• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Effect of caffeine on heart rate on Daphina

Extracts from this document...


Effects of caffeine on the heart rate of daphnia Aim: to observe the effects of different concentrations of caffeine on the heart rate of daphnia. Null hypothesis: caffeine has no effect on the heart rate of daphnia. Alternative hypothesis: as the concentration of caffeine increases so does the heart rate of daphnia. Scientific background: Caffeine is a nerves cell stimulant that increases heart rate by the stimulation of cardiac cells. Caffeine does this by blocking adenosine, a neurotransmitter that allows the body to relax. This blockage results in the adrenal gland to release adrenaline hormone, this causes the heart rate to increase, pupils to dilate, your muscles to tighten up, and glucose is released into the blood stream for extra energy. Caffeine also increases dopamine; this activates pleasure parts of the brain which activates the caffeine addiction. Over excess drinking of caffeine could result in restlessness, headaches, and increases blood pressure. Over a long term as the body gets used to the amount of caffeine, it needs higher concentrations for more energy, releasing more and more hormones. ...read more.


4. Place it under the microscope and count how many times its heart beats in 30 seconds on the stop clock. 5. When 30 seconds has past, stop the clock and record the heart beats in a table. 6. Repeat the sample 3 times with distilled water and record the results. 7. Repeat the method with 0.19% of caffeine concentration on another daphnia, and repeat the sample 3 times then record the results. 8. Do the same with 1.59% caffeine concentration and record the heart beats per 30 seconds on the table. The dependent variable in this experiment is the number of daphnia?s used to determine the increase in heart rate. And the independent variable is the concentration of caffeine used and the different sizes of daphnia used for each sample of caffeine. Repeat: for most of the results, three samples were made for each concentration of caffeine, to ensure that the results are as accurate as possible. ...read more.


This proves that the heart beat was gradually increasing as the concentration of caffeine was. The only anomaly shown is the second 0.19% caffeine solution result (60seconds). Evaluation: The method used did have some limitations like the different sizes of daphnia used for different concentrations of caffeine, some where smaller than others making it harder to read their pulse rate. And some further more active than others making it harder for the experimenter to count the number of heart beats per second. The method overall was accurate enough to use, however more repeats could have been done to ensure reliability of data, on the other hand the equipment used wasn?t as reliable to give accurate results, a device for counting all the heart beats were used their would be less errors in results due to the fact that the experimenter could have made a mistake. The results of the experiment raise questions like could the same effects seen on the daphnia apply to a human heart, and if so then what concentration would show a risk to the health of an individual. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Energy, Respiration & the Environment section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Energy, Respiration & the Environment essays

  1. Marked by a teacher

    Effect of nitrate concentration on the growth of Duckweeds

    5 star(s)

    Each duckweed used was from the same pond, this increased the reliability of the results, because before staring the experiment the duckweeds all had the same nutrients and components inside the cells. As if they were all from different ponds, they may have been polluted and contained different nutrients inside them which could affect their growth rates.

  2. Marked by a teacher

    How caffeine affects Daphnia heartbeat?

    4 star(s)

    The group labelled should be used as anomalies as they do not fit in with the trend of the rest of the results, this will make the average more inaccurate.

  1. the effect of bile concentration on the activity of the enzyme lipase during the ...

    temperature is a variable we have to control pH Probe Used to measure the pH change whilst the reaction is taking place. Accurate and way of measuring pH because pH probe will be set to pH 7 by using a pH buffer of 7 so the probe will be accurate

  2. Investigating the effects of Sodium Hydroxide concentration on Catalase

    level as the 40 second mark at 19.6cm�, and this could be due to the fact that the enzyme have not react will any substrate during this time or that the gas syringe has got stuck, which also could of caused it.

  1. Investigation into the Effect on Pulse Rate & Breathing Rate During

    The heart rate will always increase when special demands are placed upon it, such as exercise. Since faster blood flow increases the rate at which fresh blood reaches the body cells, more oxygen and glucose are made available to them during periods of stress.

  2. Investigate the effect of bile salt concentration on the digestion of milk by the ...

    The final prediction graph that I will make is the activity of lipase against the substrate concentration. The reason I will plot these two variables is because the bile actually acts on the substrate and emulsifies it increasing the surface area.

  1. Effects of different concentrations of ethanol on the heart rate of the water flea

    Each Daphnia will stay in the ethanol solution for exactly 3 minutes so that an equal volume of ethanol is absorbed. Activity of Daphnia - Some Daphnia tend to be more active than others and these will have a higher heart rate compared to ones that are idle.

  2. Affect of caffeine on heart rate of Daphnia

    The variables which we will be keeping the same are the volume of concentration, this is because by having different volumes of caffeine, the concentration level will be altered and this will not give us valid results. The size of the flie will have to be the same, as this

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work