DNAase is an enzyme that catalyzes the hydrolysis of the covalent bonds that join nucleotides together. What would first happen to DNA molecules treated with DNAase?
A) The purines would be separated from the deoxyribose sugars.
B) The pyrimidines would be separated from the deoxyribose sugars.
C) All bases would be separated from the deoxyribose sugars.
D) The two strands of the double helix would separate.
E) The phosphodiester bonds between deoxyribose sugars would be broken.
Answer:
E) The phosphodiester bonds between deoxyribose sugars would be broken.
Explanation:
The purines and pyrimidines of two DNA strands of a DNA duplex are held together by hydrogen bonds. Hydrogen bonds are not covalent bonds. The enzyme DNAase targets the phosphodiester bonds. These are the covalent bonds that join two deoxyribonucleotides of a DNA strand together. therefore, when a DNA is subjected to digestion with DNAase enzyme, the phosphodiester bonds will be broken that hold the pentose sugars of two nucleotides by a phosphate group.
Polymorphic. Polymorphisms
refer to spasmodic genetic variation within the same species of an organism resulting in varying forms of the species. Polymorphic viruses, mutate at faster rates hence the virus
population is subject to high rates of turnovers. The high divergence of various
species, such as influenza, is as a result of 0.01 mutations per nucleotide site
per year.
Answer:
Dust bowl resulted from extreme drying and loosening of the soil that resulted in soil erosion by wind. Thus, it can be related that poor agricultural practices like over plowing , over grazing and leaving the land barren are human activities that must have contributed to the dust bowl.
Explanation:
- Dust bowl is referred to a period in early twentieth century when the the American and Canadian prairies faced severe dust storms.
- These dust storms resulted from severe drought and failure of practices to prevent soil erosion.
- Several people and livestock died as a result of choking.
- Over plowing, removal of top soil and small grasses exposed the soil to eroding winds and caused the dust storms.
Answer:
The correct answer is D sister chromatids;centromere
Explanation:
After DNA replication during s phase or synthesis phase of interphase of the cell cycle,each chromosome has a copy and the cell that is newly formed is now 4n.
We cal these identical pairs sister chromatids and they are held together by a centromere
