01: GENERAL BIOLOGY SEMESTER 01
REVIEWER // Q U A R T E R 2 WPSPF
↪ Ions, hydrophilic molecules
CELL MEMBRANE larger than water, and large
molecules such as proteins do
CELL MEMBRANE not move through the membrane
↪ The GATEWAY to the cell on their own.
↪ The cell membrane is the boundary
that separates the living cell from
its surroundings. CHOLESTEROL
↪ The cell membrane exhibits
SELECTIVE PERMIABILITY, allowing ↪ Cholesterol manages the fluidity of
SOME substances to cross it more the membrane and stops the
easily than others. phospholipids sitting too closely
together. This stabilizes them and
reduces the chance of the membrane
COMPONENTS freezing in cold temperatures.
1. Phospholipids
2. Other lipids such as Cholesterol
3. Proteins
4. Carbohydrates
PHOSPHOLIPID
↪ main component in cell membranes.
FLUID-MOSAIC MODEL
They line up in a bilayer arrangement,
● FLUID - because individual
acting as a barrier to water-soluble
phospholipids and proteins can move
molecules.
side-to-side within the layer like it’s a
liquid.
● MOSAIC - because of the pattern
produced by the scattered protein
molecules when the membrane is
viewed from above.
● PHOSPHOLIPIDS in the plasma
membrane can move within the
F bilayer
↪ The cell membrane is made of 2 L ● Most of the lipids, and some
layers of phospholipids called U proteins, drift laterally
S the lipid bilayer I ● Rarely does a molecule flip-flop
O ↪ Hydrophobic molecules pass D transversely across the
L easily; hydrophilic DO NOT. I membrane
U ➔ Materials that are soluble in T
B lipids can pass through the Y
I cell membrane easily.
L ↪ Small molecules and larger
I hydrophobic molecules move
T through easily.
Y ➔ e.g. O2, CO2, H2O
,01: GENERAL BIOLOGY SEMESTER 01
REVIEWER // Q U A R T E R 2 WPSPF
WHAT MAKES THE CELL MEMBRANE FLUID?
(1) TEMPERATURE
↪ The temperature will affect how
the phospholipids move and how
close together they are found.
When it’s cold they are found
closer together and when it’s hot
they move farther apart.
MEMBRANE PROTEINS
● A membrane is a collage of different
proteins, often grouped together,
(2) CHOLESTEROL
embedded in the fluid matrix of the
↪ The cholesterol holds the
lipid bilayer
phospholipids together so that
● Proteins determine most of the
they don’t separate too far, letting
membrane’s specific functions
unwanted substances in, or
FUNCTION OF MEMBRANE PROTEIN
compact too tightly, restricting
1. Transport
movement across the membrane.
2. Cell-cell recognition
3. Enzymatic Activity
4. Signal transduction
5. Intercellular joining
6. Attachment to the cytoskeleton
and extracellular matrix (ECM)
TYPES OF MEMBRANE PROTEIN
(3) SATURATED AND UNSATURATED FATTY
ACIDS
↪ Fatty acids are what make up the
phospholipid tails.
● PERIPHERAL PROTEINS
↪ SATURATED FATTY acids are
↪ are bound to the surface of the
chains of carbon atoms that have
membrane
only single bonds between them.
● INTEGRAL PROTEINS
As a result, the chains are straight
↪ penetrate the hydrophobic core.
and easy to pack tightly.
↪ span the membrane are called
↪ UNSATURATED FATS are chains of
transmembrane proteins
carbon atoms that have double
↪ The hydrophobic regions of an
bonds between some of the
integral protein consist of one or
carbons. The double bonds create
more stretches of nonpolar amino
kinks in the chains, making it
acids, often coiled into alpha
harder for the chains to pack
helices
tightly.
, 01: GENERAL BIOLOGY SEMESTER 01
REVIEWER // Q U A R T E R 2 WPSPF
PARTS OF THE CELL MEMBRANE
1. CARBOHYDRATE CHAIN
➔ on the glycoprotein allows it to act
as a receptor molecule. They can
bind with certain substances and
some act as cell markers for
cell-to-cell recognition.
2. GLYCOLIPIDS
➔ stabilize the cell membrane by
making hydrogen bonds with
nearby water molecules. They
support with cell recognition and
triggering immune responses.
3. CELL - CELL RECOGNITION
PROTEIN TRANSPORT ➔ GLYCOPROTEIN AND GLYCOLIPID
➔ Cells recognize each other by
binding to surface molecules, often
containing carbohydrates, on the
extracellular surface of the plasma
membrane
➔ Carbohydrates on the external side
of the plasma membrane vary
1. CARRIER PROTEIN among species, individuals, and
↪ Proteins create a passageway for even cell types in an individual.
ions and polar molecules to move
through the cell membrane.
↪ CARRIER PROTEIN can transport
substances along or against the
concentration gradient by
changing conformation and
binding to substances.
2. CHANNEL PROTEIN
↪ Channel proteins transport ions
and polar molecules along the
concentration gradient. The pores
allow substances to pass through
without binding to the protein.
REVIEWER // Q U A R T E R 2 WPSPF
↪ Ions, hydrophilic molecules
CELL MEMBRANE larger than water, and large
molecules such as proteins do
CELL MEMBRANE not move through the membrane
↪ The GATEWAY to the cell on their own.
↪ The cell membrane is the boundary
that separates the living cell from
its surroundings. CHOLESTEROL
↪ The cell membrane exhibits
SELECTIVE PERMIABILITY, allowing ↪ Cholesterol manages the fluidity of
SOME substances to cross it more the membrane and stops the
easily than others. phospholipids sitting too closely
together. This stabilizes them and
reduces the chance of the membrane
COMPONENTS freezing in cold temperatures.
1. Phospholipids
2. Other lipids such as Cholesterol
3. Proteins
4. Carbohydrates
PHOSPHOLIPID
↪ main component in cell membranes.
FLUID-MOSAIC MODEL
They line up in a bilayer arrangement,
● FLUID - because individual
acting as a barrier to water-soluble
phospholipids and proteins can move
molecules.
side-to-side within the layer like it’s a
liquid.
● MOSAIC - because of the pattern
produced by the scattered protein
molecules when the membrane is
viewed from above.
● PHOSPHOLIPIDS in the plasma
membrane can move within the
F bilayer
↪ The cell membrane is made of 2 L ● Most of the lipids, and some
layers of phospholipids called U proteins, drift laterally
S the lipid bilayer I ● Rarely does a molecule flip-flop
O ↪ Hydrophobic molecules pass D transversely across the
L easily; hydrophilic DO NOT. I membrane
U ➔ Materials that are soluble in T
B lipids can pass through the Y
I cell membrane easily.
L ↪ Small molecules and larger
I hydrophobic molecules move
T through easily.
Y ➔ e.g. O2, CO2, H2O
,01: GENERAL BIOLOGY SEMESTER 01
REVIEWER // Q U A R T E R 2 WPSPF
WHAT MAKES THE CELL MEMBRANE FLUID?
(1) TEMPERATURE
↪ The temperature will affect how
the phospholipids move and how
close together they are found.
When it’s cold they are found
closer together and when it’s hot
they move farther apart.
MEMBRANE PROTEINS
● A membrane is a collage of different
proteins, often grouped together,
(2) CHOLESTEROL
embedded in the fluid matrix of the
↪ The cholesterol holds the
lipid bilayer
phospholipids together so that
● Proteins determine most of the
they don’t separate too far, letting
membrane’s specific functions
unwanted substances in, or
FUNCTION OF MEMBRANE PROTEIN
compact too tightly, restricting
1. Transport
movement across the membrane.
2. Cell-cell recognition
3. Enzymatic Activity
4. Signal transduction
5. Intercellular joining
6. Attachment to the cytoskeleton
and extracellular matrix (ECM)
TYPES OF MEMBRANE PROTEIN
(3) SATURATED AND UNSATURATED FATTY
ACIDS
↪ Fatty acids are what make up the
phospholipid tails.
● PERIPHERAL PROTEINS
↪ SATURATED FATTY acids are
↪ are bound to the surface of the
chains of carbon atoms that have
membrane
only single bonds between them.
● INTEGRAL PROTEINS
As a result, the chains are straight
↪ penetrate the hydrophobic core.
and easy to pack tightly.
↪ span the membrane are called
↪ UNSATURATED FATS are chains of
transmembrane proteins
carbon atoms that have double
↪ The hydrophobic regions of an
bonds between some of the
integral protein consist of one or
carbons. The double bonds create
more stretches of nonpolar amino
kinks in the chains, making it
acids, often coiled into alpha
harder for the chains to pack
helices
tightly.
, 01: GENERAL BIOLOGY SEMESTER 01
REVIEWER // Q U A R T E R 2 WPSPF
PARTS OF THE CELL MEMBRANE
1. CARBOHYDRATE CHAIN
➔ on the glycoprotein allows it to act
as a receptor molecule. They can
bind with certain substances and
some act as cell markers for
cell-to-cell recognition.
2. GLYCOLIPIDS
➔ stabilize the cell membrane by
making hydrogen bonds with
nearby water molecules. They
support with cell recognition and
triggering immune responses.
3. CELL - CELL RECOGNITION
PROTEIN TRANSPORT ➔ GLYCOPROTEIN AND GLYCOLIPID
➔ Cells recognize each other by
binding to surface molecules, often
containing carbohydrates, on the
extracellular surface of the plasma
membrane
➔ Carbohydrates on the external side
of the plasma membrane vary
1. CARRIER PROTEIN among species, individuals, and
↪ Proteins create a passageway for even cell types in an individual.
ions and polar molecules to move
through the cell membrane.
↪ CARRIER PROTEIN can transport
substances along or against the
concentration gradient by
changing conformation and
binding to substances.
2. CHANNEL PROTEIN
↪ Channel proteins transport ions
and polar molecules along the
concentration gradient. The pores
allow substances to pass through
without binding to the protein.
