What is the argument that, although human mitochondria all descend from a single ancestral population, this may not be true for nuclear genomes?
What will be an ideal response?
By comparing the genomes of organelles with those of proteobacteria, there is a strong degree of conservation between the genes of mitochondria and of proteobacteria. Human-like mitochondria can be traced to a time before the evident evolution of humans. Thus, mitochondria from one human to the next have not diverged. Over time, the nuclear genomes of organisms retained their own informational genes, and many endosymbiont operational genes were transferred to the nuclear genome and often replaced their functional equivalents. Unlike the cases of the mitochondria and chloroplasts, where the endosymbionts can be traced to specific lineages of Bacteria, the putative ancestor for the human nuclear genome may have come from several lineages after the endosymbiosis event.
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A mutation that reduces the efficacy of arginase 1 will result in a buildup of what molecule?
a. urea b. arginosuccinate c. l-arginine d. ornithine
What adaptation allows sea snakes to remain submerged for long periods of time? a. Able to absorb carbon dioxide through the skin
b. They breathe air. c. Dual lungs that extend almost to the tail. d. Able to lower metabolic rate.
If the frequency of a recessive gene in a population in genetic equilibrium is 40 percent, in the next generation, the frequency of that gene would be ____.
A. 20 percent B. 40 percent C. 80 percent D. 2pq E. unpredictable
Bacteria have a region of the cytoplasm known as the ________, which is not bounded by a membrane but contains the chromosome.
Fill in the blank(s) with the appropriate word(s).