L4-6 quiz

• transforming principle AKA


  DNA
• Avery and his co-workers showed the transforming principle as DNA
• the genetic code is read without any commas
• bases are read in groups of 3, beginning with the start codon
• an amino acid can have multiple codons code for it
• AUG codes for the amino acid methionine and the start codon of translation
• genetic code is the same in all organisms with a few exceptions
• gene expression involves 


  transcription and translation
• gene expression is the flow of information from DNA to mRNA to protein
• transcription is the synthesis of RNA from DNA template
• translation is the synthesis of protein using the code held in mRNA
• bond that forms between the newly added amino acid and the previous amino acid on the chain is called a

  peptide bond
• enzyme that carries out transcription is

  RNA polymerase
• the most common condition of trisomy is of chromosome

  21
• trisomy is when


  3 copies of chromosome are present instead of the normal 2
• the sites A, P and E are progressively occupied by amino acids being assembled into a chain in protein synthesise
• A, P and E are sites that are part of the large ribosomal subunit
• large ribosomal subunit contains the tRNA binding sites
• DNA replication involves the separation of the 2 strands
• each strand of DNA is used as a template to make a new strand of DNA
• tRNA molecules are approximately 80 nucleotides in length
• activating enzymes called amino-acyl tRNA synthetases attach specific amino acids to their tRNA
• Hershey-Chase experiment: 1952, found that DNA is a double helix
• Hershey-Chase experiment:

  • DNA labelled with radioactive phosphorus
  • protein labelled with radioactive sulfur
  • virus-infected bacteria showed radioactive phosphorus
  • virus-infected bacteria contained no radioactive sulfur