- Typ- Arg- Stop
Translation Practice 1. m. RNA: AUGCUUUUAGCACGACAACAAUGUUGA Protein: 2. m. RNA: AUGUAUCAAGAUGAUACAGUUUUUUAG Protein: 3. DNA: TACGGTCATCGTGCA m. RNA: Protein: 4. DNA: TACGGCAATATT m. RNA: Protein:
- Slides: 12