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Open the SIN Y11 Transition Site- biology

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04 Movement in and out of cells

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Here’s the study sheet

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Yr11 KS4/5 Online Transition Sessions 2021

Biology

Session 04 - Friday 25 June

Movement in and out of cells

Try this

Diffusion

Movement of a molecule from an area of high concentration to an area of low concentration

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Which factors affect the rate of diffusion...and why?

Diffusion

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And why?

Osmosis

Movement of water from an area of high concentration to an area of low concentration across a partially permeable membrane

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Active transport

The movement of a molecule against its concentration gradient…

...using the energy from respiration

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Let’s step up

First, we need to know about membranes

Try this

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See how much you can answer with GCSE knowledge!

Diffusion

Lipid soluble molecules dissolve in the lipid bilayer

They diffuse down their concentration gradient, in and out of the cell

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Slightly polar molecules, such as water, and some slightly larger molecules diffuse through water filled, hydrophilic channels in channel proteins

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These channels are specific to a single type of molecule

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Try this

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Active transport

It is specific

It can move molecules and ions against the concentration gradient

Requires energy in the form of ATP

Binding of ATP to carrier protein changes conformation of protein

Molecule is transported across membrane

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All about water potential

Water potential is the pressure exerted by the water molecules

It is the potential ‘to do dissolving’

It is measured in kPa, unit ψ

Pure water has the value 0kPa

As a solute is dissolved in the solvent the solution becomes more negative

The more negative the solution becomes, the less it can dissolve

Eventually it becomes a saturated solution

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Your turn

Water moves from where it is zero or negative to where it is negative down its concentration gradient

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Which way will it move?

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LOs set up and use artificial cells to investigate osmosis

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