TOPIC : MOVEMENT ACROSS THE PLASMA MEMBRANE
SUB TOPIC 3.1 : Analysing the movement of substances across the
plasma membrane
Learning outcomes (LO) : State the substances required by living
cells State the substances that have to be eliminated from cells
Explain the necessity for movement of substances across the plasma
membrane Describe the structure of the plasma membrane, Describe
the permeability of the plasma membrane Explain the movement of
soluble substances across the plasma membrane through the process
of passive transport, Explain the movement of water molecules
across the plasma membrane by osmosis Explain the movement of
substances across the plasma membrane through the process of active
transport . Explain the process of passive transport in living
organism using examples Explain the process of active transport in
living organism using examples. Compare and contrast passive
transport and active transport.
1. Substances
EliminatedRequired
Carbon dioxide Ammonium ions Water Amino acid Glycerol
Fatty acid Minerals Vitamin
(a) Fill in the blanks with the correct answer.
It is necessary for substances to move across the plasma
membrane to _________________ the concentration of ions, molecules
or substances inside and outside of the cell at ____________ level
for cells to continue their life processes.
2. Structure of plasma membraneName (N)Pore protein
Characteristic (C) Has a _____________ Embedded in phospholipid
bilayer
Function(F)To allow _________, water -soluble and charged
molecules to pass through the plasma membrane
Name (N)__________________
Characteristic (C) Has ____________ head and ______________
tails Arranged in two layers (bilayer)
Function(F)To allow small, uncharged and fat-soluble molecules
to pass through the plasma membrane
Name (N)Carrier protein
Characteristic (C) Has an ______________ Embedded in
phospholipids bilayer
Function(F)To allow big and _________________ molecules to pass
through the plasma membrane
(a) Draw and label the typical structure of plasma membrane.
3. Movement of substances
Molecules or ions Examples : Sodium ionsPassive Transport
Simple diffusion Small, ___________and uncharged molecules
Examples : Carbon dioxide Oxygen ________________ Fatty acids
Glycerol
Osmosis Water molecules
Big, water-soluble and uncharged molecules through carrier
protein Examples : Glucose ___________ Small and charged molecules
through pore protein Examples : ions
4. Passive transport
(i) Simple diffusion
Classification : Process (Cl)
Simple diffusion(N)
Characteristics : 1. Transport of substances or molecules (Cr)
2. Down the concentration gradients 3. Without energy
Significance : The process continues until dynamic equilibrium
(S) is achieved
(a) Fill in the blank with the correct answer.Simple diffusion
is a _____________ of transporting substances or molecules from a
region of higher concentration to a region of _______________
concentration without energy. The process continues until dynamic
equilibrium is achieved
Example : Gaseous exchange between alveolus and blood
capillary
Alveolus
CO2O2
Blood capillary
O2
CO2
Object : Carbon dioxide (partial pressure)Condition : Higher in
the blood capillary than in the alveolusCause & Effect : Carbon
dioxide diffuse into the alveolus by simple diffusionResult :
Carbon dioxide is expelled from the lung
Object: Oxygen (partial pressure)Condition : Higher in the
alveolus than in the blood capillaryCause & Effect : Oxygen
diffuse into the blood capillary by simple diffusionResult : Oxygen
is transported to the heart
(a) Explain the process of gaseous exchange in Amoeba.
Concentration of oxygen outside of Amoeba is ___________ than
inside of Amoeba. Oxygen diffuse into the Amoeba by
________________. Oxygen will be used for cellular respiration.
Concentration of carbon dioxide inside the Amoeba is higher than
outside of Amoeba. Carbon dioxide diffuse out by simple diffusion.
Carbon dioxide is ______________ from the Amoeba.
(ii) Facilitated diffusion
Classification : Process (Cl)
Facilitated diffusion(N)
Characteristics : 1. Transport of big molecules or ions (Cr) 2.
Down the concentration gradients 3. Without energy 4. Through pore
or carrier protein
Function : To transport big and specific molecules (F) across
the plasma membrane
(a) Fill in the blank with the correct answer.
Facilitated diffusion is a process of transporting big molecules
or ions from a region of _________ concentration to a region of
__________ concentration without energy. The process occurs through
pore protein or _____________to transport big and specific
molecules into the cell.
Example : Absorption of nutrients in the villusGlucose
Object : Glucose (concentration)Condition : higher in the small
intestine compared to the blood capillary (of the villus)Cause
& Effect : glucose molecules diffuse into the villus by
facilitated diffusionResult : Glucose molecules are transported to
the liver
Blood capillary
(iii) Osmosis
Classification : Process (movement) (Cl)
Osmosis(N)
Characteristics : 1. Movement of water molecules (Cr) 2. Down
the concentration gradients 3. Without energy 4. Through
semi-permeable membrane
Significance : Results in dynamic equilibrium (S)
(a) Fill in the blank with the correct answer.
_____________ is a process of water movement from a region of
higher concentration of water to a region of lower concentration
without energy through ____________________ membrane.. The process
occurs until dynamic equilibrium is achieved.
Example : Absorption of water by root hair cells
SoilparticleObject : Water (concentration)Condition : higher in
the soil solution compared to the cell sap of root hair cell
Cause & Effect : water molecules diffuse into the root hair
cell by osmosis
Result : The cell sap of root hair cell become dilute
Roothair cell
Water molecules
(a) The cell sap of the root hair cells become dilute.
Concentration of water molecules in the soil solution is higher
than in the cell sap of root hair cells
5. Active transport
Classification : Process (Cl)
Active transport(N)
Characteristics : 1. Transport of substances or ions (Cr) 2.
Against concentration gradients 3. Use energy
Significance : Results in elimination or accumulation (S) of
substances
(a) Fill in the blank with the correct answer.Active transport
is a process of transporting substances or _______ from a region of
lower concentration to a region of higher concentration across the
plasma membrane using _________. This type of transport results in
the _______________ or ________________ of molecules and ions from
the cell.
Example : Sodium-Potassium pump
Object : Sodium ions (concentration)Condition : lower inside the
cell than outside the cellCause & Effect : carrier protein
transports sodium ion out of the cell by active transportResult :
The concentration of sodium ions inside the cell is always lower
than outside of the cellObject : Potassium ions
(concentration)Condition : higher inside the cell than outside the
cellCause & Effect : carrier protein transports potassium ion
into the cell by active transportResult : The concentration of
potassium ions inside the cell is always higher than outside of the
cell
(a) Name the process of movement of molecule from : (i) Higher
concentration to the lower concentration -
__________________________ (ii)Lower concentration to the higher
concentration - ___________________________
(b) Name the process of movement of substances across the plasma
membrane for :(i) Water :
_______________________________________________(ii) Glucose :
______________________________________________(iii) Sodium ion :
___________________________________________(iv) Fatty acid :
____________________________________________(v) Amino acid :
_________________________________________(vi) Vitamin A, D, E and K
: _________________________________
(c) Name the process for the following example.(i) Oxygen enters
the cells : _________________________________(ii) Absorption of
glucose in the villus : _____________________(iii) Absorption of
water by the root hair of plant : _________________(iv) Absorption
of potassium ion by plant root hair : ______________(v) Glycerol
enters the cells : _________________________________
6. Compare and contrast passive transport and active
transport.SimilarityBoth passive and active transport allow
substances to move across the plasma membrane.
Differences
AspectPassive transportbutwhilewhereas
Active transport
Energy expenditurePassive transport does not use energy.Active
transport uses energy from ATP.
Carrier protein Simple diffusion does not require carrier
protein. Facilitated diffusion requires carrier protein.Active
transport requires carrier protein.
,Concentration gradientMovement of substances in passive
transport is from higher concentration region to low concentration
region.(goes down the concentration gradient)Movement of substances
in active transport is from lower concentration region to higher
concentration region.(against the concentration gradient)
EquilibriumEquilibrium will be achieved at the end of the
process.Results in accumulation or elimination.
(a) State the differences between passive transport and active
transport. (i)
(ii)
(iii)
(iv)
SUBTOPIC 3.3 : Appreciating the movement of substances across
the plasma membrane1. Things to ponder.Dan tidaklah sama keadaan
dua laut (sekalipun satu jenisnya), yang satu tawar lagi memuaskan
dahaga serta sesuai diminum, sementara yang satu lagi masin lagi
pahit dan (kedua-duanya itu berfaedah kepada kamu): Dari tiap-tiap
satunya kamu dapat makan daging yang lembut hidup-hidup dan dapat
pula kamu mengeluarkan benda-benda perhiasan untuk kamu memakainya;
(selain itu) engkau melihat pula kapal-kapal membelah air belayar
padanya; (diadakan semuanya itu) supaya kamu dapat mencari rezeki
dari limpah kurnia Allah dan supaya kamu bersyukur. [Fathir,
012]
Dan Kami telah jadikan di bumi: Gunung-ganang yang menetapnya,
yang tinggi menjulang; dan Kami telah memberi minum kepada kamu air
yang tawar lagi memuaskan dahaga? [Al Mursalat, 27]
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