Chapter 16-17 Remediation (Kayla Ruiz)

Chapter 16-17 Quest Remediation

Missed Concepts and Terms:

• The translation of mRNA into polypeptides
• Regarding this topic, I misnomered the two steps of translation and the specificity between its components. First, aminoacyl-tRNA synthetase must match tRNA and an amino acid, then there must be a correct match between the tRNA anticodon and an mRNA codon. It does not truly matter whether the ribosome is specific to either of the mRNA or tRNA components; ribosomes only facilitate their coupling. 

• The structure and process of tRNA
• I forgot what happened at the jutting 3' end of the tRNA molecule. This is the site where amino acids attach during translation.

• Types of mutations
• While the term "point mutation" generally applies to any mutation that alters a single base pair, a missense mutation is the right name for the given mutation in the quest. The codon would still code for an amino acid, just not the correct amino acid. 

• Difference between eukaryotic and prokaryotic codons
• In this question, I probably confused the difference between eukaryotic and prokaryotic codons for the differences in the bases of RNA and DNA. The genetic code is nearly universal because it is used by the simplest bacteria and the most complex animal species. There are differences between codons, but the proteins to which they correspond are the same in all organisms. The language of codons is seen as "glowing" genes of jellyfish are transferred to other organisms.

• Addition of amino acids to the polypeptide chain
• With this, I forgot the three steps in the addition of an amino acid to the growing chain in tRNA. There is codon recognition with the tRNA in the A site, then a peptide bond forms between it and the tRNA in the P site. Finally, there is translocation: the tRNA is "kicked out" of the P site into the E site.
• In a different but related question, I should have identified the A site as the site where the codon is being read in the ribosome.

• What causes termination of transcription
• I forgot the difference between termination of transcription in prokaryotes and eukaryotes. In the former, the polymerase stops transcription at the end of the terminator and the mRNA can be translated without further modification. In eukaryotes, RNA polymerase II transcribes the polyadenylation sequence.

• Semi-conservative process
• Watson and Crick's semiconservative model states that when a double helix replicates, each daughter molecule will have one old strand from the parent and one newly made strand. This was examined in an experiment in which older strands were marked with a heavy isotope, newer strands with a light isotope, and bands of replicated DNA were examined. If DNA were replicated in a conservative manner, the older DNA strands would rejoin. It would be seen as two separate bands of DNA. 

• The purpose of telomerase
• This enzyme catalyzes the lengthening of telomeres in germ cells. It does not necessarily cause their shortening, however.

• The purpose of DNA polymerase
• This enzyme catalyzes the elongation of new DNA at the replication fork. It adds nucleotides only to the free 3' end of the growing strand so a new DNA strand can only elongate in the 5' to 3' direction.

• The purpose of telomeres
• A telomere is defined as the nucleotide sequences at the end of DNA molecules that postpone the erosion of genes.