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I. What is the correct order of enzyme action during DNA replication? Number the

ID: 279725 • Letter: I

Question

I. What is the correct order of enzyme action during DNA replication? Number the steps from 1 to 7. Synthesis of RNA primers (priming) Helicase/topoisomerase activity DNA polymerization/proofreading 5'-3'exonuclease activity/DNA polymerization Ligation Single-stranded binding proteins bind and preventreannealing Binding to origin of replication (AT rich sequence) II. Using the genetic code table below, please answer the following questions: SECOND LETTER UAU UAC UAA (terminator) UAG Amber CAU CAC UCU UGU UGC UGA Opal UGG Trp Phe Tyr UCA UCG CCu terminator Leu (terminator) CUU CUC CUA CUG AUU AUC lleu AUA AUG Met CGU cGCArg CGA CGG AGU AGC AGA AGG IS Leu CCA CCG ACU ACC ACA CAG Ser AAC Lys (initiator) ACG GCU GCC GCA GUG (initiator) GCG AAG GAU GAC Asp G?GUA GUC Val GGC Glu GAG

Explanation / Answer

I.             Correct order of enzyme action during DNA replication

Numbering from step 1 to 7 are as follows:

Step 1: binding to origin of replication

Step 2 : helicase / topoisomerase activity

Step 3 : single strand binding proteins bind and prevent reannealing.

Step 4 : synthesis of RNA primer

Step 5: DNA polymerization

Step 6 : 5’-3’ exonuclease activity

Step 7 : ligation

   II.

a) given DNA – 3’ TACATAACCATT 5’

when transcribed– 5’ AUGUAUUGGUAA 3’

When translated : Met-Tyr-Trp (UAA is a stop codon so, translation terminates)

Ribonucleic acid is nucleic acid with 5’ to 3’ ends ( 5’ AUGUAUUGGUAA 3’ )

       b)    Using the DNA sequence above , new DNA sequence from 3’ to 5’ that incorporates silent mutation is :

               3’ TACATGACCATT 5’

Silent mutation means change a codon to the synonyms codon that specifies the same amino acid altering DNA sequence without changing the amino acid sequence of protein ( here the protein sequence remains same Met-Tyr-Trp)

   c) Using the DNA sequence above , new DNA sequence from 3’ to 5’ that incorporates nonsense mutation is :

                                                  3’ TACATAACTATT 5’

                       Nonsense mutation means changes from sense codon into a nonsense codon (stop codon)

d) Using the DNA sequence above , new DNA sequence from 3’ to 5’ that incorporates missense mutation in   second amino acid is :

3’ TACTTAACCATT 5’

Misense mutation means a base substitution that results in different amino acid in protein( here , after missense mutation the amino acid sequence will be Met-Asn-Trp )

Numbering from step 1 to 7 are as follows:

Step 1: binding to origin of replication

Step 2 : helicase / topoisomerase activity

Step 3 : single strand binding proteins bind and prevent reannealing.

Step 4 : synthesis of RNA primer

Step 5: DNA polymerization

Step 6 : 5’-3’ exonuclease activity

Step 7 : ligation

when transcribed– 5’ AUGUAUUGGUAA 3’

When translated : Met-Tyr-Trp (UAA is a stop codon so, translation terminates)

Ribonucleic acid is nucleic acid with 5’ to 3’ ends ( 5’ AUGUAUUGGUAA 3’ )

3’ TACATGACCATT 5’

Silent mutation means change a codon to the synonyms codon that specifies the same amino acid altering DNA sequence without changing the amino acid sequence of protein ( here the protein sequence remains sameMet-Tyr-Trp)

                                                           3’ TACATAACTATT 5’

                       Nonsense mutation means changes from sense codon into a nonsense codon (stop   codon)

3’ TACTTAACCATT 5’

Misense mutation means a base substitution that results in different amino acid in protein( here , after missense mutation the amino acid sequence will be Met-Asn-Trp )

Numbering from step 1 to 7 are as follows:

Step 1: binding to origin of replication

Step 2 : helicase / topoisomerase activity

Step 3 : single strand binding proteins bind and prevent reannealing.

Step 4 : synthesis of RNA primer

Step 5: DNA polymerization

Step 6 : 5’-3’ exonuclease activity

Step 7 : ligation

when transcribed– 5’ AUGUAUUGGUAA 3’

When translated : Met-Tyr-Trp (UAA is a stop codon so, translation terminates)

Ribonucleic acid is nucleic acid with 5’ to 3’ ends ( 5’ AUGUAUUGGUAA 3’ )

3’ TACATGACCATT 5’

Silent mutation means change a codon to the synonyms codon that specifies the same amino acid altering DNA sequence without changing the amino acid sequence of protein ( here the protein sequence remains sameMet-Tyr-Trp)

                                                           3’ TACATAACTATT 5’

                       Nonsense mutation means changes from sense codon into a nonsense codon (stop   codon)

3’ TACTTAACCATT 5’

Misense mutation means a base substitution that results in different amino acid in protein( here , after missense mutation the amino acid sequence will be Met-Asn-Trp )