1. Surface Area Diffusion and Osmosis

transcript

Monday 10 April 2023

Surface Area, Diffusion and Osmosis

Welcome back!

Tasks:

1.Holiday homework due on Thursday:1. All Quick Check and Review Qu’s from ch1

IN THE BACK OF YOUR BOOK OR ON PAPER

2. Microscope Practical Write-Up (“Exploring one of the....” from booklet

2.You could begin Ch2 qu’s at home if you want. Due in 3 weeks.

Surface Area, Diffusion and Osmosis

From p31

Surface Area to Volume Ratio

Make 3 cubes from Plastecine:

1x1x1 2x2x2 3x3x3

Cube dimensions

Surface Area / cm2 Volume / cm3

Surface Area to Volume

Ratio (SA/V)

1x1x1 6 1 6

2x2x2 24 8 3

3x3x3 54 27 2

As the volume of the cubes increases, then...

• What does this mean in reality?

• The bigger the object becomes, the less surface area there is available per unit volume

• Complete:– Limitation to cell size: surface area to volume

ratio– From your booklet

Diffusion and Osmosis

• Recap your concept of particles:

• Draw Solid, Liquid and Gas

• Link

• Diffusion

Evaporation of some particles

(not necessarily at BP)

• Diffusion

As time passes, the particles spread = diffusion

• Diffusion

There is a concentration gradient: particles have moved from an area of high concentration to low concentration

• Diffusion• Link 2

Diffusion = the spreading of particles (liquid or gas) from an area of higher concentration to an area of lower concentration

• Osmosis: diffusion of water in a cell

Cell Membrane

Higher

concentration of water

• Osmosis: diffusion of water in a cell

Cell Membrane

concentration of salt

Higher

concentration of salt

Conc of water

Osmosis = the spreading of water particles from an area of higher water concentration to an area of lower water concentration, or down the concentration gradient

Link 3

Diffusion and Equilibrium

Key Words

• Hypotonic Solution:– Contains more water and less solute (than

another solution)

• Hypertonic Solution– Contains less water and more solute (than

another solution)

• Isotonic Solution– Contains equal concentration of solute (to

another solution)

Osmosis and Equilibrium

Osmosis and Equilibrium in Cells

Answer these questions:

• Read p27-8– Write a definition for these terms:

• Diffusion• Osmosis• Hydrophilic• Lipophilic• Facilitated Diffusion

– Explain what happens to a cell if you put it into

• a Hypertonic Solution• A Hypotonic Solution

1. Surface Area Diffusion and Osmosis

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