Nucleic Acids. One-letter abbreviation. 1.1* Base / Nucleotide DNA / RNA / Both. 1.2* Base / Nucleotide DNA / RNA / Both

Transcription

1 Chime 11 Name: Chapter 22 (please print) Nucleic Acids Read and answer each question carefully and thoroughly. Please do not crowd your answers. Use scratch paper to work out each problem and write the final answer on this worksheet. Those parts of an exercise which have on-screen answers are identified by an asterisk; e.g., 1.1*. You should do these problems first, check your answers at the bottom of the web page, and then do the rest. 1. There are 5 heterocyclic nitrogen-containing bases in nucleic acids. These compounds are derived from either purine or pyrimidine, the parent compounds. Name the following bases using the complete name and the one-letter abbreviation. Decide what is the parent compound for each of the models. Model Complete Name One-letter abbreviation Parent Compound 1.1* Use the models to complete the statements. a. Identify each as either a base or nucleotide. b. State whether each is present in DNA, RNA, or both. Model a. Base or Nucleotide? (circle one) b. Present in: (circle one) 1.1* Base / Nucleotide DNA / RNA / Both 1.2* Base / Nucleotide DNA / RNA / Both 1.3 Base / Nucleotide DNA / RNA / Both 1.4 Base / Nucleotide DNA / RNA / Both 1.5 Base / Nucleotide DNA / RNA / Both 1.6 Base / Nucleotide DNA / RNA / Both

2 3. a. Name the bases(s) that will hydrogen bond with each of the following bases. b. Draw the structures of the base pairs and show the hydrogen bonding. c. How many hydrogen bonds exist for each base pair? 3.1* a. Bases that this compound will hydrogen bond with: 3.2 a. Bases that this compound will hydrogen bond with: 3.3 a. Bases that this compound will hydrogen bond with: 3.4 a. Bases that this compound will hydrogen bond with:

3 4. The following sets of double-stranded DNA each undergo replication. a. Write out the sequences of the two new segments of double-stranded DNA. b. Label the daughter strands and the parent strands. c. Show which daughter strand will be formed from Okazaki fragments. Set 1* Set 2 5. Draw the structures of the following models. a. Label the oxygen atom(s) which normally bond to a phosphate in a nucleic acid. b. Label the carbon atoms which normally bond to a base in a nucleic acid. c. Give the names of the heterocyclic rings. d. Decide what configuration each model exists as, alpha or beta. e. Number the carbon atoms. f. Describe the difference between these two models. 5.1* a, b & e. Structure with labels and numbered carbon atoms: 5.2 a, b & e. Structure with labels and numbered carbon atoms: c. Name of heterocyclic ring: d. Configuration: alpha / beta c. Name of heterocyclic ring: d. Configuration: alpha / beta f. Difference between models:

4 6. a. Name the following compounds: b. Draw the nucleic acid backbone which is formed from these compounds. Show at least 3 repeating units. c. Label the 5' end and the 3' end. d. What type of reaction occurs to covalently bond the repeating units together? 7a. What is the name of the repeating unit found in this segment of nucleic acid? b. Draw and name the sugar involved in this model. Number the sugar carbons. Name: c. How many phosphate groups are in this piece of nucleic acid? How many sugar groups? d. Name the nucleotide at the 5' end and the 3' end, respectively. 5 end 3 end

5 e. List the bases present in this fragment. f. What does 3'-5' phosphodiester linkage mean? g. Using the standard code write out the base sequence from the 5 end to the 3 end of the DNA segment. h. How many total hydrogen bonds would exist between these two strands? i. Using the standard code write out sequence of the mrna transcription from this nucleic acid segment. j. Using the mrna sequence write out the sequence of anti-codons found on the trna s. k. Name the small model above. In what kind of nucleic acid is this compound found?

6 8. Given the following peptides, a. Write out the sequence of codons in the mrna. b. Label the 5' and 3' ends. Set 1* Set 2 c. Write out the anticodons in the trna that correspond to each peptide. Set 1* Set 2 d. There is more than one correct mrna sequence for each peptide, why?