Nucleic Acids

• DNA are involved in the storage and transfer of genetic information
• DNA are passed from existing cell to new cells during cell division
• RNA are directly involved in the synthesis of proteins
• Nearly all DNA is found within the cell nucleus
• RNA occurs in all parts of the cell
• Any given nucleotide in a nucleic acid contains one pentose sugar, one heterocyclic base, and one phosphate group
• For the incorporation into a nucleotide, there are 2 sugars and 5 heterocyclic bases available
• There are 2 different heterocyclic bases that are purine derivatives available for incorporation of nucleotide: Adenine and Guanine
• There are 3 different heterocyclic bases that are pyrimidine derivatives available for incorporation of nucleotide: Thymine, Cytosine, Uracil
• What is the name of the pentose sugar present?

  Ribose

  
• Is the heterocyclic base present a purine or a pyramidine?

  Purine

  
• What is the name of the heterocyclic base present?

  Adenine

  
• Would this nucleotide be found in DNA and RNA molecules?

  RNA

  
• The phosphate group is only present in nucleotide and not in nucleoside
• The phosphate subunit is bonded to the sugar subunit
• The sugar subunit is bonded to the base subunit
• The nucleotide AMP is found in RNA molecules but not in DNA molecules
• The primary structure of a nucleic acid is determined by the sequence of bases present
• The "backbone" of a nucleic acid molecule involves an alternating sequence of sugar and phosphate groups
• In a segment of a nucleic acid each nonterminal phosphate group carries a 1- charge
• In a segment of a nucleic acid a terminal phosphate group is found at the 5' end of the segment
• The sequence of bases in a segment of nucleic acid is always read in the 5' to 3' direction
• Predict the sequence of bases in the DNA strand that is complementary to the single DNA strand shown:

  5' C-G-A-A-T-C-C-T-A 3'

  3' G-C-T-T-A-G-G-A-T 5'
• Hydrogen bonds help hold the two nucleotide strands together
• Complementary base pairing occurs within the double helix
• What is the complementary base for C in DNA molecules?

  G
• Fifteen percent of the bases in a certain DNA molecule are found to be T. What percent of the bases in the same molecule are G?

  35%
• What is the correct complementary DNA sequence for the DNA base sequence 5' C-G-A-A-T 3' ?

  3' G-C-T-T-A 5'
• Replication of DNA produces two daughter molecules in which each daughter molecule contains one parent strand and one newly synthesized strand
• In DNA replication the DNA double helix unwinds under the influence of DNA helicase
• In DNA replication the new strand that is synthesized in small segments is called the lagging strand
• A chromosome is a protein-DNA complex that contains a single DNA molecule
• The first phase of protein synthesis is called transcription
• The product of the first phase of protein synthesis is RNA molecules
• RNA molecules differ from DNA molecules in that they are single stranded rather than double stranded
• The m in the designation mRNA stands for messenger
• The t in the designation of tRNA stands for transfer
• What type of RNA is involved in the transcription phase of protein synthesis ?

  hnRNA
• From the base sequence 5' A-T-G-C-C-A 3' in a DNA template strand, determine the base sequence in the hnRNA synthesized from the DNA template strand

  3' U-A-C-G-G-U 5'
• The transcription phase of protein synthesis is where a partial unwinding of the DNA double helix occurs