Activity Overview


During this investigation you will complete three activities.

  1. In the first activity, you will learn about the methods involved in the replication of deoxyribonucleic acid (DNA) by using polymerase chain reaction (PCR). Then you will review the technique, cycle sequencing, used to determine the nucleotide sequences in a strand of DNA.
  2. In Activity 2, you will submit two nucleotide sequences to a database for analysis. Based on the results, you will make conclusions regarding the source of the DNA.
  3. Finally, in Activity 3, you will show the relationship between DNA, RNA and protein. The assignment will be to first determine the complementary sequence of a mRNA strand that corresponds to a portion of a DNA strand. Then, you will decode the mRNA into the primary structure of the protein (sequence of amino acids).


Activity One

Activity 2
Activity 3

Amino Acid: An organic molecule possessing both carboxyl and amino groups. Amino acids serve as the monomers of proteins.
Complementary: The two strands of DNA are said to be complementary to each other; that is, the sequences of bases on one strand determines the sequences of bases on the other. For example adenine pairs with thymine and guanine pairs with cytosine. Likewise, mRNA is also complementary to DNA. However, uracil replaces thymine in DNA. The DNA sequence ATTCGA would be copied by mRNA UAAGCU.

Deoxyribonucleic Acid (DNA): A double-stranded, helical nucleic acid molecule capable of replicating and determining the inherited structure of a cell's proteins.


Cycle Sequencing: A method used for determining the nucleotide sequence of DNA molecules. It involves synthesizing in vitro DNA strands complementary to one of the strands of DNA being sequenced. The method is based on the random incorporation of a modified nucleotide. A series of DNA fragments is synthesized that reflects all the positions of the modified nucleotides, and thus ultimately the sequence of the DNA.


Messenger RNA (mRNA): A type of RNA synthesized from DNA in the genetic material that attaches to ribosomes in the cytoplasm and specifies the primary structure of a protein.


Nucleotide: Structural unit of a nucleic acid (subunit of RNA or DNA) consisting of three parts: a sugar, a phospate group, and a base (DNA: ATCG or RNA: AUCG).


Polymerase Chain Reaction (PCR): A technique for amplifying DNA in vitro by incubating with special primers, DNA polymerase molecules and nucleotides.


Primary Structure: The level of protein structure referring to the specific sequence of amino acids.


Protein: A three-dimensional biological polymer constructed from a set of 20 different monomers called amino acids.


Ribonucleic Acid (RNA): A single-stranded nucleic acid molecule involved in protein synthesis, the structure of which is specified by DNA.


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