30) Protein Synthesis and Critical Thinking Questions 4 & 5

DNA serves as the matter blueprint for protein synthesis. DNA specifies only that structure of protein molecules, including the enzymes that catalyze the synthesis of all classes of biological molecules. Most metabolic machinery of the cell is concerned in some way with protein synthesis. Two types of protein synthesis include transcription and translation.
-Transcription: involves the transfer of information from a DNA gene's base sequence to the complementary base sequence of an mRNA (messenger RNA) molecule. Once the mRNA molecule is made, it detaches and leaves the nucleus via a nuclear pore. Only DNA and mRNA are involved in the transcription process.
-Translation: the language of nucleic acids is translated into the language of proteins. The process of translation occurs in the cytoplasm and involves all varieties of RNA: tRNA (transfer RNA), rRNA (ribosomal RNA) and mRNA (messenger RNA). When translation reaches the cytoplasm, the mRNA molecule carries the instructions for the particular protein to a small ribosomal unit by bas pairing to rRNA. Then tRNA begins to transfer amino acids, dissolved in the cytosol, to the ribosome. There are approximately 20 different types of tRNA, each capable of binding with a specific amino acid. The attachment process is controlled by a synthetase enzyme and is activated by ATP. Once its amino acid is loaded, the tRNA migrates to the ribosome, where it maneuvers the amino acid into the proper position, as specified by the mRNA codons.

4) G1 and S are specific phases of DNA replication. Damaged chromosomes and damaged DNA will be prevented from leaving the G1 phase and moving to the S, if that specific tumor-suppressor gene is working propertly. If not damaged chromosomes and DNA will be placed into new daughter cells and cause a malfunction within the body. Another tumor-suppressor gene will prevent damaged chromosomes and damaged DNA from passing from G2 to M, which are also phases of DNA replication. If this particular tumor-suppressor gene fails to work, damaged chromosomes and DNA will end up in the new daughter cells and also cause a malfunction within the body. Cancer may be the result of one or more specific tumor-suppressor genes fail to function properly.

5) Peroxisomes are responsible for the breakdown of toxins. Peroxisomes are membranous sacs containing a variety of powerful enzymes such as oxidases and catalases. Oxidases use molecular oxygen to detoxify harmful substances like the chemical preservatives phenol, formaldehyde and alcohol, which the students were exposed too.