Passive Transport Passive Transport NotesNotes

TransportTransport Passive TransportPassive Transport – movement of – movement of

substances down their concentration substances down their concentration gradient (high concentration to low gradient (high concentration to low concentration); no energy required.concentration); no energy required.

Passive TransportPassive Transport 4 types of passive transports4 types of passive transports:: 1. Diffusion1. Diffusion 2. Osmosis2. Osmosis 3. Facilitated Diffusion3. Facilitated Diffusion 4. Diffusion through Ion Channels4. Diffusion through Ion Channels

DiffusionDiffusion DiffusionDiffusion – is the – is the

movement of movement of molecules from an molecules from an area of high area of high concentration to an concentration to an area of lower area of lower concentration.concentration.

EquilibriumEquilibrium EquilibriumEquilibrium – is the state when the – is the state when the

concentration of molecules are equal on concentration of molecules are equal on both sides of the membrane.both sides of the membrane.

OsmosisOsmosis OsmosisOsmosis – is the – is the

process of process of waterwater diffusing across a diffusing across a cell membrane from cell membrane from an area of high an area of high concentration to an concentration to an area of lower area of lower concentration.concentration.

OsmosisOsmosis Water moves down its concentration Water moves down its concentration

gradient and does not require energy, so gradient and does not require energy, so it is a type of passive transport.it is a type of passive transport.

Passive TransportsPassive Transports To fully understand how diffusion and To fully understand how diffusion and

osmosis works in a cell, you need to osmosis works in a cell, you need to know a few vocabulary words that you know a few vocabulary words that you should have learned last year.should have learned last year.

SolutionsSolutions

What is a solution?What is a solution? SolutionSolution – is a – is a

mixture in which one mixture in which one or more substances or more substances are equally distributed are equally distributed in another substance.in another substance.

Ex. Pop, saltwater, Ex. Pop, saltwater, sugarwatersugarwater

Parts of Parts of SolutionSolution

2 parts of a solution2 parts of a solution:: 1. Solute1. Solute – is the – is the

substance being substance being dissolved by the solvent.dissolved by the solvent.

Ex. Salt or sugarEx. Salt or sugar 2. Solvent2. Solvent – is the – is the

substance that dissolves substance that dissolves the solutethe solute

Ex. Water Ex. Water

MixturesMixtures Solutions can be made of various Solutions can be made of various

proportions of solutes and solvents.proportions of solutes and solvents.

ConcentrationConcentration – the amount of solute – the amount of solute dissolved in a fixed amount of solution.dissolved in a fixed amount of solution. Ex: 1g. of salt in 10g. of water= 10% salt solutionEx: 1g. of salt in 10g. of water= 10% salt solution

Saturated SolutionSaturated Solution – is when no more – is when no more solute can be dissolved. The solute just lays solute can be dissolved. The solute just lays at the bottom of the cup.at the bottom of the cup.

Passive TransportsPassive Transports A big part of understanding homeostasis A big part of understanding homeostasis

(body is at equilibrium), is understanding (body is at equilibrium), is understanding how a cell will react in different solutions.how a cell will react in different solutions.

So, we have special names for solutions So, we have special names for solutions in how they affect cells.in how they affect cells.

Types of SolutionsTypes of Solutions HypotonicHypotonic – when – when

the concentration of the concentration of solutes outside the solutes outside the cell is lower than the cell is lower than the concentration of concentration of solutes inside the solutes inside the cell.cell.

Ex. Cells in a beaker Ex. Cells in a beaker of pure water.of pure water.

Types of SolutionsTypes of Solutions In a hypotonic solution the water in the In a hypotonic solution the water in the

solution would move into the cell to reach solution would move into the cell to reach equilibrium.equilibrium.

This could cause the cell to burst and is This could cause the cell to burst and is why your hands get wrinkly when bathing why your hands get wrinkly when bathing for a long time.for a long time.

Types of SolutionsTypes of Solutions HypertonicHypertonic – when – when

the concentration of the concentration of solute outside the solute outside the cell is higher than the cell is higher than the concentration inside concentration inside the cell.the cell.

Ex. A cell in a beaker Ex. A cell in a beaker of saltwater.of saltwater.

Types of SolutionsTypes of Solutions The water will move out of the cell and The water will move out of the cell and

into the solution to reach equilibrium.into the solution to reach equilibrium. This may cause the cell to shrivel up and This may cause the cell to shrivel up and

become dehydrated.become dehydrated.

Types of SolutionsTypes of Solutions IsotonicIsotonic – when the – when the

concentration of solutes concentration of solutes outside and inside the outside and inside the cell are equal.cell are equal.

Same amount of salt Same amount of salt outside and inside the outside and inside the cell.cell.

This is the goal of every This is the goal of every cell.cell.

Water will move both Water will move both ways.ways.

VocabularyVocabulary Turgor PressureTurgor Pressure - is the pressure inside - is the pressure inside

the cells that give organisms there form.the cells that give organisms there form.

Organisms without turgor pressure will Organisms without turgor pressure will have no form out of water.have no form out of water.

Cells loose turgor pressure when they Cells loose turgor pressure when they loose water.loose water.

Turgor PressureTurgor Pressure This is why plants wilt in the summer, This is why plants wilt in the summer,

because they have lost water due to dry because they have lost water due to dry weather.weather.

The water evaporates out of the vacuole The water evaporates out of the vacuole (storage in plant cells) and with no water (storage in plant cells) and with no water there is no turgor pressure.there is no turgor pressure.

Facilitated DiffusionFacilitated Diffusion Facilitated DiffusionFacilitated Diffusion

– is the movement of – is the movement of molecules through molecules through the membrane by the membrane by using proteins.using proteins.

Carrier ProteinsCarrier Proteins – – are the proteins used are the proteins used in facilitated in facilitated diffusion.diffusion.

Diffusion Diffusion ThroughThrough Ion Ion ChannelChannel

Is the process of transporting ions Is the process of transporting ions through membrane proteins known as ion through membrane proteins known as ion channels.channels.

Ex. ions are Sodium, potassium, calcium, Ex. ions are Sodium, potassium, calcium, and chloride.and chloride.

These ions use the proteins as a channel These ions use the proteins as a channel to move through the membrane and into to move through the membrane and into the cell.the cell.

Ion ChannelsIon Channels Each type of ion Each type of ion

channel is usually channel is usually specific for one type specific for one type of ion.of ion.

Most channels allow Most channels allow Na to pass through.Na to pass through.

Passive Transport Passive Transport Question????Question????

If you put a piece of potato into a beaker of distilled water and another piece of potato in a beaker of saltwater. The piece of potato in the freshwater becomes very stiff, while the piece of potato in the saltwater became very flexible.

In complete sentences explain why the potato in the freshwater became stiff and the potato in the salt water became flexible. (4 points)

Answer to Passive Answer to Passive Transport QuestionTransport Question

The piece of potato that was put into distilled water The piece of potato that was put into distilled water swelled up and stiffened, because of an increase in swelled up and stiffened, because of an increase in turgor pressure. The turgor pressure increased turgor pressure. The turgor pressure increased because the potato was in a hypotonic solution which because the potato was in a hypotonic solution which caused water to move into the potato by a process caused water to move into the potato by a process called osmosis. The piece of potato that was put into called osmosis. The piece of potato that was put into the saltwater shrank and became flexible, because of a the saltwater shrank and became flexible, because of a loss of turgor pressure. The turgor pressure was lost, loss of turgor pressure. The turgor pressure was lost, because the potato was in a hypertonic solution which because the potato was in a hypertonic solution which caused water to move out of the potato by a process caused water to move out of the potato by a process called osmosis.called osmosis.