ks4-movement-in-and-out-of-cells.ppt

8/18/2019 KS4-Movement-In-and-Out-of-Cells.ppt

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© Boardworks Ltd 20041 of 44

KS4 Biology

MovementIn and Out of ells


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Osmosis

!"#eriments$ diffusion and osmosis

Movement In and Out of ells

%iffusion and life #ro&esses '&tive trans#ort

ontents

()at is diffusion*

Multi#le+&)oi&e ,ui-


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Why does the colour ofconcentrated fruit drink change

when it is added to water?

Why can you smell cooked

food from a distance?

Smells and li,uids s#reading out

Why can you smellperfume or aftershave

when someone walks

past you?


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These processes are all examples of diffusion.

Smelling cooked food or perfume and diluting juice in water

all involve things moving around and s#reading out.

Smells and li,uids s#reading out

Diffusion involves the movement of mole&ules.

What type of molecules are moving in these examples?


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The molecules in every substance are always moving.

Moving mole&ules

n which state are molecules able to spread out?

water li,uid water va#our gas

%iffusion involves the movement of gas and dissolved

mole&ules. Why don!t solid molecules diffuse?

i&e solid


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When smelling body spray where is the smell strongest

and where is the smell weakest?

%iffusion and &)anging &on&entrations

Smell is strongest

at sour&e3

%iffusion means t)e smell

s#reads out and gets weaker

furt)er away from t)e sour&e3

"ow does the concentration of smell molecules changeduring diffusion?

Smell molecules move from an area of high concentration

to an area of lower concentration. This is called a

&on&entration gradient.


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Where will the molecules be after diffusion?

%iffusion can be represented on a simple diagram.

)anging &on&entrations

5efore diffusion

Diffusion is the movement of gas or dissolved moleculesfrom )ig)er to lower &on&entration.

#olecules diffuse down a concentration gradient.

What does this mean?

after diffusion

What has happened to the concentration of the molecules?


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%iffusion animation 1


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%iffusion animation 2


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%iffusion animation .


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Osmosis!"#eriments$ diffusion and osmosis


%iffusion and life #ro&esses '&tive trans#ort

ontents

()at is diffusion*




()y is diffusion so im#ortant*

Diffusion occurs in the organ systems that control your5reat)ing8 &ir&ulation8 digestion and other life

processes.

Diffusion explains why you can smell smelly smells and

what happens when you dilute a concentrated fruit drink.

More im#ortantly8 diffusion is an essential #ro&ess

t)at is going on inside your 5ody rig)t now and

kee#ing you alive9


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Diffusion is the movement of gas or dissolved molecules.

What gas and dissolvedmole&ules do body cells need?

$our body!s survival depends

on o"ygen and dissolved food

mole&ules getting into your cells.

%iffusion and life #ro&esses

"ow do these vital substances cross boundaries

within the body to get to where they are needed?

%xygen and dissolved food moleculesmust diffuse into and out of the blood

for transportation around the body.

Where does diffusion take place within the body?



&reathing involves the exchange of

gases in the lungs' a process which

occurs by diffusion.

What is the vital gas that

you 5reat)e in?

%iffusion and 5reat)ing

The lungs have a )uge surfa&e area to maximi(e the

exchange of oxygen and carbon dioxide with each breath.

Where in the lungs does gas exchange take place?

o"ygen

&ar5on dio"ide

What is the waste gas that

you 5reat)e out?


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)as exchange takes place in the alveoli' the tiny air sacs

at the end of the bronchioles.

%iffusion and 5reat)ing

What are these blood vessels around each alveolus called?



nhaling in&reases the concentration of oxygen molecules

in an alveolus.

*t this point' how does this compare with the concentration

of oxygen in deoxygenated blood in the capillary?

%iffusion and 5reat)ing : o"ygen

deoxygenated blood

from the body

oxygenated blood

to the body

When you inhale'the concentration

of oxygen inside

ea&) alveolus is

)ig)er than in

deoxygenatedblood.

oxygen

into alveoli



"ow is the concentration of oxygen in the blood increased?

%xygen molecules diffuse across the lining of the alveolusinto the blood in the capillary' moving from higher to lower

concentration.

%iffusion and 5reat)ing : o"ygen

oxygenated blood

to the body

deoxygenated blood

from the body

oxygen

into alveoli

diffusion

When you inhale'the concentration

of oxygen inside

ea&) alveolus is

)ig)er than in

deoxygenatedblood.



Deoxygenated blood from the body is low in oxygen

but has high levels of carbon dioxide.

"ow does this compare with concentration of carbon dioxide

in the alveolus?

%iffusion and 5reat)ing : &ar5on dio"ide

deoxygenated blood

from the body

oxygenated blood

to the body

The concentrationof carbon dioxide

in deoxygenated

blood is )ig)er

than indeoxygenated

blood.



"ow is the concentration of carbon dioxide in the blood

reduced?

+arbon dioxide molecules diffuse from the blood in the

capillary into the alveolus' moving from higher to lower

concentration.

%iffusion and 5reat)ing : &ar5on dio"ide

deoxygenated blood

from the body

oxygenated blood

to the body

The concentrationof carbon dioxide

in deoxygenated

blood is )ig)er

than indeoxygenated

blood.

carbon dioxide

out of alveoli

diffusion



;as e"&)ange animation



%iffusion and digestion

Digestion breaks large food

molecules into smaller molecules

that can be used by the body.

Dissolved food molecules

then need to be transported

from the small intestine into

the bloodstream.

Where in the small intestine does

this diffusion take place?

+arbohydrates' proteins and fat are made up of large

molecules that cannot be used directly by the body.

I id ) ll i i



Inside t)e small intestine

ti f ill


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ross+se&tion of a villus

,ach villus separates the digested food in the small intestine

from a network of capillaries.

%iff i f t) ll i t ti



%iffusion from t)e small intestine

,ach villus has a surface layer that is one cell thick.

"ow does the concentration of dissolved food molecules inthe small intestine compare with the blood entering a villus?

The concentration of

dissolved food molecules

is )ig)er in the small

intestine than in the

blood entering the villus.

wall of small

intestine

blood entering

villusblood leaving

villus

inside the

small intestine

%iff i f t) ll i t ti


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%iffusion from t)e small intestine

Dissolved food molecules diffuse from the small intestine

into the blood' moving from higher to lower concentration.

"ow is the concentration of dissolved food molecules in the

blood increased?


dissolved food molecules

is )ig)er in the small

intestine than in the

blood entering the villus.

wall of small

intestine

blood entering

villusblood leaving

villus

inside the

small intestine

diffusion

%iff i i d t f ll



%iffusion in and out of &ells

%xygen and dissolved food molecules are transported to

the body!s cells in the bloodstream.

"ow does the concentration of these useful substances in

the blood compare with the concentration inside the cells?


oxygen and dissolved

food molecules

is )ig)er in the blood

arriving at the cells

than inside the cells.

%iff i i d t f ll




"ow do oxygen and dissolved food molecules pass

from the blood into the cells?

%xygen and dissolved food molecules diffuse into the

body cells' moving from higher to lower concentration.


oxygen and dissolved

food molecules

is )ig)er in the blood

arriving at the cells

than inside the cells.

What process involving

these useful substances

takes place inside the cell?

diffusion

%iff i i d t f ll




The cells use the food and oxygen for res#iration.

ar5on dio"ide is the waste product of respiration andwill poison a cell if it is not removed. "ow is it removed?

+arbon dioxide molecules

diffuse from the cells intothe bloodstream' moving

from higher to lower

concentration.

"ow is this waste carbondioxide removed from the

body?

diffusion

t t



Osmosis




'&tive trans#ort

ontents

()at is diffusion*


()at is a&tive trans#ort*


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()at is a&tive trans#ort*

#ovement of substances in and out of cells by diffusion

involves molecules moving down a concentration gradient

from high to low concentration.

Sometimes substances move into cells from low to high

concentration. This is called a&tive trans#ort.

*ctive transport needs energy to make it happen.

"ow do molecules move along the concentration gradient

during active transport?

)ig) &on&entration

low &on&entration

diffusion a&tive trans#ort

'&tive trans#ort and #lants


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-lants need mineral elements from the soil for healthy

growth. #inerals enter a plant though its roots.

The concentration of minerals in the soil is lower than that

inside a root hair cell' so how do minerals enter the root cell?

soil

mineralelement

root )air

&ell



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#inerals enter a root cell by a&tive trans#ort.

The plant uses energy to move minerals u# theconcentration gradient from the soil into its root cells.

Why is it important for plants to use energy in this way?

soil

mineralelement

root )air

&ell

a&tive trans#ort

ontents


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()at is osmosis*

Osmosis is a special type of diffusion.

Diffusion involves gas or dissolved molecules' but osmosis

only involves t)e movement of water mole&ules.

%smosis occurs across a semi#ermea5le mem5rane which has tiny )oles in it.

These holes are small enough for water molecules to pass

water

mole&ule

through but larger molecules cannot pass through.

()at )a##ens during osmosis*


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()at )a##ens during osmosis*

%smosis is the movement of water molecules from a

region of )ig) water &on&entration to a region of low

water &on&entration across a semipermeable membrane.

%smosis is a type of diffusion' so what do you think

happens to water molecules during this process?

water

mole&ule

semi#ermea5le mem5rane

osmosis

Osmosis e"#eriment


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Osmosis e"#eriment

* bag made from a semi#ermea5le mem5rane is tied

to a glass tube and filled with a strong sugar solution.

What happens to the water molecules in the weak solution?

What happens to the liuid inside the semipermeable bag?

This bag is placed in a weak sugar solution.

strong sugar

solution

weak sugar

solution

Osmosis e"#eriment


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strong sugar

solution

weak sugar

solution

Osmosis e"#eriment

Water molecules diffuse across the membrane from the

weak sugar solution into the strong sugar solution.

This continues until the concentration is the same on both

The volume of liuid in the semipermeable bag increases.

The liuid rises up the glass tube and then stops.

Why does this happen?

sides of the membrane.

Osmosis animation 1


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Osmosis animation 1

Osmosis animation 2


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Osmosis animation 2

ontents


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Osmosis




'&tive trans#ort

ontents

()at is diffusion*


!"#eriment to demonstrate diffusion


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!"#eriment to demonstrate diffusion

!"#eriment to investigate osmosis


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!"#eriment to investigate osmosis

ontents


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Osmosis




'&tive trans#ort

ontents

()at is diffusion*




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ks4-movement-in-and-out-of-cells.ppt

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