Question

DNA Replication Assignment

Answer 1

Answer:

The correct answer will be:

Case I:

Original DNA:                                 ATG AAC CAT TCA GTA TGG

Complimentary DNA:                     TAC TTG GCA AGT CAT ACC

Transcript mRNA molecule:          AUG AAC CGU UCA GUA UGG

Translated sequence:                    Met- Asn - Arg - Ser - Val-  Trp

Case II:

Original DNA:                                   ATG  GGT   CTA  GCG  AAA  GAT

Complimentary DNA:                     TAC  CCA  GAT  CGC  TTT   CTA

Transcript mRNA molecule:           AUG  GGU CUA  GCG  AAA  GAU

Translated sequence:                     Met  -Gly-    Leu-   Ala-  Lys -   Asp

Explanation:

DNA replication is a process which produces a replica or exact copy of the DNA molecule by using one strand of the existing DNA as a template. The new strand is formed using Chargaff rule which states that purine binds pyrimidine that is adenine(A) will bind to thymine (T) and guanine (G) will bind to cytosine (C).

Transcription is a process which produces an mRNA molecule from one strand of DNA molecule. The mRNA acts as a messenger molecule which is formed with the same Chargaff rule except for a different nitrogenous base  "uracil". In mRNA uracil (U) will bind complementarily to adenine (A) instead of thymine.

The translation is a process which synthesizes the protein by reading the bases of mRNA in the triplets called 'codons". These codons code for a specific amino acid which bond to each other via peptide bond and form protein.

Answer 2

Answer:

1st template:

Original DNA:               ATG AAC CAT TCA GTA TGG

Complimentary DNA:   TAC TTG GCA AGT CAT ACC

mRNA molecule:          AUG AAC CGU UCA GUA UGG

AMINO ACID:               Methionine (Start) - Aspargine (Asn) - Arginine (Arg) - Serine (Ser)- Valine (Val) - Tryprophan (STOP)

2nd template:

Original DNA:               ATG  GGT   CTA  GCG  AAA  GAT

Complimentary DNA:   TAC  CCA  GAT  CGC  TTT   CTA

mRNA molecule:          AUG  GGU CUA  GCG  AAA  GAU

AMINO ACID:               Methionine (Start) - Glycine (Gly) - Leucine (Leu) - Alanine (Ala) - Lysine (Lys) - Apspartic Acid (Asp)

Explanation:

When you are forming the DNA complimentary strand you need to remember that they come in base pairs, and each base pairs up with a specific base. In the case of DNA the base pairs are the following:

A - T ; T - A

C - G; G - C

So:

For every A, its complimentary is T. For every T, it's complimentary is A.

For every C, it's complimentary is G. For every G, it's complimentary is C.

So in the case of your 1st DNA template:

Original DNA:                ATG AAC CAT TCA GTA TGG

Complimentary DNA:   TAC TTG GCA AGT CAT ACC

During transcription however, mRNA is formed. RNA does not have thymine (T), but Uracil (U) instead. So the base pairs would be different in the case of Adenine(A), thymine and Uracil.

A - U; T - A

C - G; G -C

So:

For every A, it's complimentary is U. For every T, it's complimentary is A.

For every C, it's complimentary is G. For every G, it's complimentary is C.

Going back to your 1st DNA template:

Original DNA:               ATG AAC CAT TCA GTA TGG

Complimentary DNA:   TAC TTG GCA AGT CAT ACC

mRNA molecule:          AUG AAC CGU UCA GUA UGG

Duing translation, tRNA brings the amino acids to the mRNA strand. There is a specific RNA codon sequence that codes for a specific AMINO ACID. These codons are 3 bases grouped together. You can use the table attached to see the amino acid each combination.

Amino acids are the building blocks of protein. The DNA templates determines the type of protein that will be made. The tRNA brings the amino acid to the mRNA template. Then it drops the amino acid off, which will bond with the next amino acid coded to attach to it.

So if you take the first mRNA codon AUG, you can see in the table that it codes for Methionine, which is a start codon, meaning this is the start of a new protein. It will then attach to the next amino acid that codes for the next codon which is AAC that codes for Aspargin. They will continue until it reaches a STOP codon, which means it would be the end of that protein.

Again going back to the template:

mRNA               AUG AAC CGU UCA GUA UGG

AMINOACID:    Methionine (Start) - Aspargine (Asn) - Arginine (Arg) - Serine (Ser)- Valine (Val) - Tryprophan (STOP)

I hope this will help you to some degree.