GENETICS PROTEIN SYNTHESIS DNA VS RNA Structure DNA

GENETICS

PROTEIN SYNTHESIS

DNA VS. RNA Structure DNA Structure Single stranded Double stranded Sugar = ribose Sugar = deoxyribose Bases: Adenine Cytosine Guanine Uracil Thymine

RNA FUNCTION-MAKE PROTEINS! Messenger RNA (m. RNA) Carries DNA message from nucleus to ribosome Ribosomal RNA (r. RNA) Makes up part of the ribosome Transfer RNA (t. RNA) Carries the correct amino acid to the ribosome

TRANSCRIPTION & TRANSLATION Two steps: Transcription: Process of copying a DNA message onto an m. RNA molecule. Translation: Process of translating the message on an m. RNA into a protein.

TRANSCRIPTION the production of an m. RNA copy of a gene for use in protein synthesis this process allows the cell to keep the DNA master copy safe within the nucleus uses RNA polymerase to match up bases to make a copy of one gene that will code for a protein when complete, the m. RNA copy detaches, leaves the nucleus, and attaches to a ribosome in the cytoplasm

TRANSLATION the process of turning the code contained in DNA into a sequence of amino acids – occurs at ribosomes every 3 bases on the m. RNA equals one codon each codon codes for a specific amino acid each codon on the m. RNA matches up to an anticodon on a t. RNA (which carries the correct amino acid) this translation of the codons in m. RNA into a sequence of amino acids is how proteins are made, and how genes are expressed

CENTRAL DOGMA 1. DNA 2. Transcription 3. m. RNA 4. Translation 5. Protein

DETAILED STEPS: TRANSCRIPTION 1. the DNA unwinds at the gene that needs to be copied 2. RNA polymerase matches up RNA nucleotides to the exposed gene sequence on the DNA 3. As RNA polymerase matches the nucleotides, they join together to form a strand of m. RNA 4. Once the gene is copied, the m. RNA disconnects from the DNA and is edited before leaving the nucleus.

DETAILED STEPS: TRANSLATION 1. the m. RNA binds to a ribosome at the start codon (AUG) 2. the t. RNA with the correct anti-codon (UAC) and the amino acid Methionine (Met) joins to the start codon 3. the t. RNA with the correct anticodon binds to the next codon 4. a peptide bond forms between Methionine and the amino acid attached to the second t. RNA 5. as each t. RNA binds to the m. RNA, the amino acids are joined into a peptide chain 6. when complete, the peptide chain is modified and folded to become a functional protein 7. each t. RNA reloads with the correct amino acid to be ready for the round of protein synthesis

CODONS & ANTI-CODONS every 3 nucleotides makes up a codon, and each codon matches up with an anti-codon on a t. RNA molecule that has a specific amino acid attached to the other end

PROTEIN SYNTHESIS Example: DNA: TAC CGG TAA CGC m. RNA: AUG GCC AUU GCG Met Ile Ala Amino Acid: Ala