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devlian [24]
3 years ago
7

Iron is part of the hemoglobin in red blood cells. what is the purpose of hemoglobin?

Biology
1 answer:
m_a_m_a [10]3 years ago
4 0
The main purpose of hemoglobin is the transport of OXYGEN and CARBON DIOXIDE
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This planet is an extremely light colored blue, and is the 7th planet from the Sun.
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Uranus is the seventh planet from the sun and the first to be discovered by scientists. Uranus is blue-green in color, the result of methane in its mostly hydrogen-helium atmosphere.
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A plant leaf is constructed from a variety of cell types with specialized structures and functions. Many of the properties of le
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<span>The apoplast and symplast are two locales of the plant that fill in as pathways for water and solute transport over both short and long separations. These pathways are spoken to by the bolts in the graph beneath, which indicates three adjoining cells in a leaf or root.</span>
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3 years ago
A molecule that can be used as a molecular clock has a neutral mutation rate of one mutation per 5 million years. How many years
gregori [183]

Answer:To put dates on events in evolutionary history, biologists count how many mutations have accumulated over time in a species’ genes. But these “molecular clocks” can be fickle. A paper in the 28 September Physical Review Letters mathematically relates erratic “ticking” of the clock to properties of the DNA sequence. Researchers may eventually use the results to select which genes make the best clocks.

Although mutations in DNA are rare, they are crucial for evolution. Each mutation in a gene changes one small piece of a protein molecule’s structure–sometimes rendering it non-functional and occasionally improving it. The vast majority of mutations, however, neither hurt nor help, often because they affect an unimportant part of their protein. Such a “neutral” mutation usually dies out over the generations, but occasionally one proliferates until virtually every individual has it, permanently “fixing” the mutation in the evolving species.

Over thousands of generations, these fixed mutations accumulate. To gauge the time since two species diverged from a common ancestor, biologists count the number of differences between stretches of their DNA. But different DNA segments (genes) often give different answers, and those answers differ by much more than would be expected if the average rate of mutations remained constant over evolutionary time. Sometimes they also disagree with dates inferred from fossils. Now Alpan Raval, of the Keck Graduate Institute and Claremont Graduate University, both in Claremont, California, has put precise mathematical limits on this variation.

Raval’s work is based on representing possible DNA sequences for a gene as a network of interconnected points or “nodes.” Each point represents a version of the gene sequence that differs by exactly one neutral mutation–a single DNA “letter”–from its immediate neighbors. The network contains only neutral mutations; non-functional versions of the sequence aren’t part of the network.

Models and simulations had suggested that if the number of neighbors varies from point to point–that is, if some sequences allow more neutral mutations than others–mutations accumulate erratically over time, making the molecular clock unreliable. Raval calculates precise limits on how unsteady the clock could get, based on properties of the network, such as the average number of neighbors for each node or the number of “jumps” connecting any two randomly chosen nodes. “The great strength of this paper is that it’s now mathematically worked out in much more detail than before,” says Erik van Nimwegen of the University of Basel and the Swiss Institute of Bioinformatics in Switzerland, who developed the framework that Raval uses.

Still, the relevant network properties are “not very intuitive,” van Nimwegen observes. Raval agrees. “The real question from this point on would be to identify what kinds of proteins would be good molecular clocks.” He says that according to his results, for a protein to be a good clock, “virtually all single mutations [should] be neutral”–many neighbors per node–but “as you start accumulating double and triple mutants, it should quickly become dysfunctional.” Raval is working to relate these network features to protein properties that researchers could measure in the lab.

Researchers have suggested other explanations for the erratic behavior of molecular clocks, such as variations in the mutation rate because of changes in the environment. But such environmental changes are relatively fast, so their effect should average out over evolutionary time, says David Cutler of Emory University in Atlanta. He says that in network models, by contrast, changes in the mutation rate are naturally slow because the point representing the current sequence moves slowly around the network as mutations accumulate.

Explanation:

4 0
2 years ago
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A client in the intensive care unit who has a brain tumor has experienced a sharp decline. The care team suspects that water and
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Answer:

The correct answer is vasogenic edema.

Explanation:

A kind of cerebral edema in which the blood-brain barrier is disrupted is termed as vasogenic cerebral edema. It refers to extracellular edema that primarily influences the white matter through leakage of fluid from the capillaries.  

It is primarily witnessed surrounding the brain tumors, that is, both primary and secondary and the cerebral abscesses, however, some of the vasogenic edema may be witnessed around the developing cerebral hemorrhage and cerebral contusion.  

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3 years ago
Scientists discovered fossils in several layers of the Earth you see here. They found fossils of algae, snails, and clams in lay
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The answer is C. F

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3 years ago
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