Suppose that the following DNA molecule replicates to produce twodaughter molecu

Question

Suppose that the following DNA molecule replicates to produce twodaughter molecules. Write out the nucleotide sequence of thesedaughter molecules by using black for previously polymerized andred for newly polymerized.

(I understand the sequencing A with T C with G, but I don'tunderstand how you determine which is newly polymerized and why onestarts with the 3' end versus the 5' end, can anyone explainthis?

TTGG.....TAAT
AACC.....ATTA

5'TTGG...TAAT3'
3'AACC...ATTA5'  
and
5'TTGG....TAAT3'
3'AACC.....ATTA5'

Also, if I assumed that the original bottom strand was thetemplate, how would I write an RNA transcript?

Thank you, I'll give you lifesaver points!

Explanation / Answer

      Replication is a mechanismof duplication of DNA where new DNA is synthesized by taking theinformation from the        parentalstrand.             The enzymes thatsynthesize DNA are known as DNA dependent DNA polymerases orsimply DNApolymerases.       These DNA polymerasessynthesize DNA only in 5' to 3'direction but not in 3'to 5' direction.       So for this reason theparental strand that is 3'-5' direction synthesizes its daughterstrand continuously without any       breaks while the strandthat is 5'-3' direction cannot be synthesized continuously.       This strand is synthesizeddiscontinuously in the form of fragments known as Okazaki fragments.       For the synthesis of thisstrand, the parental strand forms a loop and within the loop thedirection of the strand changes       due to which DNApolymerases synthesize the looped fragment.       Once the loop has beensynthesized, it gets unwound and the next segment undergoeslooping.       In this process the entirestrand gets synthesized and finally all the fragments gets joinedby the enzyme called DNA       Ligase.       5'T T G G...T A AT3'____________parental strand
      3'A ACC... AT T A5' ____________newly synthesized daughterstand.                     3'A A C C.....A T TA5'__________parental strand       5'TT G G.... T A AT3'___________newly synthesized daughterstrand.
      For the synthesis of RNA theDNA strand that is in 3'-5' direction acts as template.       The enzyme thatsynthesizes RNA is known as RNA polymerase.       In RNA synthesis, the baseUracil is presentinstead of Thymineso, where ever there is Adenine in the DNA strand in       the RNA it is occupied byUracil instead of Thymine.       So the sequence ofnucleotides in RNA for the DNA strand that is in 3'-5' directionwill be as:       3'A A C C.....A T TA5'__________template DNA strand       5'UU G G.....U A AU3'__________newly synthesized RNAstrand(RNA transcript)
      Hope you are satisfied with theanswer.

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