Date of publication: 2017-07-09 13:13
Scientists have also discovered that viral intruders have driven the evolution of human physiological functions ranging from early development to digestion.
66. The rate of photosynthesis may vary with changes that occur in environmental temperature, wavelength of light, and light intensity. Using a photosynthetic organism of your choice, choose only ONE of the three variables (temperature, wavelength of light, or light intensity) and for this variable
58. Discuss how cellular structures, including the plasma membrane, specialized endoplasmic reticulum, cytoskeletal elements, and mitochondria, function together in the contraction of skeletal muscle cells.
76. Survival depends on the ability of an organism to respond to changes in its environment. Some plants flower in response to changes in day length. Some mammals may run or fight when frightened. For both of these examples, describe the physiological mechanisms involved in the response.
In order to better understand the evolution of the DNA replication apparatus, it would be necessary to determine with some confidence when and where the independent inventions of the bacterial and the eukaryal/archaeal versions of nonorthologous DNA replication mechanisms occurred (either before or after LUCA, either in cells or in viruses?). We will discuss now several specific points of the above hypotheses (except hypothesis 6 that we have ruled out) in an attempt to answer some of these questions.
Hi Rendy, Feel free to use the text anyway you like. The photos, however, belong to the people listed in the photo captions. You need to get their permission before using them.
The hypothesis 8 implies that the two distinct sets of DNA replication proteins originated after LUCA, one in a proto-bacterium and one in a common lineage to Archaea and Eukarya ( fig. 6 ). This is in nice agreement with the classical rooting of the universal tree of life in the bacterial branch. However, this rooting is highly disputed. 66 , 67 It has been shown that phylogenetic data that support this rooting are not valid (which does not mean that this rooting is wrong) and other hypotheses have been proposed, such as an eukaryal rooting, 65 or a fusion between a proto-bacterium and a proto-archaeon to give Eukarya. 68
NIGMS Program Director Dan Janes replies: 8775 Absolutely. Identifying location and timing of retroviral and transposon integration into host genomes is a vigorous field of contemporary research. For example, Mouse Mammary Tumor Virus (MMTV) appears to integrate uniformly across host genomes [including 8775 junk DNA 8776 ] whereas integration of other retroviruses is influenced by functional and structural features such as chromatin compaction and replication timing. 8776
55. Beginning at the presynaptic membrane of the neuromuscular junction, describe the physical and biochemical events involved in the contraction of a skeletal muscle fiber. Include the structure of the fiber in your discussion.
58. Describe the effects of plant hormones on plant growth and development. Design an experiment to demonstrate the effect of one of these plant hormones on plant growth and development.
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I was tempted by the amylase data. It seems possible that the pancreas may be involved as carbohydrate metabolism kregulated in part by pancreas. Any thoughts?
79. Describe how the following adaptations have increased the evolutionary success of the organisms that possess them. Include in your discussion the structure and function related to each adaptation.