After transcription, mRNA may undergo significant editing. Compare and contrast RNA editing in prokaryotes and eukaryotes and connect how these differences affect genome size and gene content
What will be an ideal response?
Answer: RNA editing occurs after transcription of mRNA. Introns are pieces of RNA that are removed after transcription and before translation. Eukaryotic mRNA undergoes extensive RNA editing after transcription and in general eukaryotic genes contain many more introns than do prokaryotic genes. The number of introns per gene in eukaryotic genes ranges from 0-10, while most prokaryotic genes do not have any. The number of introns per gene is positively correlated with genome size. As the number of introns per gene increases, the genome size increases. The number of ORFs per 1000 nucleotides thus tends to decrease. In general, prokaryotic genomes encode for more genes (ORFs) per every 1000 base due to the lack of introns and less regulatory DNA.
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Mycobacterium tuberculosis has chemicals in its cell wall that inhibit the fusion of phagocytic vacuoles with lysosomes. Which statement is true?
A. Antibodies produced by the cells can more effectively kill the bacteria. B. The bacterium can survive and replicate inside of the phagocytic cell. C. The bacterium can produce chemicals which can destroy the macrophage housing the bacterium. D. Complement proteins will take over to destroy the bacteria.
Early successional species are characterized by
A) low body growth rates. B) smaller body size. C) low degree of dispersal. D) low per capita population growth rate.
Which of the following is an accurate description of Mendel's Law of Segregation?
a) Individuals possess two copies of every gene in their somatic cells. b) Individuals can have different versions (alleles) of a gene in their somatic cells. c) When gametes are formed, there is only one copy of every gene in each gamete. d) Different pairs of homologous chromosomes will line up at the metaphase I plate independently from each other.
Contractile vacuoles
A) are generally found in protists that inhabit salt water. B) help in the excretion of excess salt. C) prevent cells from bursting as a result of the influx of excess water. D) allow organisms to avoid dehydration by absorbing water from the environment.