Effects of caffeine

• What is the main purpose of the experiment with Daphnia?

  To investigate the effect of caffeine on heart rate
• How does caffeine affect heart rate in humans?

  It increases heart rate by increasing neurotransmitter release
• Why are Daphnia used in this experiment?

  They have a translucent body for heartbeat observation
• What equipment is needed for the experiment?

  • Daphnia
  • Cavity slides
  • Dropping pipettes
  • Distilled water
  • Caffeine solution
  • Cotton wool
  • Test tubes
  • Stop clock
  • Filter paper
  • Optical microscope
• What is the first step in the method for the experiment?

  Dilute caffeine solution with distilled water
• Why should cotton wool be used on the cavity slide?

  To restrict movement of the Daphnia
• What should be done with the water around the flea?

  Use filter paper to absorb it
• Why should a coverslip not be used during the experiment?

  To prevent conditions from becoming anoxic
• How long should the heartbeats be recorded for?

  One minute
• What should be done after recording heartbeats with distilled water?

  Repeat with caffeine solution
• What are the risks associated with the experiment and their precautions?

  • Biohazard: Use disinfectant; wash hands after handling Daphnia
  • Broken glass: Handle glassware carefully; keep away from edges
• What should be done in case of a biohazard risk?

  Use disinfectant and wash hands
• What is the conclusion regarding caffeine's effect on Daphnia heart rate?

  Caffeine increases heart rate by increasing neurotransmitter release
• What should be done with Daphnia after the experiment?

  Release them back into a stream or pond
• What is the relationship between caffeine concentration and heart rate in Daphnia?

  • As caffeine concentration increases, heart rate also increases
  • Caffeine increases the release of stimulatory neurotransmitters
• What type of organism is Daphnia?

  Water flea
• What is the significance of using a stop clock in the experiment?

  To accurately time the heartbeat recording
• What is the risk level associated with biohazard in this experiment?

  Low
• What is the risk level associated with broken glass in this experiment?

  Low