# effect light intensity cyclosis elodea leaf cells

Research Question: What is the effect of light intensity on the speed of movement of chloroplast (rate of cyclosis) in Elodea?

* Independent variable; Light intensity (Lux)

* Dependent variable; time taken for a chloroplast to move a measured distance. (s)

* Controlled variables; temperature (oC), volume of water (mm3), using same leaf, CO2 (ppm.)

Hypothesis: As light intensity exposed on an Elodea cell increases, rate of cyclosis inside the cell increases.

Apparatus used:

* Glass slides to view specimen

* Elodea leaf (fresh from plant)

* Microscope

* Stopwatch

* 3 lamps

Procedures:

One leaf was taken from an Elodea plant and examined under a light microscope at a magnification of around 400x. A cell was then located which performed cyclosis, and was exposed to the light produced by 1 lamp. 5 recordings were taken of the time taken for one chloroplast to move from one end of the cell to the other. This procedure was repeated with 2 lamps and 3 lamps giving 15 readings. The cell length was then measured by finding the length being viewed under the magnification and divided by the number of cells that fit into that length.

Interpretation:

The graph shows a trend where the rate of cyclosis increases (generally) as light intensity increases (i.e. when increasing the number of lamps) because graph lines of ‘speed with 3 lamps’ or speed of chloroplast with light from 3 lamps is higher than with 2 lamps or 1, and the speed of chloroplast is greater with 2 lamps than 1 lamp because its line is above the line for 1 lamp.

Errors:

Random errors: As seen in the graph, the 5th measurement of ‘speed with 3 lamps’ was an extreme value due to a large ‘pileup of chloroplasts inside the cell leading to a very long time taken for the chloroplast to move the required distance. In addition, the temperature at which the experiment took place was not controlled, water supply was not monitored and the CO2 concentration was not taken into account.

Human errors: The 12th reading of 1 lamp may have human attention span/concentration error since the time measured was much shorter than the average time taken by chloroplast (i.e.) by mistaking another chloroplast for the original while measuring, leading to a different measurement. Breathing onto the specimen alters the CO2 concentration and so alters the result. Uneven number of recordings were made due to bad time management.

Systematic errors: A systematic error in the experiment came in the controlled variable, since the brightness of each lamp is not exactly the same and not equal amounts of light of each lamp reaches the sample. The instrument used to measure the length of a cell was also not accurate because, at high magnification the division lines are very thick and so it is impossible to accurately measure the size of the cell.

Improvements:

This investigation can be made to give more accurate results by controlling temperature, water supply, controlling CO2 concentration and by using the same leaf cell for all measurements. To control temperature, the experiment can be carried out in a closed laboratory with no air circulation. Temperature can be measured periodically to make sure temperature stays constant. Water supply can be controlled by keeping a drop of water next to the specimen and using blotting paper to suck water into the slide. CO2 concentration can be controlled by not breathing onto the specimen and keeping it in a closed container. Using the same leaf avoids differences in measurements due to different chloroplast concentration or size of the cell.

Conclusion:

Through this experiment one can conclude that the rate of cyclosis increases as light intensity increases. The graph formed by the collected data shows how the speed at which chloroplast moves in increasing light intensities increases. The data thereby supports the hypothesis as chloroplast moved at an average of 6.36um/s while being exposed to the light of one lamp but 8.96um/s with 3 lamps. Though there were some extreme values, they can be accounted for by the errors explained earlier.

### "Looking for a Similar Assignment? Order now and Get a Discount!

Pages (550 words)
Approximate price: -

Why Work with Us

Top Quality and Well-Researched Papers

We always make sure that writers follow all your instructions precisely. You can choose your academic level: high school, college/university or professional, and we will assign a writer who has a respective degree.

We have a team of professional writers with experience in academic and business writing. Many are native speakers and able to perform any task for which you need help.

Free Unlimited Revisions

If you think we missed something, send your order for a free revision. You have 10 days to submit the order for review after you have received the final document. You can do this yourself after logging into your personal account or by contacting our support.

Prompt Delivery and 100% Money-Back-Guarantee

All papers are always delivered on time. In case we need more time to master your paper, we may contact you regarding the deadline extension. In case you cannot provide us with more time, a 100% refund is guaranteed.

Original & Confidential

We use several writing tools checks to ensure that all documents you receive are free from plagiarism. Our editors carefully review all quotations in the text. We also promise maximum confidentiality in all of our services.

Our support agents are available 24 hours a day 7 days a week and committed to providing you with the best customer experience. Get in touch whenever you need any assistance.

Try it now!

## Calculate the price of your order

Total price:
\$0.00

How it works?

Fill in the order form and provide all details of your assignment.

Proceed with the payment

Choose the payment system that suits you most.

Our Services

No need to work on your paper at night. Sleep tight, we will cover your back. We offer all kinds of writing services.

## Essay Writing Service

No matter what kind of academic paper you need and how urgent you need it, you are welcome to choose your academic level and the type of your paper at an affordable price. We take care of all your paper needs and give a 24/7 customer care support system.

An admission essay is an essay or other written statement by a candidate, often a potential student enrolling in a college, university, or graduate school. You can be rest assurred that through our service we will write the best admission essay for you.

Editing Support

Our academic writers and editors make the necessary changes to your paper so that it is polished. We also format your document by correctly quoting the sources and creating reference lists in the formats APA, Harvard, MLA, Chicago / Turabian.

Revision Support

If you think your paper could be improved, you can request a review. In this case, your paper will be checked by the writer or assigned to an editor. You can use this option as many times as you see fit. This is free because we want you to be completely satisfied with the service offered.

Get better grades effortlesslyIt’s cheaper than you might think

Effortlessly get the essays and grades you need. You can now get any essay, on any subject and at ANY deadline with just 10 minutes of your time (or less). Your professor will love you for it!