Question

1. Write an equation for the DNA replication reaction. List all the reactants and all the products. (The equation does not need to be perfectly balanced.) 2. This diagram shows the process of DNA replication. Label the primers and DNA polymerases, and add two arrows to show the direction of movement of the DNA polymerases. Circle an area where helicase would be located. 3. A segment of a template DNA strand has the sequence shown below. Add the appropriate nucleotides to show the result of the action of DNA polymerase, but assume that the polymerase makes one mistake that results in a base mismatch. Circle the mismatched base pair. 3'-CGTG ATC G G - 5' 4. * Assume that the mismatched DNA in your answer to Question 3 is not repaired. When this DNA is replicated again, will one, both, or neither of the resulting two DNA molecules contain a mismatch? is replication again,willone, bolih, or néither of the resulting two

Answer 1

Question 1

Existing strand + deoxynucleotide triphosphate ———> Elongated strand + pyrophosphate

Reactants: Existing strand or parent DNA and deoxynucleotides

Products: Elongated new daughter strand and pyrophosphate

Question 2

1

a- primers (Initiators of DNA synthesis)

b- leading (top) and lagging (bottom) strand (Newly synthesised strand)

c- DNA polymerase III(synthesis of new nucleotide bases)

d- Helicase (unwind the DNA strand to make replucation fork)

Question 3

3’ C G T G A T C G G 5’

5’ G C A C C A G C C 3’

Polymerase add nucleotides in replication rule: DNA- Guanine (G) always pair with the Cytosine (C) and Adenine (A) always pair with the Thymine (T).

(In the above given strand bold C is mismatch pair).

Question 4

One of the resulting strand is affected due to mismatch.

Because, only one strand has mismatched, so when this replicates, one correct DNA  sequence and one mismatched sequence will form.