1.1 Structure and Roles of Nucleic Acids

• What is the process of translation?

  the decoding of an mRNA message into a protein
• What is the process of transcription?

  the process of RNA copying DNA to make codons
• what are the two stages of protein synthesis?

  transcription and translation
• what is the theory of Dispersive replication?

  where half the nucleotides are placed randomly in the DNA being replicated to make new molecules which would give successively lighter molecules and therefore a band between hybrid and light in generation 2.
• what is the theory of Conservative replication?

  direct copying of the nucleotide sequence onto a new double stranded molecule which would give one light and one heavy molecule in generation 1.
• what is the theory of semi-conservative replication?

  each strand in a DNA molecule serves as a template for synthesis of a new, complementary strand
• what are the stages of DNA replication?

  1. DNA helicase breaks the hydrogen bonds between the bases in the double helix.

  2. This unwinds the DNA and exposes unpaired bases.

  3. Free nucleotides in the nucleoplasm are bound to their complementary bases on the unzipped strand.

  4. DNA polymerase joins the nucleotides together by condensation reactions between sugar and phosphate groups of adjacent nucleotides.

  5. Eventually, 2 new DNA molecules are formed from 1 new and 1 old strand of the DNA. This is called semi-conservative replication.
• what are the differences between RNA and DNA?

  RNA- Ribose sugar DNA-Deoxyribose sugar

  RNA- Single stranded DNA- Double stranded

  RNA- A,U,C,G bases DNA- A,T,C,G bases

  RNA- Short polynucleotides

  DNA- Long polynucleotides
• what does Guanine pair up with?


  cytosine
• what does adenine pair up with?

  Thymine
• what are the two types of DNA bases?

  Purines: Adenine and Guanine

  Pyrimidines: Thymine and Cytosine
• What is the structure of DNA?

  DNA is made from one strand of nucleotides linked by hydrogen bonds between the bases to another strand that runs antiparallel to the first. in a double helix structure
• describe rRNA

  forms ribosomes
• describe tRNA

  carries an amino acid at the 3' end and an anticodon arm to attach to the mRNA
• describe mRNA

  made as a complementary copy of the DNA genetic code in the nucleus during transcription. The molecule length is related to the length of the gene transcribed. It attaches to a ribosome in the cytoplasm.
• what are the different types of RNA?

  mRNA, tRNA, rRNA
• what is the structure of RNA?

  RNA nucleotides are linked together in a single-stranded polynucleotide
• how does ATP release energy?

  ATP releases energy in one hydrolysis reaction controlled by one enzyme. ATP releases energy in small, usable amounts. ATP travels easily to where it may be used for secretion, muscle contraction, nerve transmission or active transport.
• what is ATP used for?

  'universal energy currency' and is used to provide energy for all biochemical reaction in all living organisms
• what is the general structure of nucleic acid?

  pentose sugar, a phosphate group and a nitrogenous base