1/2/3 markers in biology

• what does peer reviewing do?

  prevents false claims before a hypothesis is published
• 2 types of theory models?

  representational e.g lock and key computational e.g climate change
• what are limitations to models?

  taking all biological and chemical processes into account
• what can happen to media communication ?

  • biased or not providing evidence against their claim OR inaccurate and misinterpreted
• what are four issues of working scientifically ?

  economical, social, individual, environmental
• what is a risk?

  chance that a hazard may cause harm e.g nanoparticles in sin cream . have to determine if risks outweigh the benefits
• what does evidence need to be?

  repeatable (3x). reproducible by doing a second set of readings with different instruments and VALID.
• what is the difference between accuracy and precision?

  accuracy means true to real answer , precision is when your answer is close to the mean of repeated results
• what is the resolution?

  smallest change a measuring instrument can detect e.g 1mm in a ruler
• 3 types of errors?

  1. RANDOM- human error in measuring, repeat
  2. SYSTEMATIC- measurement wrong by same amount every time
  3. ZERO- equipment isn’t zeroed properly
  4. ANOMALOUS - ignore it
• what do you do if your data is categoric?

  use a bar chart with linear y axis, labels, title and even gaps
• what do you do if your data is continous?

  use a graph
• how do you get from millimetres to micrometers ?

  Multiply by 1000
• how do you get from micrometers to nanometers?

  multiply by 1000
• correlation..?

  doesnt equal cause!! correlation can be by chance, third variable or Cause
• how do you measure uncertainty ?

  range/2
• how do you reduce uncertainty?

  measure a greater amount
• how do you use a water bath?

  1. set temperature and allow it to heat up
  2. use a thermometer
  3. use testube holders or tongs to hold above water
• how do you use a potometer?

  1. cut shoot underwater to prevent air entering and cut at a slant for a larger surface area
  2. assemble in water
  3. remove apparatus from water but keep capillary tube submerged in beaker
  4. check it is water and air tight
  5. dey the leaves and left shoot acclimatise and shut the tap
• how do you measure the size of a single cell?

  1. clear plastic ruler on top of slide clipped with a stage
  2. use magnification of 100x
  3. adjust focus
  4. move ruler to align with 1mm
  5. 1 mm = 1000 micrometers
• why will blood around your brain cool if you drink cold water?

  blood is cooled at the mouth/stomach and flows to the brain
• finish the lyric..?

  • blood enters the kidneys via filtration
  • glucose is not found in the urine because of reabsorption
  • urine is removed from the body via excretion
• why arent children aged 4 6 and 9 genetically identical?

  1. different sperm/egg used each time
  2. different genes and dna from both parents
• why is the human genome important?

  • helps track migration patterns
  • detect genetic/inherited disorders
  • gene therapy
• what are nutrients needed for?

  to make proteins or chlorophyll for energy
• why are plant hormones used?

  to stimulate differentiation/cell division so roots or shoots develop
• why is asexual reproduction useful?

  • time efficient
  • energy efficient
  • passes down beneficial characteristics
• why is using stem cells from same umbilical cord ideal?

  perfect tissue match
• why cant you treat a genetic disorder with the same stem cells from its umbilical cord?


  stem cells have the same faulty gene/DNA/chromosomes
• what is a fossil?

  remains of an organism from a long time ago
• causes for extinction?

  • flooding,drought,global warming, volcanic activity, predators, disease, competition
• three reasons fossil record isnt clear?

  fossils smaller and buried deeper so harder to find

  soft bodied decay

  geological activity
• why might using mean from quadrats be inaccurate?

  • too few/small quadrats and the sample may not be a representative of the lawn
• how to increase quadrat mean accuracy?

  repeat with more sample areas

  calculate actual percentage

  only count those over 50%

  divide quadrat into smaller squares
• use of nitrates vs magnesium ions?


  nitrates are used to make proteins which are used to mae growth and repair. magnesium ions are used tomake chlorophyll a substance in chloroplasts to absorb light needed for photosynthesis
• food test for lipids using ethanol?

  add a few drops of ethanol shake and leave for a minute it should turn cloudy when in a tube of water