• Join over 1.2 million students every month
• Accelerate your learning by 29%
• Unlimited access from just £6.99 per month
Page
1. 1
1
2. 2
2

# Aim: To estimate the solute potential of a plant tissue.

Extracts from this document...

Introduction

Solute Potential of Cell Sap of Plant Epidermal Cells Aim: To estimate the solute potential of a plant tissue. Results: Molarity of Solution Plasmolysed Cells Percentage of Cells That Were Plasmolysed .3M 1/70 .01% .4M 0/70 0% .5M 5/70 7% .6M 12/70 17% .7M 29/70 41% 1.0M 56/70 80% It must be taken into account, that the experiments procedure was changed. This could have had a great affect on the results. The part of the procedure that was changed was the time. Instead of the epidermal cells being left in the solutions 20 minutes, they were left for a day. Not only, were they left much longer, but the molarity of the solutions could have also changed since they were left uncovered for over 24 hours and some of the water could have been evaporated. ...read more.

Middle

The most contracted membranes were found in epidermal cells that were left in the solution with the greatest molarity; in this case it was the cells that were left in the solution with a 1.0 molarity. The graph shows a constant start. It very quickly shoots up, with a huge leap from .6Mto 1.0M. The results for this experiment did not come back exactly the way they should have to prove the point. In the epidermal cells that were placed in the .3M solution .01% of the cells plasmolysed, but in the epidermal cells that were placed in the .4M solution 0% of the cells were plasmolysed. If the experiment had gone exactly as planned, the cells that were placed in the .4M solution would have had more than .01% cells plasmolysed. ...read more.

Conclusion

Another error that could have occurred, and that would explain what happened to the cells that were put in the solution with .4M, is that onion skin dried out before it was placed in the sucrose water. Also, there could have been a variation between the different onion epidermis cells that were used, because not all cells in the same tissue have the same solute potential. Next time, to avoid these errors, the correct time should be used. The pieces of onions should be cut more exactly and each cell that is visible through the microscope should be counted. To evade to possibility of the onion cells drying out they should be immediately placed into the sucrose solution. Also, during the waiting period the solutions that the cells are in should be covered, as to avoid any evaporation that may occur. ...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 Molecules & Cells section.

## Found what you're looking for?

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

## Here's what a teacher thought of this essay

**Results and conclusion only.
This piece of work fails in many key aspects that are considered good practice at A level and the data collected cannot be considered to be valid due to problems with the methodology.

To improve:
There is no real attempt to provide a rationale for the choice of investigation in terms of its scope,and its relation to biological principles. The hypothesis should be stated and biological knowledge used to explain a prediction.
Attempts to interpret the data are not linked to any researched information. The candidate needs to include carefully selected reference material to help inform the conclusion.
There is no relevant biological background. The conclusion would be expected to refer to the water potential of the relevant solutions and discuss the movement of water molecules in the solution.
No graph was included and the description of the underlying trends would be helped by the use of technical or scientific language. The solute potential of the cell sap needs to be calculated ( obtained from the graph at 50% plasmolysis) as this was the stated aim of the experiment.
The analysis of the method reveals a catalogue of very poor planning. Detailed suggestions for improvements and extensions would have improved this section.

Marked by teacher Stevie Fleming 22/08/2013

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

# Related AS and A Level Molecules & Cells essays

1. ## Observing Mitosis. The purpose of this experiment is to prepare a slide of actively ...

3 star(s)

In our slide we saw a few different stages of mitosis but ours wasn't very clear and this could have been for various reasons. We might not have macerated it sufficiently, might not have been looking at the meristem or maybe not stained the cells enough.

2. ## The Strength of Plant Fibres

For all three trials, the celery fibre held a weight of 100g. Therefore, this fibre isn't that good and reliable for commercial uses. This is why it's not used for products. Instead, its uses include a vegetable for eating, and nutritional medicine for weight - loss diets.

1. ## Investigating how different concentrations of a antibiotic effects the growth of a bacterium.

results can be tested to make sure that they are correct difference rather then chance or mistake. In the t-test the two different results that will be gathered to see significance is the two concentrations 0.1 and 0.0001, so that it can be shown that these have no significance.

2. ## DETERMINING THE WATER POTENTIAL OF A POTATO TUBER CELLS USING THE WEIGHING METHOD.

to a low pressure system (vacuum). * Its height (gravitational potential): water will flow downhill. * Its charge (electrical potential): water is uncharged, so we can ignore this. FIGURE 2 WATER WILL FLOW SPONTANEOUSLY FROM A HIGH POTENTIAL TO A LOW POTENTIAL, LIKE A BALL ROLLING DOWN A HILL.2 PLASMOLYSIS: Plasmolysis is simply the shrinkage or

1. ## The investigation to find the effect of glucose concentration on fermentation of yeast.

All of the enzymes are form of protein and protein molecules are amino acids. Therefore as the temperature increases the rate of reaction also increase. The rate of reaction could be calculated by timing the time taken for a color change to take place.

2. ## To investigate one of the factors that affects the permeability of cell membranes.

When making measurements using the colorimeter, I made them to ?1%, because that was all the equipment would allow. Results: Concentration of alcohol (%) Light transmitted through solution (%) Average light transmitted (%) 1 2 3 0.00 56 56 61 57.67 20.00 60 53 55 56.00 40.00 48 58 49

1. ## An experiment measuring the potential difference generated by various simple electrochemical cell

Disconnect the voltmeter. 6.Repeat these steps for the other 2 cells. Results: Cell Positive electrode Negative electrode Potential difference (1) Cu2+ (aq) + 2e- ? Cu(s) Zn2+ (aq) + 2e- ? Zn (s) + 1.06 V (2) Ag+ (aq) +e- ?

2. ## Experiment Aim: To investigate the effects of placing onion epidermal cells in different solutions.

The measurements were tabulated. Observation: Table showing the A & B dimensions of five onion cells in both 0.6 moldm-3 and 1.0 moldm-3 solution of sucrose and extent of plasmolysis. Cell Number 1.0mmoldm-3 sucrose solution 0.6 moldm-3 sucrose solution Dimension A[mm] Dimension B[mm] C[mm] Dimension A[mm] Dimension B[mm] C[mm] 1

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