3.2 Movement of Substances Across the Plasma Membrane in Eve

3.2 3.2 Movement of Substances Movement of Substances

across the Plasma across the Plasma Membrane in Membrane in Everyday LifeEveryday Life

Types of solutionTypes of solution

Three types of solution:Three types of solution:

1.1. HypotonicHypotonic

2.2. HypertonicHypertonic

3.3. Isotonic Isotonic

1.1. HypotonicHypotonic solution – the concentration solution – the concentration of solute of solute outsideoutside a cell is a cell is lowerlower thanthan the concentration of solute the concentration of solute insideinside of the of the cell (Hypo – lower)cell (Hypo – lower)

2.2. HypertonicHypertonic solution – the concentration solution – the concentration of solute of solute outsideoutside the cell is the cell is higherhigher thanthan the concentration of solute the concentration of solute insideinside of the of the cell (Hyper – higher)cell (Hyper – higher)

3.3. IsotonicIsotonic solution – the concentration of solution – the concentration of solute solute outsideoutside the cell is the cell is equalequal withwith the the concentration of solute concentration of solute insideinside of the of the cell (Iso – equal)cell (Iso – equal)

Effect of hypotonic, Effect of hypotonic, hypertonic and isotonic hypertonic and isotonic solution on animal cellssolution on animal cells

Red blood cell is put in aRed blood cell is put in a hypotonichypotonic solution solution – water from the surrounding enters the cell – water from the surrounding enters the cell by osmosis causing it to by osmosis causing it to swell up and burst swell up and burst (haemolysis – the bursting of red blood cell) (haemolysis – the bursting of red blood cell)

Red blood cell is put in aRed blood cell is put in a hypertonichypertonic solution solution – water from inside the cell move out of the – water from inside the cell move out of the cell by osmosis causing the cell to cell by osmosis causing the cell to shrink shrink (crenation – the shrinking of the cell)(crenation – the shrinking of the cell)

Red blood cell is put in an Red blood cell is put in an isotonicisotonic solution – solution – no changeno change to the cell because the amount of to the cell because the amount of water entering and leaving the cell is the water entering and leaving the cell is the samesame

Summarisation

Effect of hypotonic, Effect of hypotonic, hypertonic and isotonic hypertonic and isotonic solution on plant cellssolution on plant cells

A plant cell place in aA plant cell place in a hypotonic solutionhypotonic solution – – cell cell swell swell and become and become turgidturgid but does not but does not burst because the cell wall resist the burst because the cell wall resist the pressure (turgor pressure) stop the cell from pressure (turgor pressure) stop the cell from expanding, the cell wall stretch but does not expanding, the cell wall stretch but does not break break A plant cell place in aA plant cell place in a hypertonic solutionhypertonic solution – – cell cell shrink shrink and and flaccid (plasmolysis – the flaccid (plasmolysis – the shrinking of the cell, opposite process - shrinking of the cell, opposite process - deplasmolysis )deplasmolysis )A cell place in anA cell place in an isotonic solutionisotonic solution – – no no changechange because the amount of water because the amount of water entering and leaving the cell is equalentering and leaving the cell is equal

Summarisation

The Effects and Application The Effects and Application of Osmosis in Everyday Lifeof Osmosis in Everyday Life

Group discussionGroup discussion

Discuss how osmosis occur inDiscuss how osmosis occur in

1.1. Wilting plantWilting plant

2.2. Food preservationFood preservation

Cells in living organism have to maintain their Cells in living organism have to maintain their osmotic balance so that they will not burst or osmotic balance so that they will not burst or crenate (interstitial fluid has the same crenate (interstitial fluid has the same concentration as the cytoplasmic fluid)concentration as the cytoplasmic fluid)

Wilting plantWilting plant – happens when too much – happens when too much fertilizer is added to the soil or water fertilizer is added to the soil or water shortage in soil. shortage in soil.

Food preservationFood preservation – adding salt or sugar to – adding salt or sugar to the preserve food will cause hypertonic the preserve food will cause hypertonic environment to the decomposers and they environment to the decomposers and they will die due to losing water to the surrounding will die due to losing water to the surrounding solutionsolution

3.3 Appreciating the 3.3 Appreciating the Movement of Substances Movement of Substances

across the Plasma across the Plasma MembraneMembrane

Movement of substances across the Movement of substances across the plasma membrane is very important plasma membrane is very important because:because:

1.1. To maintain a suitable pH and ionic To maintain a suitable pH and ionic concentration inside the cell for enzymatic concentration inside the cell for enzymatic activitiesactivities

2.2. To obtain food supplies for energy and raw To obtain food supplies for energy and raw materialsmaterials

3.3. To remove toxic substances or secrete To remove toxic substances or secrete useful substancesuseful substances

4.4. To generate ionic gradients essential for To generate ionic gradients essential for muscular and nervous activitiesmuscular and nervous activities

Test Yourself Test Yourself

1.1. What happen if an animal cells is put in a What happen if an animal cells is put in a hypotonic solution?hypotonic solution?

2.2. Why plant cells does not burst when Why plant cells does not burst when these cells is put in a hypertonic these cells is put in a hypertonic solution?solution?

3.3. Why is the movement of substances Why is the movement of substances across the plasma membrane is across the plasma membrane is important for the survival of living important for the survival of living organisms? organisms?

Thing that we’ve learned today:Thing that we’ve learned today:

The meaning of hypotonic, hypertonic and The meaning of hypotonic, hypertonic and isotonic solutions.isotonic solutions.

Effect of hypotonic, hypertonic and isotonic Effect of hypotonic, hypertonic and isotonic solution on animal cells. solution on animal cells.

Effect of hypotonic, hypertonic and isotonic Effect of hypotonic, hypertonic and isotonic solution on plant cells.solution on plant cells.

The Effects and Application of Osmosis in The Effects and Application of Osmosis in Everyday LifeEveryday Life

Appreciating the Movement of Substances Appreciating the Movement of Substances across the Plasma Membraneacross the Plasma Membrane