1. How does DNA encode information? DNA is a double-stranded helix composed of a phosphate backbone and deoxyribose, and encodes information by the sequence of its nucleotide bases, which are composed of adenine, thiamine, guanine and cytosine. DNA undergoes transcription, which produces single-stranded mRNA, which uses uracil in place of thiamine. Next step is translation, in which the RNA becomes a protein, which then can act as structural units or enzymes. 2. How does DNA replicate itself? In order to replicate itself, DNA undergoes DNA replication, a process in which the DNA unwinds and splits in two. From that point on, new nucleotides are added to each of the original strands (A to T, C to G) until the result is two identical sequence copies of DNA. 3. How is DNA information used to synthesize polypeptides? A gene or protein is used to make polypeptides. In order to create this gene, transcription and translation must take place to create a protein from DNA. In transcription, DNA polymerase unwinds DNA and makes the …show more content…
Are all genes expressed in all cells? No they are not, even though all cells have the same genetic code. Certain genes are not expressed in cells and are turned "off". The different pattern of expressed genes in different cells allow the cells to perform specific activities needed for those cells to do for an organism. 5. How do the processes of meiosis and fertilization produce genetic variety? During the meiosis stage of crossing over, the maternal and paternal homologous chromosome segments are being exchanged. During independent assortment, different genes independently separate from one another. During random fertilization, no gamete has a greater chance than the other with fusing together in sperm and zygote fusion. These processes contribute to the production of genetic variety because of the many opportunities of unique combinations, unlike the process of mitosis, in which identical daughter cells are always the