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Cell-transport-updated
Biological science (University of Oxford)
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AQA A Level Biology
Transport Across Membranes
(3.2.3)
Name: ______________________
Lesson My Marks Total Exam Homework Date
Question Checked
Marks
Lesson 1 – Structure of Cell Membranes
Lesson 2 – Factors that affect Membranes
Lesson 3 – Diffusion
Lesson 4 - Osmosis
Lesson 5 – Investigating Water Potential
Lesson 6 – Active and Co-transport
End of Topic Test
Page 1 of 60
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Specification Section
3.2.3 Transport across cell membranes
Opportunities for skills
Content development
The basic structure of all cell membranes, including cell-surface membranes and the
membranes around the cell organelles of eukaryotes, is the same.
The arrangement and any movement of phospholipids, proteins, glycoproteins and
glycolipids in the fluid-mosaic model of membrane structure. Cholesterol may also be
present in cell membranes where it restricts the movement of other molecules making
up the membrane.
Movement across membranes occurs by:
simple diffusion (involving limitations imposed by the nature of the
phospholipid bilayer)
facilitated diffusion (involving the roles of carrier proteins and channel proteins)
osmosis (explained in terms of water potential)
active transport (involving the role of carrier proteins and the importance of
the hydrolysis of ATP)
co-transport (illustrated by the absorption of sodium ions and glucose by cells
lining the mammalian ileum).
Cells may be adapted for rapid transport across their internal or external membranes by
an increase in surface area of, or by an increase in the number of protein channels and
carrier molecules in, their membranes.
Students should be able to: MS 3.2
explain the adaptations of specialised cells in relation to the rate of transport Students could plot the data
across their internal and external membranes from their investigations in an
explain how surface area, number of channel or carrier proteins and differences appropriate format.
in gradients of concentration or water potential affect the rate of movement
MS 3.4
across cell membranes.
Students could determine the
water potential of plant tissues
Required practical 3: Production of a dilution series of a solute to produce a calibration
using the intercept of a graph of,
curve with which to identify the water potential of plant tissue.
eg, water potential of solution
Required practical 4: Investigation into the effect of a named variable on the
against gain/loss of mass.
permeability of cell-surface membranes.
Lesson 1 – Structure of Cell Membranes
Page 2 of 60
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, lOMoARcPSD|59658805
Key Words
Word Definition
Active Movement of a substance from a region where it is in a low concentration to a region where it is in a high
transport concentration. The process requires the expenditure of metabolic energy in the form of ATP.
Bilayer A membrane consisting of two layers of phospholipids.
Carrier A protein completely spanning the phospholipid bilayer which bind to ions or molecules then change shape
Protein in order to move these molecules across the membrane.
Cell
membrane A selectively permeable membrane surrounding the cell and controlling the entry and exit of materials
Lipid that is an important component of cell-surface membranes because it adds strength. Excess in the
Cholesterol blood can lead to atheroma.
The arrangement of the various molecules of the cell-surface membrane. Fluid because the individual
Fluid mosaic phospholipid molecules can move relative to one another and mosaic because the proteins vary in shape,
model size and pattern.
A carbohydrate covalently bonded with a lipid. They act as recognition sites, help maintain stability of the
Glycolipid membrane and help cells attach to one another.
Carbohydrate chains attached to a protein (often extrinsic) which are part of the cell surface membrane.
Glycoprotein They act as recognition sites, help cells to attach to one another and allows cells to recognise one another.
Partially Also called semi-permeable. A partially permeable membrane allows water and other small molecules to
permeable pass through, but not larger molecules such as starch.
How permeable a substance is depends on the size, polarity and charge of the molecule. If it is small, non-
Permeability polar and fat soluble it is very permeable and can pass through the cell membrane.
Triglyceride in which one of the three fatty acid molecules is replaced by a phosphate molecule.
Phospholipid Phospholipids are important in the structure an functioning of plasma membranes.
Plasma Membranes consisting of a phospholipid bilayer found around and within all cells. The cell-surface
Membrane membrane is the plasma membrane that surrounds cells.
Protein A protein completely spanning the phospholipid bilayer which form water-filled tubes to allow water-soluble
Channel ions to diffuse across the membrane.
Notes
All cells are surrounded by a cell membrane (also
called the plasma membrane). The basic structure of
the plasma membranes, including cell-surface
membranes and the membranes around the cell
organelles of eukaryotes, is the same. It is also how
cells communicate with eachother and their
environment.
Plasma membranes are partially permeable and can
control which substances can enter and leave the
cell.
Plasma membranes act as barriers that can create
separate environments: they keep the components
of the cell isolated from the external environment
and compartmentalize cellular functions by
separating the inside of organelles from the
cytoplasm.
Inside the cell, endoplasmic reticulum, golgi, lysosomes, vesicles and vacuoles are surrounded by a single membrane, but
mitochondria and the nucleus are surrounded by a double membrane.
Page 3 of 60
Downloaded by olinder seth ()
Cell-transport-updated
Biological science (University of Oxford)
Scan to open on Studocu
Studocu is not sponsored or endorsed by any college or university
Downloaded by olinder seth ()
, lOMoARcPSD|59658805
AQA A Level Biology
Transport Across Membranes
(3.2.3)
Name: ______________________
Lesson My Marks Total Exam Homework Date
Question Checked
Marks
Lesson 1 – Structure of Cell Membranes
Lesson 2 – Factors that affect Membranes
Lesson 3 – Diffusion
Lesson 4 - Osmosis
Lesson 5 – Investigating Water Potential
Lesson 6 – Active and Co-transport
End of Topic Test
Page 1 of 60
Downloaded by olinder seth ()
, lOMoARcPSD|59658805
Specification Section
3.2.3 Transport across cell membranes
Opportunities for skills
Content development
The basic structure of all cell membranes, including cell-surface membranes and the
membranes around the cell organelles of eukaryotes, is the same.
The arrangement and any movement of phospholipids, proteins, glycoproteins and
glycolipids in the fluid-mosaic model of membrane structure. Cholesterol may also be
present in cell membranes where it restricts the movement of other molecules making
up the membrane.
Movement across membranes occurs by:
simple diffusion (involving limitations imposed by the nature of the
phospholipid bilayer)
facilitated diffusion (involving the roles of carrier proteins and channel proteins)
osmosis (explained in terms of water potential)
active transport (involving the role of carrier proteins and the importance of
the hydrolysis of ATP)
co-transport (illustrated by the absorption of sodium ions and glucose by cells
lining the mammalian ileum).
Cells may be adapted for rapid transport across their internal or external membranes by
an increase in surface area of, or by an increase in the number of protein channels and
carrier molecules in, their membranes.
Students should be able to: MS 3.2
explain the adaptations of specialised cells in relation to the rate of transport Students could plot the data
across their internal and external membranes from their investigations in an
explain how surface area, number of channel or carrier proteins and differences appropriate format.
in gradients of concentration or water potential affect the rate of movement
MS 3.4
across cell membranes.
Students could determine the
water potential of plant tissues
Required practical 3: Production of a dilution series of a solute to produce a calibration
using the intercept of a graph of,
curve with which to identify the water potential of plant tissue.
eg, water potential of solution
Required practical 4: Investigation into the effect of a named variable on the
against gain/loss of mass.
permeability of cell-surface membranes.
Lesson 1 – Structure of Cell Membranes
Page 2 of 60
Downloaded by olinder seth ()
, lOMoARcPSD|59658805
Key Words
Word Definition
Active Movement of a substance from a region where it is in a low concentration to a region where it is in a high
transport concentration. The process requires the expenditure of metabolic energy in the form of ATP.
Bilayer A membrane consisting of two layers of phospholipids.
Carrier A protein completely spanning the phospholipid bilayer which bind to ions or molecules then change shape
Protein in order to move these molecules across the membrane.
Cell
membrane A selectively permeable membrane surrounding the cell and controlling the entry and exit of materials
Lipid that is an important component of cell-surface membranes because it adds strength. Excess in the
Cholesterol blood can lead to atheroma.
The arrangement of the various molecules of the cell-surface membrane. Fluid because the individual
Fluid mosaic phospholipid molecules can move relative to one another and mosaic because the proteins vary in shape,
model size and pattern.
A carbohydrate covalently bonded with a lipid. They act as recognition sites, help maintain stability of the
Glycolipid membrane and help cells attach to one another.
Carbohydrate chains attached to a protein (often extrinsic) which are part of the cell surface membrane.
Glycoprotein They act as recognition sites, help cells to attach to one another and allows cells to recognise one another.
Partially Also called semi-permeable. A partially permeable membrane allows water and other small molecules to
permeable pass through, but not larger molecules such as starch.
How permeable a substance is depends on the size, polarity and charge of the molecule. If it is small, non-
Permeability polar and fat soluble it is very permeable and can pass through the cell membrane.
Triglyceride in which one of the three fatty acid molecules is replaced by a phosphate molecule.
Phospholipid Phospholipids are important in the structure an functioning of plasma membranes.
Plasma Membranes consisting of a phospholipid bilayer found around and within all cells. The cell-surface
Membrane membrane is the plasma membrane that surrounds cells.
Protein A protein completely spanning the phospholipid bilayer which form water-filled tubes to allow water-soluble
Channel ions to diffuse across the membrane.
Notes
All cells are surrounded by a cell membrane (also
called the plasma membrane). The basic structure of
the plasma membranes, including cell-surface
membranes and the membranes around the cell
organelles of eukaryotes, is the same. It is also how
cells communicate with eachother and their
environment.
Plasma membranes are partially permeable and can
control which substances can enter and leave the
cell.
Plasma membranes act as barriers that can create
separate environments: they keep the components
of the cell isolated from the external environment
and compartmentalize cellular functions by
separating the inside of organelles from the
cytoplasm.
Inside the cell, endoplasmic reticulum, golgi, lysosomes, vesicles and vacuoles are surrounded by a single membrane, but
mitochondria and the nucleus are surrounded by a double membrane.
Page 3 of 60
Downloaded by olinder seth ()
