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Misconceptions of students

about osmosis

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OSMOSIS CONCEPT

Osmosis- Net movement of WATER MOLECULES(Solvent) from a solution of higher water concentration to a solution of lower water 

concentration.

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OSMOSIS CONCEPTS

Salts and sugars cannot get throughthe bilayer, but water can

This makes the cell membranesemipermeable.

The movement of water through asemipermeable membrane that blockssolutes from moving is called osmosis.

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Hypotonic means lower solute

concentrationo Animal cells can rupture in hypotonic

environmentso Plant cells are protected from rupture by their 

strong cell walls

Hypertonic means higher concentration of soluteso A cell placed in a hypertonic environment will

lose water and shrink.o Plant cells plasmolyze when placed in very

salty water.

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MISCONCEPTIONS OF

STUDENTS

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To know about misconceptions of students, they conducted a pre-test.

Then, they find out the misconception

of students. In the pre-test, they were asked to

state, describe and draw about

osmosis.

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Technique used: The student were asked tostate the correct term.

Question 1 :

State the term used to describe a

solution which has : Higher concentration relative to another solution -

 ___________________  A lower concentration relative to another solution -

 ___________________  The same concentration with another solution -

 ______________________ 

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Question 1 answer:

Higher concentration relative to another solution -HYPERTONIC

A lower concentration relative to another solution -HYPOTONIC

The same concentration with another solution ±

ISOTONIC

Result from pre-test :Based on this question :

7 students give wrong answer. 7 give right answer  5 did not answer this question.

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Question 4

Draw the plant cell which has been placed in asolution describe in question 1a,1b and 1c.

Plant in solutiondescribe in 1a

Plant in solutiondescribe in 1b

Plant in solution

describe in 1c

Technique used: The student were asked to draw.

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Scientific idea

The plant cell willundergoesplasmolysis in 4a

The plant cellwill becometurgid in 4b

The plant celldoes not changein shape in 4c

Results:

Student tends to show turgidity in question 4a

students showed plasmolysis in 4b

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Technique used: the student were asked todescribe

Question 5 Describe briefly what happen to a plant cell which

had been placed in a strong sucrose solution.

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Results:Answer  No of students Answer analysis The correct answer 

Plant cell undergoes simple diffusion to achieve equilibrium state of concentration gradient

1 Right

It will expand the and the density will be higher 1 Wrong The cell will plasmolyzed

The plasma membrane and vacuole of the plant cell will become bigger 1 Wrong The plasma membrane will pulled tothe center of the cell

Plant cell will be turgid 4 Wrong The plant cell will be plasmolized

Plant cell placed in strong sucrose solution have higher concentrationthan water solutions

2 Wrong Plant cell placed in sucrose solutionwill loss alot of water and becomehigh osmotic pressure in water solution

Plant cell bent to the right side because glucose in sucrose solutionabsorb into the plants

1 Wrong Glucose does not move into cell

The cell wall of plant cell will be destroyed 1 Wrong Cell wall cannot be destroyed whenplaced in sucrose solution

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Plant cell will wilt 1 Wrong Plant cell not wilt, butplasmolized

The plant cell diffuse the sucrose solution until itbecome turgid

1 Havescientificidea butwrong

Plant cell cannot diffusein sucrose solution

The strong sucrose solution will diffuse into plantcell and plant cell become much bigger than willexplode

1 Havescientificidea butwrong

Plant cell cannot explodebecause it has cell wall

Plant cell absorbs more water in a strong sucrosesolution causing cell sap to expand

1 Havescientificidea butwrong

Water will diffuse out tothe sucrose solution

The water diffuse into the plant cell and it will

expand and burst

2 Have

scientificidea butwrong

Water will diffuse out of 

the cell because thesucrose is low in water concentration.