Transport of Across Membrane Flashcards
Atoms bind together to make _____
Molecules
____ are composed of simple sugars
Complex carbohydrates
Lipids are composed of _____ plus a _______
fatty acids, polar head`
What are the backbones of lipids made of?
Glycerol
This is the hydrophilic part of lipids
Polar head
This is the hydrophobic part of lipids
Fatty acid tails
____ are long chains of amino acids bound together
Proteins
Nucleic acids are composed of chains of __________.
nucleotides
These are building blocks of proteins
Amino acids
What are complex carbohydrates composed of?
Proteins, lipids, and some complex carbohydrates
Why is it called the Fluid Mosaic Model?
It refers to the mixture of lipids and intrinsic proteins in the membrane
Membrane components:
Lipid bilayer, proteins
WHY DO THE FATTY ACID TAILS OF PHOSPHOLIPIDS POINT TOWARD EACH OTHER IN THE MEMBRANE?
They are non-polar, so they are hydrophobic.
What does the final shape of the protein determine?
Its function.
What conditions can denature proteins?
Extreme temperatures
Two types of transport of materials
Passive transport and energy-consuming transport
Processes that are considered passive transport:
Simple diffusion
Facilitated diffusion
Osmosis
Processes that are considered energy-consuming transport: transport:
Active transport
Exo/Endocytosis
The movement of molecules in solution from a high
concentration of that molecule in the direction of a
low concentration
Diffusion
When does movement of molecules stop in diffusion?
When equilibrium is
reached.
WHY DOES PASSIVE DIFFUSION THROUGH THE LIPID LAYER ONLY OCCUR WITH GASES AND SMALL, LIPID-SOLUBLE MOLECULES?
. These substances are nonpolar, and so is the lipid layer.
Why are channel proteins necessary to move hydrophilic ions through the membrane?
Ions are charged; they cannot go through a nonpolar lipid layer.
Process of passive transport by facilitated diffusion
1 Carrier protein
has binding site
for a specific
molecule.
2 Molecule
enters binding
site.
3 Carrier protein
changes shape,
transporting
molecule across
membrane.
4 Carrier protein
resumes original
shape.
The diffusion through a semipermeable membrane.
Osmosis
True or false:
Water moves from its own low concentration to its own high concentration.
False
When the contents of a cell and the fluid around the cell
have the same concentration of dissolved solutes.
How does water move?
What happens to the cell?
isotonic. Water moves in and out in equal amounts. Nothing.
Refers to whether a cell is hypotonic, hypertonic, or isotonic.
Tonicity
When the the fluid around the cell contains less dissolved
solute than the fluid in the cell.
How does water move?
What happens to the cell?
hypotonic. More water enters the cell than leaves. The cell
may swell to the point of bursting.
When the fluid around the cell contains more dissolved
solute than the fluid inside the cell.
How does water move?
What happens to the cell?
hypertonic. More water leaves the cell than enters. The cell
shrinks.
Process of active Transport
1 The transport protein binds both ATP and Ca2+.
2 Energy from ATP
Changes the shape of
the transport protein
and moves the ion
across the membrane.
3 The protein releases
the ion and the
remnants
of ATP (ADP and P) and
closes.
Example of endocytosis.
Phagocytosis
Process when material is enclosed in a vesicle that
fuses with the plasma membrane,
allowing its contents to diffuse out.
Exocytosis
IF A PLANT CELL NEEDS TO CONCENTRATE SUGAR IN A CELL,
WHAT KIND OF TRANSPORT WILL IT USE?
- Simple diffusion.
- Facilitated diffusion.
- Active transport.
- Osmosis.
