Essay
Unit 6 - Investigative Project learning aim A
- Institution
- PEARSON (PEARSON)
Unit 6 - Investigative Project learning aim A
[Show more]
Content preview
Unit 6A: Scientificinvestigation
Effects of caffeine on the heart rate of daphnia
Introduction
This project proposal will investigate the effects of caffeine on the
heart rate of daphnia. Caffeine is a compound that occurs naturally
and is soluble in both oil and water. It is generally extracted from
leaves beans and fruits of plants (mostly coffee beans, cocoa beans,
and tea leaves). Scientifically caffeine is classified as a recreational
drug even though its effects are milder than other recreational drugs
like cocaine amphetamines and heroin. So, it is used all around the
world to make different kinds of foods and drinks like tea, coffee,
and energy drinks. When daphnia is exposed to caffeine their heart
rate increases as with the concentration this is because caffeine can
block receptors on the surface of the heart muscle cells. Caffeine
which is known as 1,3,7-trimethyl xanthine in chemistry binds to the
receptors on the surface of the heart muscles and increases the level
of cAMP inside the cells, causing an increase in the heart rate. This
result in an overall increase in the rate of glycolysis and the amount
of ATP available for muscle relaxation and contraction. Caffeine also
inhibits a class of enzymes called cyclic nucleotide
phosphodiesterase. (Robertson, D., Frölich, 1978) Part of these
enzymes’ responsibility is to degrade a stimulatory signal produced
when excitatory neurotransmitters activate neurons in the CNS. So, if
caffeine inhibits them, the stimulatory signal remains active for a
longer time, resulting in a greater sense of alertness and higher
blood pressure, higher respiratory rate, and higher heart rate.
Caffeine also causes an increase in stimulatory neurotransmitters to
be released. Neurotransmitters are the key mediators of
communication between nerve cells. In my research, daphnia is used
to investigate how its heart responds to caffeine and its chemicals.
, daphnia is a tiny crustacean that has a clear outside skeleton, they
are very small with lengths between 0.2- 5 mm. They are one of the
several small aquatic organisms called water fleas because of their
jumpy swimming style.
They have hearts that are comparable to human hearts. Daphnia has
a myogenic heart meaning their heart rhythm is controlled or
generated by a specialized muscle in the heart rate. Daphnia also has
a transparent body which can easily allow us to see its heart with a
microscope while it is alive. There is no threat to daphnias’ existence
or reproduction as they reproduce asexually as clones. Their central
nervous systems are not as developed as humans/vertebrates
therefore they are not self-aware. The type of daphnia used is
daphnia magma. The rationale behind this research was that
caffeine is known to affect/alter the nervous system functions and if
the level of consumption is high enough caffeine is known to cause
restlessness, anxiety and insomnia which causes raised blood
pressure and stress. And to research this a live and unhurt subject is
needed. Therefore, daphnia is used in this research as we can see the
effects without making any other change to the surroundings or the
daphnia itself.
Aim
To investigate the effect of caffeine on the heart rate of daphnia
Hypothesis
The concentration of caffeine will affect the heart rate of daphnia
accordingly which means if the caffeine concentration increases the
heart rate of daphnia will increase same goes for the opposite.
Objective & technique
The objective is to test how caffeine and its chemicals affect the
heart rate of daphnia (magma). this is done by observing and
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller MikasaAckerman. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £11.39. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
78600 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy revision notes and other study material for 14 years now