Tutor profile: Catherine S.
Subject: Environmental Science
Describe how humans are altering the biosphere.
Humans are increasing the rate of extinction by over-harvesting, degrading, and destroying habitats which is causing endangered species, threatened species, and endemic species. Humans activities can also threaten entire ecosystems, as when poor agricultural practices cause desertification or deforestation, which destroys forest. Pollutants such as those that cause acid rain threaten rainforest ecosystems. Biological magnification occurs when a pollutant is passed along a food chain. trash that gets into fresh water can make its way into oceans, where it degrades marine ecosystems. Ozone is a pollutant near the ground, but ozone layer is a global threat caused by use of chemicals called CFCs. Global climate change caused by rising concentration of greenhouse gases also threatens the biosphere. Biodiversity includes the diversity of genes, species, and ecosystems. All three levels of biodiversity are declining. A decrease in biodiversity can harm humans. We rely on ecosystems to produce oxygen and decompose waste. We also benefit from many compounds produced by wild species, and by tapping their genetic diversity to enhance our crops.
Describe the process of protein synthesis.
A gene is a DNA sequence that encodes an RNA or protein product. Converting the information encoded by a gene into its product starts with RNA synthesis (transcription), during which enzymes use the gene's DNA sequence as a template to assemble a strand of RNA. DNA is inside the nucleus and has four nucleotide bases ATCG and RNA is transcribed. Transcirption is the process by which enzymes assemble an RNA using the nucleotide sequence of a gene as a template. mRNA, which is a type of RNA that has a protein building message. Then a message is translated into tRNA, which is a type of RNA that delivers amino acid to a ribosome during translation. Translation is a process by which a polypeptide chain is assembled from amino acids in the order specified by an mRNA.
Electrolytes serve four general functions in the body. Describe what those functions are.
Electrolytes serve four general functions in the body which include the ability to control the osmosis of water between body compartments; help maintain the acid-base balance required for normal cellular activities; electrolytes carry electrical current, which allows production of action potentials and graded potentials and controls secretion of some hormones and neurotransmitters; several ions are co-factors needed for optimal activity of enzymes.
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