Unit 3 and 4

• Variation:

  Variation exists between individuals’s phenotype in a population.

  Selection pressure:

  An environmental selection pressure impacts the survivability of individuals in the population and their ability to produce.

  Selective advantage:

  Individuals with fitter alleles or advantageous alleles that undergo the environmental selection pressure are able to survive and reproduce more successfully.

  Heritability:

  The advantageous trait must be heritable, allowing it to be passed on from the parents to their offspring. Therefore, over time, the frequency of the advantageous allele will increase.
• CREATING CRISPR CAS9 


  1. Locate target DNA sequence by using DNA synthesiser
  2. Create a single strand guide RNA complementary to the target DNA sequence
  3. Combine gRNA, CAS 9, and PAM sequence to make CRISPR CAS 9 complex
  4. USE CAS 9 to cut the specific recognition site of the target DNA sequence if PAM is present
• What is the first step in creating insulin?

  Isolate the gene of interest through a DNA synthesiser
• What is the purpose of preparing a plasmid in the insulin creation process?

  To include an antibiotic resistance gene and a lac Z gene
• Which endonuclease is used in the process of creating insulin?

  The same endonuclease is used to cut out the insulin gene and the plasmid
• What is the effect of cutting the plasmid with the endonuclease?

  It disrupts the Lac Z gene's production of blue pigment
• What role does ligase play in the insulin creation process?

  It binds the phosphodiester bond between the insulin gene and the plasmid
• What happens to plasmids that have taken up the insulin gene?

  They will grow clear, indicating they are now recombinant plasmids
• How is the permeability of bacteria's plasma membrane increased during the insulin creation process?

  By using heat shock
• What is the purpose of preparing an agar/culture plate with an antibiotic?

  To expose bacteria to initiate growth and replication
• What indicates that bacteria have survived the antibiotic treatment?

  Those which are clear have the insulin gene
• What is the next step after exposing bacteria to the antibiotic on the agar plate?

  Incubate to allow the insulin to grow and replicate
• What is repeated for insulin B in the insulin creation process?

  Steps 1-7
• What is the final product created by combining insulin A and B?

  A quaternary and functional insulin
• What are the key steps in the process of creating insulin?

  1. Isolate gene of interest through DNA synthesiser
  2. Prepare a plasmid with antibiotic resistance and lac Z gene
  3. Cut out insulin gene and plasmid with endonuclease
  4. Ligate insulin gene to plasmid
  5. Use heat shock to increase plasmid intake in bacteria
  6. Prepare agar plate with antibiotic and expose bacteria
  7. Incubate to allow insulin to grow and replicate
  8. Repeat for insulin B
  9. Combine insulin A and B for functional insulin
• Cellular respiration

  CHEMICAL EQUATION


  C6H12O6  +  6O2  --> 6CO2 + 6H2O + 30 or 32 ATP
• Cellular respiration

  WORD EQUATION

  Glucose + Oxygen --> Carbon dioxide + Water + ATP
• Aerobic Cellular respiration Locations

  -        Glycolysis (in the cytosol)

  -        Krebs cycle (in the matrix of the mitochondria)

  -        Electron transport chain (in the cristae of the mitochondria)
• Bottleneck effect


  Reduces genetic diversity through the removal of alleles due to random events (e.g. natural disaster)
• Founder effect


  Reduces genetic diversity through the establishment of a new population with a small unrepresentative sample of the original population
• Reductions in genetic diversity have two major risks:

  • Inbreeding – this keeps harmful alleles in the gene pool.
  • Lower adaptive potential – populations become vulnerable to new selection pressures that could challenge due to the absence of advantageous alleles.
• An anabolic reaction is when two or more smaller molecules combine to form a larger one (i.e. building things up)
• A catabolic reaction is a larger molecule turning into two or more smaller molecules (i.e. breaking things down).
• How are monoclonal antibodies produced?

  1. Scientists identify and isolate an antigen from a target cell.

  2. They vaccinate mice with the antigen, promoting the selection and proliferation of matching B lymphocytes.

  3. B lymphocytes are extracted from the mice's spleens.

  4. These B lymphocytes are fused with rapidly-dividing myeloma cells to create hybridomas.

  5. Hybridomas are screened to select those producing the desired antibody.

  6. Antibodies are collected, purified, and administered to patients.
•  

  Antigens are molecules that are recognised by the immune system.
• Self-antigens, self markers (proteins) expressed by the body’s own cells are recognised by MHC receptors and left alone
• Non-self antigens, not expressed by the body (molecules on the surface of bacteria, toxins, viruses) are recognised by MHC receptors as foreign and an immune response launched
• Allergens are antigens that the immune system to produce an abnormal and inappropriate overreaction when a person is exposed. Immune system reacts abnormally to substances in the environment that are harmless to most people, eg pollen. Produce and allergic response rather than a normal immune response.
• MHC class 1 – found on the surface of all the body’s nucleated cells
• MHC class 11 – found on the surface of specific immune cells such as dendritic cells and macrophages that act as antigen presenting cells (APCs)
• Acellular pathogens: Virus, Prions
• Cellular pathogens: Bacteria, Parasites, fungi