Passive transport

1. Passive Transport

CIE Biology Jones
pp 79-85
(Not water potential)
G11 Biology 2017-2018
Learning Objective:
1. To explain the mechanism of passive transport
2. Calculate the ratio of the surface area to volume ratio and
explain their meaning with respect to transport substances.
Success Criteria
1. Describe types of passive transport in oral or written form.
2. Explain passive transport mechanism
3. Calculate the value of SA/V ratio and explain its value regarding substance movement.
4. Correctly calculate two animals SA/V ratio.
5. Make right conclusion on movement of two mentioned animals (ex high SA/V ratio of
amoeba says that oxygen can reach the center of amoeba, thus is does not require
elements of transportation system.

2. Terminology

Surface area to Volume SA:V
Ratio
Contents
Google Russian
Площадь поверхности до объема SA: V
соотношение
содержание
Passive transport
Concentration gradient
High to low – downhill
Equilibrium
Permeable, semipermeable, nonpermeable
Diffusion
- simple
- facilitative
- osmosis
Facilitative
channel
carrier protein
Пассивный транспорт
Градиент концентрации
Высокий - низкий - спуск
равновесный
Проницаемый, полупроницаемый,
непроницаемый
диффузия
- просто
- облегчение
- осмос
стимулированию
канал
белка-носителя
English

3. Surface Area to Volume SA:V

CIE Biology Jones
pp 79-85
(Not water potential)
G11 Biology 2017-2018
Learning Objective:
1. Calculate the ratio of the surface area to volume ratio and
explain their meaning with respect to transport substances.
Success Criteria
1. Calculate the value of SA/V ratio and explain its value regarding substance movement.
2. Correctly calculate two animals SA/V ratio.
3. Make right conclusion on movement of two mentioned animals (ex high SA/V ratio of
amoeba says that oxygen can reach the center of amoeba, thus is does not require
elements of transportation system.

4.

5.

6. Surface Area to Volume SA:V

Surface Area Video Practical - (10 min)
https://www.youtube.com/watch?v=CNkP4rycLbI

7.

8.

9.

10.

11.

12.

13.

14.

15.

Effect of increase in size
on surface area
For each of the ‘organisms’ above work out the surface area,
volume and then surface area to volume ratio. Q1 on handout.
SA=6
Vol=1
SA/V=6
SA=24
Vol= 8
SA/Vol=3
SA=96
Vol=64
SA/Vol=1.5
What is the consequence of this? Q2 on handout
The larger an organism, the more exchange has to take place to
meet the organism’s needs (larger volume) – but each unit of its
volume is supplied by a proportionally decreasing surface area.

16.

How can an organism increase in volume while still
managing to exchange enough nutrients by diffusion?
Answer questions 3 & 4 on handout.
D
SA= 34
V=8
SA:V= 4.25
E
SA=28
V= 8
SA:V=3.5
To obtain sufficient oxygen for the demands of the cells in the body
organisms need to greatly increase the surface area of the gas exchange
surface without significantly increasing volume.
Extension Question on handout:
Dessication/dehydration problems – surface also has a
protective function.

17.

18.

Wall of alveolus
alveoli
bronchiole

19. Summary: Why Surface Area to Volume is Important in Living Things.

- Substances need to be taken in to the cell to fuel reactions and waste products need to be
removed
- Increase in cell size leads to increase in chemical reactions more substances needed in
and more substances needing to be removed
- Surface area affects the rate at which particles enter and exit the cell
- Volume affects the rate of the chemical activities
- When the volume increases so does the surface area but not to the same extent
- As the cell gets larger, its surface area to volume ratio gets smaller
- If the ratio gets too small, particles will not be able to enter and exit the cell fast enough
- Results in accumulation of waste products and overheating of the cell

20. Passive Transport

CIE Biology Jones
pp 79-85
(Not water potential)
G11 Biology 20172018
Learning Objective:
1. To explain the mechanism of passive transport
2. Calculate the ratio of the surface area to volume ratio and
explain their meaning with respect to transport substances.
Success Criteria
1. Describe types of passive transport in oral or written form.
2. Explain passive transport mechanism
3. Calculate the value of SA/V ratio and explain its value regarding substance movement.
4. Correctly calculate two animals SA/V ratio.
5. Make right conclusion on movement of two mentioned animals (ex high SA/V ratio of
amoeba says that oxygen can reach the center of amoeba, thus is does not require
elements of transportation system.

21. Revise: Cell Membrane

• Cell membrane is semi- or selectively
permeable – not all molecules can pass
through.
Proteins
Lipid
Bilayer
Transport Proteins
Carbohydrates
Receptors

22. Two types of transport

23.

24. Diffusion

High
moves substance [high] to [low] .
•Uses the kinetic energy – from
movement, NO ATP energy.
Low

25.

High
Low

26. Passive transport uses a concentration gradient

• The difference in concentration of a given molecule
between two points is called the concentration
gradient.
High
• The larger the gradient, the greater the net
movement of the molecules.
• Molecules continue to move until equilibrium.
High to Low
Equilibrium
(gradient = 0)
Low

27. We will look at Passive Transport Only

Does not require energy (ATP).
Molecules move [high] to [low].
Three major types:
High
• Simple Diffusion
• Facilitated Diffusion
• Osmosis
Low

28.

High
Low
Passive Transport Movement of molecules
High
Low

29. Simple Diffusion across a Membrane

High
-small molecules may pass through the
semi- permeable membrane
Gases: N2, O2, CO2
Water: H2O
Water
(passes through the membrane, but will passes faster through an aquaporin, a channel
protein that specifically transports water through the membrane)
Low

30. Facilitated Diffusion

High
Molecules move
through proteins in
the membrane by the
concentration
gradient.
• [high] to [low]
• No ENERGY (ATP)
Low

31.

Facilitative Diffusion
-solute passes directly through
-no change of protein shape
-
solute binds to protein
protein changes shape
Solute passes through
High
Low

32. Osmosis

Involves Water moving
across a selectively
permeable membrane or
through through a
aquaporin.
• Very important in living
organisms.
High
Low

33. Look at the images and fill in the blank

Diffusion
Facilitated diffusion
Osmosis
Surface area

34. Respiration – Gas exchange Lung

1. CO2 and O2 gas exchange between the blood and
alveoli of the lungs is _______________ Alveoli are
clusters of small clusters of round, hollow, clusters that are a
single cell thickness in order to increase the cells
______________________.

35. Dialysis – removal of wastes from blood

2. Removal of small wastes by dialysis through
a semipermeable membrane wastes is
__________________________

36. Kidney Filtration

HO
3.
2 reabsorption is __________________
Filtration of NaCl / Urea / small molecules is ________

37. Plant Cells

4. Movement of H2O in a plant is _________.
Cells are small because it increases ___________.

38. Erythrocytes RBC

5. Movement of H2O in a RBC is _____________

39. Placental Exchange of Nutrients, Wastes, Gases

6. Exchange of small nutrient molecules, wastes and gases
would be ____________. Larger molecules like glucose would
be exchanged by a protein carrier – ___________________,
while water need by the fetus would be transported by
______________________.

40. Gas exchange in Fish

•Exchange of gases
through the
respiratory gills of fish
is ______________,
but it is driven
(powered) by the
movement of water_______________.
Gills of fish are flat and thin to increase
_____________________to increase the rate of the transfer
of ions and water, as well as the exchange of oxygen, carbon
dioxide, acids and
ammonia

41. Root hair cells

Absorb water and
minerals dissolved in
water through
______________ and
_______________
Root hairs are thin and
long to increase
___________________
for absorption.

42. Glucose Absorption

Glucose is a large molecule and must use a
_________________(carrier protein) to enter cell.

43. Absorption of Nutrients-Small Intestine

1. Digestion
Enzymes on lumen
wall of small intestine
digest disaccharides
into monosaccharide's.
2. Absorption
Monosaccharide's are
absorbed into cells of
the lumen of the small
intestine by
_________________
3. Absorption
Monosaccharide's
leave the intestine to
the bloodstream by
__________________
and enter the blood
for distribution
throughout the body.

44. Neural Transmission

________________ of neurotransmitter
molecules from vesicles toward the
neurotransmitter receptors, move from and area
of high concentration to low concentration.

45. Fill in the Blank Key

46. Respiration – Gas exchange Lung

1. CO2 and O2 gas exchange between the blood and
alveoli of the lungs is Diffusion. Alveoli are clusters of
small clusters of round, hollow, clusters that are a single cell
thickness in order to increase the cells surface area.

47. Dialysis – removal of wastes from blood

2. Removal of small wastes by dialysis through
a semipermeable membrane wastes is Diffusion

48. Kidney Filtration

HO
3.
2 reabsorption is Osmosis
Filtration of NaCl / Urea / small molecules is Diffusion

49. Plant Cells

4. Movement of H2O in a plant is Osmosis. Cells
are small because it increases surface area.

50. Erythrocytes RBC

5. Movement of H2O in a RBC is Osmosis

51. Placental Exchange of Nutrients, Wastes, Gases

6. Exchange of small nutrient molecules, wastes and gases
would be diffusion. Larger molecules like glucose would be
exchanged by a protein carrier – facilitated diffusion, while
water need by the fetus would be transported by osmosis.

52. Gas exchange in Fish

•Exchange of gases
through the
respiratory gills of fish
is diffusion, but it is
driven (powered) by
the movement of
water-osmosis.
Gills of fish are flat and thin to increase surface area to
increase the rate of the transfer of ions and water, as well as
the exchange of oxygen, carbon dioxide, acids and
ammonia

53. Root hair cells

Absorb water and
minerals dissolved in
water through diffusion
and osmosis
Root hairs are thin and
long to increase surface
area for absorption.

54. Glucose Absorption

Glucose is a large molecule and must use a
facilitated diffusion (carrier protein) to enter cell.

55. Absorption of Nutrients-Small Intestine

1. Digestion
Enzymes on lumen
wall of small intestine
digest disaccharides
into monosaccharide's.
2. Absorption
Monosaccharide's are
absorbed into cells of
the lumen of the small
intestine by facilitative
diffusion.
3. Absorption
Monosaccharide's
leave the intestine to
the bloodstream by
facilitated diffusion
and enter the blood
for distribution
throughout the body.

56. Neural Transmission

Diffusion of neurotransmitter molecules from
vesicles toward the neurotransmitter receptors,
move from and area of high concentration to
low concentration.

57. Video

Passive (1min) and active transport https://www.youtube.com/watch?v=kfy92hdaAH0
Membrane proteins https://www.youtube.com/watch?v=s0p1ztrbXPY
Volume of a cube https://www.youtube.com/watch?v=7BRVPOZhGfM

58. On back of paper make three columns

Diffusion
Osmosis
Facilitated Transport
1. Sort out different cards as to which type of transport they best
represent, a few cards may represent more than one type of transport.
2. Write a brief description of each form of transport represented.
3. Restack the cards and return to instructor.

59.

C - Cell
E- Environment
Match!
A. Drink large volumes of water
B. Doesn’t drink water
C-Hypertonic
E-Hypotonic water enters
C. Membrane permeable to water
1. Excrete large volumes of watery urine
C-Hypotonic
E-Hypertonic water exits
2. Gills pump excess salts out of body
3. Contractile vacuole pumps water out
Paramecium
C
E
Marine Sea Animal
Freshwater fish
C
E
C
E

60.

Cell shrinks –crenates
-cell dies
Water enters cell
Water enters cell
Cell membrane pulls away
from cell wall –plasmolysis
-cell dies
Water exits cell
Cell: hypertonic
Environment: hypotonic
Isotonic
Water exits cell
Cell: hypertonic
Environment: Hypotonic
Plant wilts
Cell: hypotonic
Environment: Hypotonic
Normal state
for animal cells
Cell: hypotonic
Environment: hypertonic
No net movement
of water.
Isotonic
No net movement
of water.
Match!