DNA Unit


Essential Skills

            1.  Be able to explain the 2 reasons why DNA is important in organisms.

            2.  Be able to explain the structure of DNA, including the following terms: Nucleotide, Double Helix, complementary bases.

            3.  Be able to explain the difference between Transcription and Translation in terms of location in the cell, why they occur, and the nucleic acids (DNA, mRNA, rRNA, tRNA) involved.

            4.  Be able to use the Genetic Code to identify codons, anti-codons and amino acids from a DNA sequence.



            Nucleotides                  mRNA                         anticodon                     polypeptide

            Deoxyribose                 rRNA                           introns                          start codon

            Ribose                          tRNA                           exons                           stop codon

            Phosphate                    ribosome                      DNA replication           genetic code

            Nitrogen base               complimentry DNA      transcription                  mutation

            Amino acids                 template DNA              translation                     insertion

            Peptide bonds              codon                           protein synthesis           deletion

            Tay-Sachs                    Sickle-cell anemia         gene expression           

            Carboxyly group           amino group                 R-group          


Homework Questions

  1. What is the main reason for DNA replication in cells?
  2. What is the main reason for Protein synthesis (transcription and translation) in the cell?
  3. Where is DNA located in the cell?
  4. What is the shape of DNA?
  5. What is the monomer for DNA?
  6. What are the 3 parts of a nucleotide?
  7. What 2 molecules make up the “uprights” of the DNA ladder?
  8. What make up the rungs of the DNA ladder?
  9. Why must a purine always bond with a pyrimidine?
  10. What nitrogen base must always bond with Adenine? Cytocine?

12.  Use the DNA diagram to complete the following questions.

      a. Circle one nucleotide.

b. Fill in the complimentary bases on the right strand of  DNA.

c. What shape does DNA form? 


  1.  How does DNA Replicate?  Describe the process.
  2. What do the enzymes DNA polymerase and Helicase do in the process of DNA replication?
  3. Why is DNA replication called “Semiconservative”?
  4. Write the complimentry bases for the following strand of DNA

                  A   T   C   T   A   T   G   C   A   T   G   A   C

17. What does DNA code for?

18.  Describe the process of transcription.  What is the purpose of RNA polymerase?

19.  Where does transcription occur?

20.  What molecule begins transcription, what molecule is made at the end of transcription?

21.  Describe the process of translation.  Where does translation occur in the cell?

22.  What is the purpose or rRNA, tRNA?

23.  Define codon and anticodon.  Where are each found?

24.  What molecule is used in the beginning of translation, what molecule is made at the end of translation?

25.  What is the genetic code?  Why is it said to be universal?

26.  Who are Watson, Crick and Rosalind Franklin?

      27.  What are the 3’ and 5’ ends of DNA. What does the term “antiparallel” mean?                         

      28.  List 3 structural differences between DNA and RNA.

  1.  Complete the following table

Template DNA












Amino Acid