Question

i need help in biochem

1. Which of the following statements is true?
   1. Exonuclease III cleaves DNA in a sequence specific manner
   2. Bacteriophage lambda exonuclease adds homopolymer tails to the 3’ –OH ends of a linear duplex
   3. Alkaline phosphatase removes terminal phosphates
   4. Kinase removes nucleotides from 5‘ends

2. (5 points) Arrange the following steps involved in Gene cloning in the correct order

a) Expression of recombinant gene in host

b) Insertion of isolated gene to the vector

c) Extraction of recombinant gene product

d) Isolation of desired gene

e) Introduction of recombinant vector to the host

1. Explain how enzymes work and what effect they have on activation energy and free energy of a chemical reaction. Why do scientists use buffered solutions to carry out enzymatic reactions?

Answer 1

• Among the options the correct one is alkaline phosphatase removes terminal phosphates.

It removes 5' phosphate groups from DNA and RNA. It will also remove phosphates from nucleotides and proteins.

• Enzymes form complexes with their substrates. The binding of a substrate to an enzyme active site is termed the "enzyme-substrate complex". It lowers the activation energy for a particular reaction and increases the rate of reaction

Enzyme lowers free energy of activation, but it has no effect on the free energy of reaction.

• Enzyme is very much sensitive to pH. Even enzymes can be denatured in low pH. So always scientists use buffer solution to carry out enzyme mediated reaction to maintain a more or less constant pH medium.