Question

5. You extract chromosomal DNA from 5 cultures of bacteria given to you by another researcher. You are trying to determine if any of the cultures are related to each other, or if they are different. You perform a restriction digest with a restriction enzyme AluI and run the resulting digested DNA out on a 1% agarose gel. The banding patterns in lanes 1 and 5 look the same, but the banding patterns in lanes 2, 3, and 4 look different from the rest. What can you conclude from this information?

6. Suppose you want multiple copies of a gene you have synthesized. How would you obtain the necessary copies by cloning? By PCR?

7. Why did the use of DNA polymerase from the bacterium Thermus aquaticus allow researchers to add the necessary reagents to tubes in a preprogrammed heating block?

8. Explain the difference between antigenic shift and antigenic drift. Using the example of influenza, why is there such concern about the possible emergence of a particularly virulent strain of influenza?

Answer 1

Answer 5) that means chromosomal dna at 1 and 5 are of same size and at lane 2,3,4 are of same size.

Answer 6) Yes, by performing PCR we can get multiple copies of required DNA.

Answer 7) Thermus aquaticus has proven to be quite a useful organism in the field of Biotechnology, as its enzyme Taq polymerase is harvested for use in polymerase chain reactions (PCR). The reason Taq polymerase is used in PCR, as opposed to other forms of the polymerase enzyme is because Thermus aquaticus' form of the enzyme is well-suited for the repetitive heating involved in PCR and will not denature. Taq polymerase's resistance to heat is an adaptation to its environment, but is not the only reason it is the choice for use in PCR. Taq polymerase is also chosen because it is incredibly accurate, at 1x10^-4 to 2x10^-5 errors per base pair, and does not need to be completely pure to be effective. These properties of Taq polymerase- it's heat resistance, accuracy, and potency- make PCR, and technologies that utilize PCR, such as DNA fingerprinting, enzyme production, and medical diagnoses possible.

Answer 8)

S.N.	Antigenic Shift	Antigenic Drift
1	Major Antigenic Change	Minor Antigenic Change
2	Forming new sub-type (Subtype A + Subtype B –> New Subtype)	Forming new strain of virus
3	One or Two Viruses are Involved	Only one virus is involve
4	Occurs once in a time	Occurs frequently
5	May jump from one species to another (animal-human)	May infect animals of the same species
6	Large change in nucleotides of RNA	Small mutation of RNA
7	Occurs as a results of genome reassortment between difference subtypes.	Occurs as a result of the accumulation of point mutations in the gene.
8	An antigenic change which results in drastic or dramatic alternation in HA (hemagglutinin) or NA (neuraminidase) subtypes.	An antigenic change can alter antigenic sites on the molecule such that a virion can escape recognition by the host’s immune system.
9	Large and sudden mutation	Random and Spontaneous Mutation
10	Difficult to treat (need new vaccine)	Easy to treat (antibody and drugs available)
11	Occurs only in Influenza Virus A	Occurs in Influenza Virus A, B and C
12	Give rise to pandemics, which occurs irregularly and unpredictably.	Usually responsible for epidemics in between pandemics.
13	Example: The 1968 pandemic arose when the H3 hemagglutinin gene and one other internal gene from an avian donor reassorted with the N2 neuraminidase and five other genes from the H2N2 human strain that had been in circulation. Example: The 1918 pandemic arose when an avian H1N1 strain mutated to enable its rapid and efficient transfer from human-to-human.	Example: The subtle mutations accumulated through antigenic drift of these subtypes (e.g., H1N1, H3N2, H5N1) give rise to different strains of each subtype. Example: Antigenic drift is also known to occur in HIV (human immunodeficiency virus), which causes AIDS, and in certain rhinoviruses, which cause common colds in humans. It also has been suspected to occur in some cancer-causing viruses in humans