Answer the following question given this paragraph: Air temperature in the stratosphere layer increases with altitude. Why? The stratosphere gets most of its heat from the Sun. Therefore, it's warmer closer to the Sun. The air at the bottom of the stratosphere is cold. The cold air is dense, so it doesn't rise. As a result, there is little mixing of air in this layer. Q: Where does the stratosphere get most of its heat? Choices: - time - earth - volcanoes - sun A:
sun
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Answer the following question given this paragraph: Motion of water molecules helps break up interactions between solid ions or molecules. Q: Motion of water molecules helps break up interactions between what? Choices: - ions or hormones - acids and bases - enzymes and acids - solid ions or molecules A:
solid ions or molecules
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Answer the following question given this paragraph: disease is sex-linked and effects mainly males (who are XY, compared to XX females).273 In the unaffected population, the FMR-1 gene contains between 6 to 50 copies of a CGG repeat. Individuals with between 6 to 50 repeats are phenotypically normal. Those with 50 to 200 repeats carry what is known as a pre-mutation; these individuals rarely display symptoms but can transmit the disease to their children. Those with more than 200 repeats typically display symptoms and often have what appears to be a broken X chromosome from which the disease derives its name. The pathogenic sequence in Fragile X is downstream of the FMR1 gene's coding region. When this region expands, it inhibits the gene's activity. 274 Other DNA Defects: Defects in DNA repair can lead to severe diseases and often a susceptibility to cancer. A OMIM search for DNA repair returns 654 entries! For example, defects in mismatch repair lead to a susceptibility to colon cancer, while defects in translation-coupled DNA repair are associated with Cockayne syndrome. People with Cockayne's syndrome are sensitive to light, short and appear to age prematurely.275 Summary: Our introduction to genes has necessarily been quite foundational. There are lots of variations and associated complexities that occur within the biological world. The key ideas are that genes represent biologically meaningful DNA sequences. To be meaningful, the sequence must play a role within the organism, typically by encoding a gene product (which we will consider next) and/or the information needed to insure its correct "expression", that is, where and when the information in the gene is used. A practical problem is that most studies of genes are carried out using organisms grown in the lab or in otherwise artificial or unnatural conditions. It might be possible for an organism to exist with an amorphic mutation in a gene in the lab, whereas organisms that carry that allele may well be at a significant reproductive disadvantage in the real world. Moreover, a particular set of... Q: What is the term for biologically meaningful dna sequences? Choices: - atoms - eggs - babies - genes A:
genes
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Answer the following question given this paragraph: The Chromosome 18 Inversion Not all structural rearrangements of chromosomes produce nonviable, impaired, or infertile individuals. In rare instances, such a change can result in the evolution of a new species. In fact, a pericentric inversion in chromosome 18 appears to have contributed to the evolution of humans. This inversion is not present in our closest genetic relatives, the chimpanzees. Humans and chimpanzees differ cytogenetically by pericentric inversions on several chromosomes and by the fusion of two separate chromosomes in chimpanzees that correspond to chromosome two in humans. The pericentric chromosome 18 inversion is believed to have occurred in early humans following their divergence from a common ancestor with chimpanzees approximately five million years ago. Researchers characterizing this inversion have suggested that approximately 19,000 nucleotide bases were duplicated on 18p, and the duplicated region inverted and reinserted on chromosome 18 of an ancestral human. A comparison of human and chimpanzee genes in the region of this inversion indicates that two genesROCK1 and USP14that are adjacent on chimpanzee chromosome 17 (which corresponds to human chromosome 18) are more distantly positioned on human chromosome 18. This suggests that one of the inversion breakpoints occurred between these two genes. Interestingly, humans and chimpanzees express USP14 at distinct levels in specific cell types, including cortical cells and fibroblasts. Perhaps the chromosome 18 inversion in an ancestral human repositioned specific genes and reset their expression levels in a useful way. Because both ROCK1 and USP14 encode cellular enzymes, a change in their expression could alter cellular function. It is not known how this inversion contributed to hominid evolution, [1] but it appears to be a significant factor in the divergence of humans from other primates. Translocations A translocation occurs when a segment of a chromosome dissociates and reattaches to a different, nonhomologous chromosome.... Q: Not all structural rearrangements of chromosomes produce nonviable, impaired, or infertile individuals. in rare instances, such a change can result in the evolution of what? Choices: - new order - new mutation - new family - new species A:
new species
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