Download pass through the cell membrane

Cytoplasmic Organelles
Centrioles
•Made of microtubules.
•Small, paired, tiny structures near the
nuclear envelope.
•Most active during cell division.
•They are not found in plant cells.
Cytoplasmic Organelles:
Centrioles
Movement of Materials Through
The Cell Membrane
For a cell to maintain its internal environment,
it has to be selective in the materials it allows to
cross its cell membrane.
Transport: How molecules and fluids pass
through the cell membrane.
Movement of Materials Through
The Cell Membrane
Movement of molecules across the cell
membrane depends on:
(A) concentration difference
(B) membrane permeability
(C) size and type of particle
(D) temperature and pressure
Movement of Materials Through
The Cell Membrane
Three types of passive transport (i.e., no energy
is required).
1. Diffusion: The process by which molecules of
a substance move from an area of higher
concentration of that substance to areas of
lower concentrations.
Movement of Materials Through
The Cell Membrane: Diffusion
Movement of Materials Through
The Cell Membrane
2. Osmosis: The diffusion of water molecules
through a selectively permeable membrane
from an area of higher concentration of water to
an area of lower concentration of water.
It continues until equilibrium is reached.
Movement of Materials Through
The Cell Membrane: Osmosis
Movement of Materials Through
The Cell Membrane
3. Facilitated diffusion: The use of carrier
proteins to move lipid insoluble substances
through the cell membrane.
Like diffusion and osmosis, no energy is used,
but a concentration difference must exist for
movement to occur. Example, transport of
glucose.
Movement of Materials Through The
Cell Membrane: Facilitated Diffusion
Movement of Materials Through
The Cell Membrane
Active Transport
It is an energy-requiring process.
It enables substances that do not diffuse into the
cell to move against the natural flow.
That is, materials cross the plasma membrane
against a concentration difference.
Movement of Materials Through
The Cell Membrane
Three types of active transport
1. Individual molecules are carried through
membrane-associated pumps.
These pumps depend on energy (ATP).
Movement of Materials Through
The Cell Membrane
For example, the sodium-potassium pump. It
ushers out sodium ions (Na+) and brings in
potassium ions (K+) across the cell membrane.
These pumps are common in nerve and kidney
cells.
Movement of Materials Through The
Cell Membrane: Active Transport