Why isn't bacterial DNA digested by the restriction enzymes bacteria produce?
A) The sequence recognized and cleaved by a restriction enzyme is not found in the bacterial genome.
B) Bacterial cells have high concentrations of ligase which immediately repairs the any sites that are cleaved.
C) Methyl groups added to the bases of restriction enzyme recognition sites within the bacterial chromosome block cleavage.
D) Bacterial DNA is modified with phosphate groups that prevent the function of restriction enzymes.
E) Restriction enzymes are found in the cytoplasm and DNA is only in the nucleus.
C) Methyl groups added to the bases of restriction enzyme recognition sites within the bacterial chromosome block cleavage.
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Inbred lines of animals, such as laboratory mice, are useful for studying complex traits because:
A. individuals are genetically identical, so differences in traits must be due to environmental differences. B. although individuals differ both genetically and environmentally, the genetic differences are known, so differences in traits can be understood. C. animals are kept in identical environments, so any differences in traits are due to differences in their genes. D. both genetic and environmental differences between individuals are known, making differences in their traits easy to understand. E. None of these choices is correct.
The internal urethral sphincter is composed of smooth muscle, and the external urethral sphincter is composed of skeletal muscle; together, they control the process of urination
Indicate whether the statement is true or false
When a segment of DNA duplicates, causing two copies of a gene to be present in the chromosome, the duplicate copy could possibly (Check all that apply)
A. gain a new function due to mutation. B. become a centromere. C. become a pseudogene. D. lose function due to mutation. E. become an ortholog.
Which apicomplexan has caused outbreaks, associated with fecal-contaminated imported raspberries, and also fresh greens and drinking water?
A. Toxoplasmosis B. Babesiosis C. Cryptosporidiosis D. Cyclosporiasis E. None of the choices are correct.