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Title: Diffusion and Osmosis concept notes
Description: These are my ppt slides for Diffusion and Osmosis (Movement of substance). I hope it helps you better understand the concept of Diffusion and Osmosis and the difference in gradients
Description: These are my ppt slides for Diffusion and Osmosis (Movement of substance). I hope it helps you better understand the concept of Diffusion and Osmosis and the difference in gradients
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CHAPTER 3
Movement of Substances
Chapter
3
Movement of Substances
3
...
2
Osmosis
3
...
4
Active Transport
3
...
3
...
Who will smell the popcorn first?
Who will smell the popcorn last? Why?
Region A has higher
concentration of particles
Region B has lower
concentration of particles
Movement of particles
3
...
Diffusion
Concentration gradient
Concentration gradient is the difference in
concentration between two regions
...
1
Point A
Point B
Distance
3
...
• Particles will diffuse down their concentration
gradient
...
• Think! Other than concentration gradient, what
other factors can affect the rate of diffusion?
3
...
A copper sulfate crystal is
dropped into a gas jar
containing water
...
The gas jar is allowed to
stand for a few days
...
The blue colour gradually
spreads throughout the water
...
The copper sulfate particles
diffused evenly throughout the
water
...
1
Diffusion
Diffusion across a membrane
• Both the solvent and solutes are able to pass
through a permeable membrane
...
1
Diffusion
Diffusion of gases in the lungs
Gaseous exchange in the lungs occurs via diffusion
...
1
Diffusion
3
...
3
Surface Area to Volume Ratio
3
...
2
Osmosis
Learning Outcomes
After this section, you should be able to:
• define osmosis; and
• discuss the effects of osmosis on plant and animal
tissues
...
2
Osmosis
What is osmosis?
Osmosis is the net movement of water
molecules from a solution of higher water
potential to a solution of lower water potential,
through a partially permeable membrane
...
2
Osmosis
What is osmosis?
A partially permeable membrane allows some
substances to pass through it but not others
...
2
Osmosis
What is osmosis?
The partially permeable membrane allows water
molecules to pass through but not sucrose molecules
...
2
Osmosis
How can we demonstrate osmosis?
1
...
2
...
3
...
thistle
funnel
retort
stand
sucrose
solution
cellophane
paper
beaker
water
3
...
• A dilute solution has a higher water potential
...
3
...
more solute,
lower water
potential
water potential
gradient established
partially
permeable
membrane
less solute,
higher water
potential
water moves down the gradient
3
...
Plant cell
Animal cell
partially permeable
cell surface
membrane
fully permeable
cellulose cell wall
enclosed nucleus and
cytoplasm containing
various dissolved
substances
3
...
2
Osmosis
What happens to a cell in a solution
with higher water potential?
cytoplasm has lower water
potential than outside solution,
water enters by osmosis
in solution of higher
water potential
animal cell
cell expands
and bursts
3
...
2
Osmosis
What happens to a cell in a solution
with lower water potential?
cytoplasm has higher
water potential than
surrounding solution,
water leaves by osmosis
in solution of lower
water potential
animal cell
URL
cell shrinks in size
and becomes
crenated
3
...
3
...
• It keeps herbaceous (non-woody) plants firm and
upright
...
3
...
g
...
turgor in guard cells
causes stoma to
open in the day
lack of turgor in guard
cells causes stoma to
close at night
3
...
• When cells of a plant become flaccid, the plant wilts
...
This causes water moelcules to enter the
plant cells and keeps the plant firm and upright
...
1
Diffusion
3
...
3
Surface Area to Volume Ratio
3
...
3
Surface Area to Volume Ratio
Learning Outcomes
After this section, you should be able to:
• explain how surface area to volume ratio affects
the rate of movement of substances
...
3
Surface Area to Volume Ratio
What does surface area to volume
ratio mean to a cell?
The greater the surface area to volume ratio, the
faster the rate of diffusion
...
3
Surface Area to Volume Ratio
What does surface area to volume
ratio mean to a cell?
Cube
Surface
area/cm2
Volume/c
m3
Surface area:
volume
Cell A1
(side 1 cm)
6
1
6:1
Cell A2
(side 2 cm)
24
8
3:1
Cell A3
(side 3 cm)
54
27
2:1
As a cell becomes bigger, its surface area to
volume ratio decreases
...
3
Surface Area to Volume Ratio
Each shaded square represents
a unit volume of protoplasm
food + O2 in
waste products out
Cell A2
Cell A1
Y
Cell A3
Z
X
loss in surface area
loss in surface area
3
...
• For example, root cells have long processes and
epithelial cells have a folded cell membrane
...
1
Diffusion
3
...
3
Surface Area to Volume Ratio
3
...
4
Active Transport
Learning Outcomes
After this section, you should be able to:
• define active transport;
• explain that active transport is an energyconsuming process by which substances are
transported against a concentration gradient; and
NOT IN COMBINED SCIENCE SYLLABUS
3
...
NOT IN COMBINED SCIENCE SYLLABUS
3
...
g
...
lower concentration
of solute molecules,
e
...
glucose
...
4
Active Transport
• Since active transport requires energy, active
transport occurs only in respiring living cells
...
root hair cell
path taken by substances
absorbed by root hair cell
soil solution
mineral salts
Title: Diffusion and Osmosis concept notes
Description: These are my ppt slides for Diffusion and Osmosis (Movement of substance). I hope it helps you better understand the concept of Diffusion and Osmosis and the difference in gradients
Description: These are my ppt slides for Diffusion and Osmosis (Movement of substance). I hope it helps you better understand the concept of Diffusion and Osmosis and the difference in gradients