Question

Pstl is a restriction enzyme produced by the bacterium Providencia stuartii. It recognizes the six base pair sequence 5-CTGCAG-3. Why is the chromosome of P. stuartii not degraded by Psti? CAR P. stuarti DNA is unmethylated within the recognition sequence for Pstl, and is not degraded by Pstl, which only digests methylated DNA B. It is not understood why the P. stuartii genome is not degraded by Psti. C. P. stuarti DNA is methylated within the recognition sequence for Pstl, and is not degraded by Pstl, which only digests non-methylated DNA The DNA sequence 5'-CTGCAG-3' is not found in P. stuartii. E The chromosome of P. stuartiiis digested by Pstl, but P. stuartii has specialized repair mechanisms which quickly splice the digested DNA back together. QUESTION 6 Which direction(s) will kinesin and dynein transport vesicles in the axon of the neuron shown below? Cell Body Axon Synapse A Dynein will move vesicles inward (toward the cell body) and kinesin will move vesicles outward (toward the synapse). B. Both dynein and kinesin will move vesicles inward toward the cell body). Dynein will move vesicles outward (toward the synapse) and kinesin will move vesicles inward (toward the cell body). D. It is not possible to predict the direction of vesicle transport. . Both dynein and kinesin will move vesicles outward (toward the synapso).

Answer 1

1) Correct answer is C. Before coming to the explanation let me first discuss about RM system which is called restriction modification system. In this system the bacteria adds methy group( CH3 ) group to it's native DNA by methytransferase enzyme and protects it's own DNA from cutting down by restriction enzymes because the restriction enzymes have to ability to work on DNA which is not methylated and this PstI works on non-methylated DNA.

2) Correct answer is A. Both kinesin and dynein are motor proteins that act as cargo carriers in neurons and helps in axonal transport. Kinesin do a anterograde movement by taking cargo/vesicles from Soma to axon tip and dynein do a retrograde movement by taking cargo/vesicles towards Soma(cell body).