good exam ans

• Explain the role the adrenal glands play in maintaining blood glucose levels:

  • adrenal cortex secretes cortisol/glucocorticoids
  • stimulates the conversion of glycogen into glucose/glycogenolysis in liver
  • increases the rate that amino acids are removed from muscle cells (and taken to liver)
  • amino acids converted into glucose/gluconeogenesis by liver
  • increase movement of fatty acids from adipose tissue to muscle cells for use
  • adrenal medulla produces adrenaline/noradrenaline
  • stimulates production of lactic acid from glycogen in muscle cells
  • lactic acid converted to glucose in liver
• Explain how the theory outlined implies that natural selection occurred in the process of Homo sapiens replacing Homo neanderthalensis

  • when Homo sapiens invaded Homo neanderthalensis territory there must have been a struggle for survival/competition for resources/not enough resources for both
  • Homo sapiens were better adapted to the environment/most ‘fit’ species/had immunity to diseases of both populations
  • the strongest (Homo sapiens) were able to survive to reproduce/the weakest (Homo neanderthalensis) did not survive to reproduce
• Explain how cell replacement therapy aims to help Alzheimer’s sufferers:

  • replace the damaged cells/neurons with healthy stem cells
  • that can create new healthy brain cells
  • stem cells may reduce protein deposits/may halt progression of the disease
• Explain why presenting the data with only the mean and not including the median scores can be misleading:

  • the mean does not indicate the spread of the results/cannot show if the results are skewed/can be influenced by outliers
  • when the median is included the distribution of results is clearer/can show if the results are normally distributed
• Recall the evidence that phylogenetic trees illustrate

  • represent evolutionary relationships between organisms
  • reflect how recently species evolved from common ancestors
  • more recent common ancestors indicate more closely related species
  • less recent common ancestors indicate less closely related species
  • hypotheses of the relationships/not facts/possible relationships/ possible pathways
• Explain how vaccines produce immunity to a pathogen

  • contain antigens
  • B cells are activated
  • produce plasma cells and memory cells
  • plasma cells produce antibodies
  • memory cells remain (spread through the lymph)
  • if they encounter the antigen again
  • they produce more antibodies quickly
  • individuals usually do not show symptoms
• Explain how an index fossil can be used to date another fossil

  • index fossils have a known date/age range
  • due to widespread but limited time span they exist
  • if found with other fossils, age can be correlated
• Explain the role of a transgenic organism, or genetically-modified organism, in the recombinant DNA

  • plasmids with the inserted gene of interest
  • to produce the desired protein/vaccine
  • in large quantities/quickly/cheaply