• 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
3. 3
3
4. 4
4
5. 5
5
6. 6
6
7. 7
7
8. 8
8
9. 9
9
10. 10
10
11. 11
11

# Osmosis - how does the concentration of water affect the mass of a potato?

Extracts from this document...

Introduction

Biology Coursework Osmosis- how does the concentration of water affect the mass of a potato? Abubakar Hatimy Aim: - My aim is to find the percentage change of mass when a small piece of potato is placed in to molar sucrose solution Apparatus: o Molar sucrose solution 0.0 - 0.5 o Potato o Cutting board o Knife o Weighing machine o Glass test tube o Glass test tube holder Plan: - My plan is too find the percentage change of mass of a small piece of potato when placed in to molar sucrose solution by using osmosis. Osmosis is explained below Osmosis Osmosis is the passage of water molecules from a region of their high concentration to a region of their low concentration through a partially permeable membrane. It is best regarded as a form of diffusion in which only water molecules move. For example look at Figure 2. The solute molecules are too large to pass through the pores in the membrane, so the movement of water molecules can only achieve equilibrium. Solution A has the higher concentration of water; so there will be a net movement of water from A to B by osmosis. At equilibrium there will be no further net movement of water. The tendency of water molecules to move from one place to another is measured as the water potential, represented by the symbol ?????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? ...read more.

Middle

is ?s. for a solution, ? = ?s. Pressure potential, ?p If pressure is applied to pure water or a solution, it water potential increases. This is because the pressure is tending to force the water from one place to another. Such a situation may occur in living cells. For example, when water enters plant cells by osmosis, pressure may build up inside the cell making the cell turgid and increasing the pressure potential. Also, water potential of blood plasma is raised to a positive value by the high blood pressure in the glomerulus of the kidney. Pressure potential is usually positive, but in certain circumstances, as in xylem when water is under tension (negative pressure) it may be negative. Summary Water potential is affected by both solute potential and pressure potential, and the following equation summarises the relation between the two terms. ? = ?s + ?p Water Solute Pressure Potential Potential Potential Solute potential is negative and pressure potential is usually positive. Osmosis and plant cells The partially permeable membranes of importance in the water elations of plant cells are shown in figure 1. The cell wall is usually is freely permeable to substances in solution, so its not important in osmosis. The cell contains a large central vacuole contents, the cell sap, contribute to the solute potential of the cell. ...read more.

Conclusion

Firstly, I could have made the project better by doing more experiments so that the average results would be more accurate. I only did two experiments so the experiment was accurate by it self but the whole project was not a fair experiment. I could have probably done three more experiments to be accurate. Secondly, what I could have also done to make my experiment better is that I could have timed the small pieces of potato so that they were in the solution the same time and the osmosis processing time will be the same and the potatoes would have a fair experiment., I reckon that this was one of the reasons that the experiment was not so accurate. Thirdly, I should have cut the pieces of potato as the same weight for all. This would have made the experiment simpler to understand and this would have become more accurate experiment. The osmosis process would have worked equally because they all had the same mass, therefore the experiment would be more accurate. 1 Technically ? means potential and water should be presented ?w. Since in living systems the solvent we are concerned with is always water, it is simpler to use ? and assume the w. 2 Pressure was formerly measure in atmospheres (atm), but now Pascal is used (Pa). 1 Pa = 1NM-2 (N = Newton) Abubakar Hatimy Biology Coursework-Osmosis. Page 1 ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Green Plants as Organisms 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

# Related GCSE Green Plants as Organisms essays

1. ## Osmosis in potato and apple

3 star(s)

The hypothesis is that there is a different in water potential between apple and potato tissue. I have done some background research on osmosis and related topics. The sources of the research are: 'A-level Biology' (page 214) by W.D. Phillips And T.J.

2. ## Determine the water potential of potato tuber cell with the varying affect of solute ...

Protoplast peeled away Concentrated solution The reason why we use a potato cylinder is because it is made up of plant cells plus the fact that it has a partially permeable membrane. So to be able to determine the water potential it is essential to know the structure of the plant cell membrane.

1. ## What effect does the sucrose concentration have on osmosis?

the hydrostatic pressure produced by a solution in a space divided by a differentially permeable membrane due to a differential in the concentration of solute. Hypothesis I predict that when there is a strong concentration of sucrose the water molecules from within the potato piece will leave the potato

2. ## Sensor Project

Prediction As the polystyrene is lifted by the water, the arm will turn the potentiometer increasing its resistance and causing the voltage across it to decrease. The amount is uncertain but it should show a strong relation between the amounts of water.

1. ## Biology Coursework

At the measurement of 20 cm the colour of the ph was black/green for readings 2and 3 because the height of the lamp had been increased causing some of the light energy to slow down because the distance the light had to travel is longer causing particles in the air

2. ## The aim of the investigation is to find the exact concentration of the cell ...

but we are interested in the concentration of the cell sap to do this I will change the molarity of the solution from 1M to 0 (180g dissolves in 1 litre of water to make 1M solution). Then when we have a result when there is no percentage change we

1. ## The location of panama

It would also affect the world economy by forcing ships lengthen their journey by 8,000 miles. Fresh drinking water loss, which only comes from Lake Gatun, is another major issue for more than 700,000 people who live in Panama City.

2. ## Osmosis investigation. My prediction is that as the concentration of the solute increases, ...

To make my solutions of 0, 0.25, 0.5, 0.75 and 1 mole sucrose, I will use ratios- e.g. for 0.5: 1:1, so 10ml of each. Next I will prepare the potato pieces for their "soak". 2. I will aim to attain all the pieces from one potato.

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