Answer:
Transcription and translation occur simultaneously in prokaryotes.
Explanation:
Prokaryotes lack membrane-bound organelles and therefore, do not have a nucleus. Transcription and translation occur in the cytoplasm. As soon as the required length of mRNA is being formed, ribosomes join it and start the process of translation. Prokaryotic genes lack introns. The primary transcript formed by transcription in prokaryotes does not undergo splicing.
On the other hand, the process of transcription occurs in the nucleus in eukaryotes while translation occurs in the cytoplasm. The primary transcript formed by transcription in eukaryotes undergoes modifications to remove introns and to add a poly-A tail and 5' cap. Post-transcriptional modifications and spatial separation of two processes in eukaryotes result in slower translation than prokaryotes.
Prokaryotic cells because they don't have a nuclei.
Answer: The greenhouse gas emissions from the extraction of bitumen and the use of large quantities of water.
Explanation:
Bitumen is a natural flammable organic matter formed from kerogen in the process of petroleum generation, which is soluble in carbon disulfide. Asphalt and mineral wax are examples of hydrocarbons which are part of bitumen. Conventional oil is extracted by wells while <u>oil sands deposits are extracted using surface mining sectioning techniques, or are flowed to wells by in situ techniques that reduce bitumen viscosity by steam and/or solvents.</u> So, unlike crude oil extracted in oil wells, bitumen requires an open-pit mining operation, in which large tracts are washed with a mixture of water and chemicals to separate the bitumen from a mixture of sand and clay.
Two consequences of this practice are:
- The greenhouse gas emissions from the extraction of bitumen are larger than the extraction of conventional oil. The emissions produced contribute to enhance the greenhouse effect and cause global warming. The greenhouse effect occurs when certain gases retain part of the energy emitted by the earth's soil when heated by the sun's radiation. This phenomenon occurs naturally, and thanks to it, the average temperature of the Earth is about 14º C (57.2 °F). The problem occurs when these greenhouse gases increase in the atmosphere and the amount of energy that is not released into space also increases and, with it, the Earth's temperature.
- The extraction of bitumen from oil sands requires the use of large quantities of water, and even though water used here can be recycled, only a small amounts is returned to the natural cycle. Also, spills from the transportation of the oil could damage soils and waterways, increasing water pollution. This toxic water could get into surface.
It's either the tradeoffs between conservation and economic development or the potential benefit to farmers.
