Transcript Biology Chapter 8

Biology Chapter 8
Cells and Their
Environment
Sodium-Potassium Pump
• Carrier protein that uses ATP as it moves
potassium ions and sodium ions across the
cell membrane.
Cells
• The human body contains two hundred and
ten different cell types, that are found only in
humans. Every cell in the body has a sodiumpotassium pump
• Along with that there is the fact that there are
over one hundred trillion cells in the body at
any given time.
Cells
• Each cell has a sodium potassium pump, this
pump operates on an automatic mechanism
of active movement that move the ions of
potassium into the plasma membrane of a
cell and the ions of sodium out of the plasma
membrane of a cell.
Lipid Bilayer
• Double layer that makes up a cell membrane
Concentration Gradient
• The difference in the concentration
of a substance across a region.
Facilitated Diffusion
• A form of passive transport that involves membrane
proteins that aid the movement of substances.
Active Transport
• The moving of a substance to an area of
higher concentration, using energy
Passive Transport
• The moving of a substance to an area of lower
concentration without any energy use.
Equilibrium
• The state that exists for a substance when the
substance is distributed evenly across a space.
Hypertonic Solution
Hypotonic Solution
Isotonic Solution
Cells in Solutions
Cells
•The cell-surface markers
identifies the cell type.
Cell Membranes
• The outer surface is polar,
while the interior is nonpolar.
Cells
• By controlling what enters and leaves a cell,
the cell membrane aids in maintaining
homeostasis within the cell.
Cells
• Small nonpolar molecules can pass
unaided through the cell membrane
Diffusion
• Is the movement of a substance
down its concentration gradient
Facilitated Diffusion
• When particles move out of a cell through
facilitated diffusion, the cell does not
experience any change related to energy.
Osmosis
• The diffusion of water through a
selectively permeable membrane
Endocytosis
• Molecules that are too large to be moved
through a cell membrane can be transported
into the cell by endocytosis.
Osmosis
• If the concentration of a sugar solution is
lower outside outside the cell than inside the
cell, water will move into the cell
Sodium-Potassium Pump
• Is used to remove sodium from a cell and
bring potassium into a cell against their
concentration gradients
Vesicles
• Endocytosis always involves the movement of
a vesicle.
Cell Surfaces
• When a molecule fits into the binding site of a
receptor protein on a cell’s surface
– The receptor can open an ion channel in the cell
membrane
– The receptor can act as a n enzyme, causing
chemical changes in the cytoplasm
– The receptor can cause the information of a
second messenger
Receptor Protein
• Membrane receptor
proteins transmit
information into the cell by
responding to signal
molecules
Messengers
• A second messenger always carries a signal
within a cell
Chapter 8 Test is tomorrow