Strand a 5 atcgatccctag 3 strand b 3 tagctagggatc 5

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Strand A: 5’-ATCGATCCCTAG-3’ Strand B: 3’-TAGCTAGGGATC-5’ DNA strands run parallel to each other in opposite directions, so one strand is oriented in the 5’ to 3’ direction, while the other strand is oriented in the 3’ to 5’ direction. yes Because new nucleotides are only added to the free 3’ hydroxyl end of a chain of nucleotides, replication can only take place in the 5’ to 3’ direction. Therefore Strand B (lagging strand) is where Okazaki fragments would be formed and Strand A is the leading strand due to it’s 5’ to 3’ orientation. yes 37. Summarize the key events in eukaryotic protein synthesis using the following key terms: transcription, DNA, RNA polymerase, introns, exons, mRNA, translation, codons, tRNA, rRNA, ribosomes, post-transcriptional modification, spliceosomes, promoter sequence, amino acids, and proteins. The process of eukaryotic protein synthesis starts with transcription in the nucleus. Yes Protein synthesis is initiated when the RNA polymerase attaches to a promoter sequence Yes on the template strand of DNA. It starts creating mRNA by transcribing the gene small segments at a time. Working in small segments protects the exposed DNA from being destroyed by enzymes in the nucleus that can cause damage. A transcription bubble trails after the RNA polymerase as it moves in a 3’ to 5’ direction down the DNA template strand. Yes The transcribed mRNA is made up of the available RNA nucleotides in the nucleus. The 3’ end of the mRNA is where the nucleotides get added. The RNA polymerase matches the DNA’s nucleotides with the complementary RNA nucleotide. The mRNA nucleotides are connected by the phosphodiester bonds of the preceding nucleotide’s 5-phosphate and 3-hydroxyl group. Yes Once the RNA polymerase is ordered to ‘STOP’ at the last part of the gene by a certain combination of DNA nucleotides, no more RNA nucleotides are added to the mRNA. The RNA polymerase gets disengaged from the template strand by a GC hairpin, a U-shaped combo of guanine and cytosine. The RNA polymerase and mRNA detach. The mRNA proceeds to the cytoplasm for translation while the RNA polymerase detaches from the template strand and can repeat the transcription process again. Yes The mature mRNA is stabilized before leaving the nucleus and gains the ability to resist degradation from destructive enzymes in the cytoplasm with the addition of a 3’ poly-A tail and a 5’ methylguanine cap. Yes Then, spliceosomes remove the introns that do not translate into proteins
and splice together the exons, the coding DNA, creating a consolidated strand of coding mRNA, an mRNA transcript. The mRNA transcript is now ready to enter the nucleus and undergo translation. Yes The conversion of amino acids into protein is built upon the trio of nucleotide bases that form a codon during the translation stage. Yes When a mRNA’s start codon and a ribosome connect, translation begins. Meanwhile, different amino acids attach to different tRNAs, with the help of ATP, depending on the tRNAs arrangement of anticodons, another trio of nucleotides. The amino acid-

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