IB Biology - Unit 7 - Nucleic Acids HL 100% Solved

IB Biology - Unit 7 - Nucleic Acids HL 100% Solved Antiparallel strands DNA is anti-parellel, meaning the strands run in opposite directions to each other. If one has a 3' at the top the other has a 3' at the bottom, Purines Adenine and Guanine. Pyrimidines Cytosine, Thymine and Uracil Nucleosomes Used for packing DNA, made up of a length of DNA around a group of 8 histones Supercoiling of DNA Winding of DNA strands, this can reduce the size of DNA by 10000x, using nucleosomes. Introns RNA splicing extracts these, which are sequences that do not contribute to the formation of polypeptides. The remaining coding areas of the mRNA are called exons Okazaki fragments Sections formed as a result of discontinuous synthesis by DNA polymerase on the lagging strand RNA nucleotide Contains one ribose sugar, phosphate group and a base they are the complementary nucleotides of the anti-sense nucleotide bases Sense strand The complementary of the anti-sense strand in transcription it is the coding strand Promoter gene (transcription) Allows the binding of RNA polymerase which is then able to find the anti-sense strand, start the transcription. DNA Translation Process by which mRNA is converted into a protein Initiation A-site, first codon is introduced to the ribosome, tRNA comes in with an anti- codon which has an induced fit and begins the translation Elongation P-site, peptidal bonding site makes a peptide bond through enzymes between the two amino acids made at the A-site Termination E-site, mRNA and ribosome detach and the polypeptide is released and the tRNA returns to join with more amino acids Start codons and stop codons Codons