Bacteria and fungi carry out decompostion of plants and animals
Answer: d). UAG
Explanation: During translation, DNA sequence is first of all copied into an mRNA in a process known as transcription. This is the first step in protein synthesis. The mRNA is used as a template in protein synthesis. The genetic information encoded in an mRNA are in form of codons. A Codon is a three nucleotide sequence that codes for a specific amino acid. These codons are recognized by anticodons in a tRNA molecule. An anticodon is a three-base sequence on the tRNA through which tRNA base pair with mRNA.
From the DNA sequence above, 3'TAG will first be transcribed into an mRNA sequence AUC, then the anticodon on the tRNA will be UAG. The mRNA codon-tRNA anticodon base pairing follows the Watson and Crick base pairing in which Adenine pairs with Uracil and Cytosine pairs with Guanine.
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.
