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• what is DNA sequencing? 


  finding the nucleotide sequence for a gene or the whole genome
• how is DNA sequencing carried out?

  create copies of DNA fragments, create complementary DNA fragments and analyse complementary DNA fragments
• what is the function of Gel electrophoresis?


  separates molecules of DNA, RNA and proteins
• what is gel electrophoresis used for?

  genome sequencing and DNA profiling
• what is genetic engineering?

  the process of isolating one organism and inserting it into another organism.
• what are the different uses of genetic engineering?

  gene therapy, modify plants, modify pathogens and pharming
• what is somatic gene therapy?

  gene inserted into somatic/body cells where they target tissues that need treatment
• what is germ-line gene therapy?


  where the gene is inserted into germ cells/gametes, which are then inherited.
• what are the pros of DNA sequencing?

  reveals relatedness, reveals tertiary structures, useful for synthetic biology where new drugs are developed
• what is one way of producing DNA fragments?


  with the use of the enzyme restriction endonuclease
• what is the function of a restriction endonuclease?


  it is able to recognise a specific recognition sequence
• where are restriction endonuclease obtained from?


  from bacteria cells where they're used to break down the DNA inserted into the host cell by the pathogen preventing the pathogen from taking over.
• how are the DNA fragments cut with the use of the restriction endonuclease?


  by breaking the phosphodiester bonds between adjacent nucleotides
• what is another method of producing DNA fragments?

  using mRNA to reconstruct the DNA fragments
• what is the function of the enzyme reverse transcriptase?


  it binds to the mRNA molecule and moves along while adding complementary DNA nucleotides to the exposed complementary bases.
• what is produced when the reverse transcriptase enzyme has added on nucleotides to all bases?

  a complementary DNA is produced (cDNA)
• what does DNA polymerase do?

  adds on DNA complementary nucleotides to exposed bases
• how is DNA transferred to genetically modify an organism?


  via a vector e.g, for bacteria, it is inserted into a plasmid
• explain the role of DNA ligase during genetic engineering.


  DNA ligase is responsible for joining together the nucleotides of the DNA fragment with the nucleotides of the plasmid by catalysing the formation of phosphodiester bonds
• Explain why the same restriction endonuclease must be used to produce on both the DNA fragment and the plasmid during genetic engineering.


  as it would cut at the same recognition sequence therefore resulting in both the DNA fragment and plasmid's sticky ends to be complementary to each other.
• why is the DNA fragment not completely bound to the plasmid when the restriction endonuclease is used in genetic engineering?


  as it has allowed the complementary bases to join via hydrogen bonds however the sugar-phosphate backbone is still separated/has gaps.
• what is the term used to describe a complete plasmid and DNA fragment?

  recombinant plasmid
• Describe and explain the process of transformation during genetic engineering.

  Transformation is the process in which a plasmid is added to a host cell.One method of transformation requires the addition of calcium ions to the mixture, and heat shock in order for plasmids to pass through the cell surface membranes of bacteria. A second method is electroporation.
• why can't recombinant plasmids pass through the cell membrane of a bacterium?

  as they consist of DNA, which are polar charged and hydrophilic
• why might a recombinant plasmid not enter a bacterium?


  the plasmid may join up without incorporating the DNA fragment, DNA fragments may join up together and be recognised as a foreign cell or the bacterium won't take up the recombinant plasmid
• what is the process of the plasmid entering the host cell called?

  transformation
• how do scientists recognise the bacteria that contain the recombinant plasmid?

  using an antibiotic resistance marker gene
• what marker gene examples can be used to identify which gene consist of the recombinant DNA?

  antibiotic resistance, fluorescent and enzyme
• what's an example of an enzyme marker gene?

  lactase producing gene
• what are the three features of the genetic code?

  it's universal, degenerate and non-overlapping
• give two reasons why it is easier to obtain genes from mRNA, rather than directly from the DNA removed from human cells.

  mRNA is present in larger amounts, doesn't contain introns, codes for a single protein
• what does a polymerase chain reaction (PCR) do?


  produces copies of DNA fragments in a continuous cycle
• what does a polymerase chain reaction (PCR) require?


  DNA fragment, DNA polymerase (Taq polymerase), DNA nucleotides and DNA primers
• what is the process of a polymerase chain reaction (PCR)?


  the DNA fragment is heated to break the hydrogen bonds between bases and separate the strands, then the temp is reduced enabling primers to attach to complementary bases at the ends of strands, temp is increased again and with the help of primers, taq polymerase adds on complementary bases
• what is DNA profiling?

  analyses and compares STRs (short tandem repeats) between two or more individuals
• what is DNA purification?


  where proteases are added to DNA to remove histones
• what are four uses of DNA profiling?


  to analyse risks of certain diseases, identify suspects, identify closely relating species and to determine genetic diversity
• what is the overall yield of glycolysis per 1 glucose molecule?


  2 ATP, 2 NADH and 2 pyruvate molecules
• what is the overall yield of the link reaction per 1 glucose molecule?



  2 CO2 molecules, 2 NADH and 2 acetyl coA molecules
• what is the overall yield of the Kreb cycle per 1 glucose molecule?



  2 CO2, 6 NADH, 2 ATP molecules and 2 FADH2