B2 Flashcards
Describe the structure made by phospholipids in water.
A phospholipid has a hydrophobic phosphate head with two hydrophilic fatty acid tails
Draw the phospholipid bilayer.
x
List locations of lipid bilayers in cells.
Nuclear membrane surrounding the cells nucleus and membrane of cell organelles.
out line the location of aqueous solutions in relation to the lipid bilayer
inside and outside for the cell
state the primary function of the cell membrane
A barrier for materials to enter and exit the cell
Explain why the hydrophonic core of a lipid bilayer has a low permeability to large molecules and hydrophobic particles
Larger molecules cannot fit through the lipid bilayer, only small hydrophobic particles may enter
Describe simple diffusion
no energy required
High to low concentration
Outline the impact of concentration gradient, particle size, particle size, and polarity of molecules on the rate of diffusion across a lipid membrane
a higher gradient accelerates diffusion as molecules move from areas of high to low concentration.
smaller particles diffuse faster due to reduces resistance in the lipid membrane
polr molecules diffuse slower as the repel the hydrophobic lipid bilayer
explain two examples of simple diffusion of molecules into and out of cells
oxygen influx- o2 diffuses from high to low concentration from high to low in the bloodstream»_space; cellular respiration and energy production
CO2 efflux- CO2 diffuses out of the cell high to low concentration» waste removal preventing cellular toxicity.
compare the location of integral and peripheral proteins in the membrane
Peripheral proteins are located in the inner or outer surface of the bilayer. Integral is embedded in the whole bilayer with hydrophobic and hydrophilic areas
Outine how the hydrophobic and hydrophilic structures of proteins impact their anchoring to the membrane
Hydrophobic regions pass through membranes and interact with hydrophilic tails of the lipid molecules in the interior of the bilayer away from water. Hyroph
List at least four functions of membrane bound proteins
Transport proteins- facilitate movement of molecules in and out out of cell
Recognition
receptors
hormones
enzymes
Define osmosis
osmosis is the passivetransport of after molecules from low to high concentration until it reaches equilibrium
predict the direction of water movement based upon differenced in solute concentration
if a solute has a high concentration, water will avoid it and when a solute has a low concentration it will follow it.
Outline the steucute and function of aquaporin proteins
aquaporins are integral channel proteins. Their purpose is to increase membrane permeability to water by selectively transporting water rapidly through membranes
Describe the structure and function of channel proteins
channel proteins are integral membrane proteins that form hydrophillic channels across the membranes, these allow specific molecules to pass through following the concentration gradient.
facilitated diffusion
the passive transport of molecules from high to low through channel
Outline the specificity of channel proteins for ions
Specific ions and molecules have different channel proteins that will alow them to pass through the membrane
Describe one example of facilitated diffusion through a protein channel.
The trasnportation of oxygen in the blood is an example of facilitaded diffusion. The diffusion of blood occurs as a result of higher pressure on one side of the membrane and a lower concentration
Describe the structure and function of pump proteins, including the role of specificity, conformational change and ATP.
The function of pump proteins are to transport specific ions and molecules against the concentration gradient using ATP. The particle binds to the binding site on a specific pump then ATP bindes to the pump and hydrolezes, then becoing ADP.
Compare active transport using a pump protein to facilitate diffusion using a channel protein.
A channel protein will allow a specific particle through a cell membrane following the concnetraion gradient but an active transport protein will use energy to allow a specific molecule through the membran against the concentration gradient.
Define selective permeability.
Selective permeability does not include simple diffusion as it requires energy. It is allowed by facilitated diffusion and active transport and ATP. Small molecules pass through easily whereas larger molecules do not. molecules with a charge are allowed to pass through
Outline how channels and pumps in the membrane allow for selective permeability.
Facilitaded diffusion allows selective permeability by only allowing specific particles to pass through protein channels.
Describe why simple diffusion is not selective.
Simple diffusion is not selective because any small hydrophobic particle is allowed to pass through. If it were selective there would only be certain particles allowed to pass through.
Outline the structure of glycoproteins and glycolipids
Glycoproteins- attached to a protien with a carbohydrate chain attached on the outside surface of cell
Glycolipids- attached to a phosplipid with a carbohydrate chain attached on the outside of the surface of the cell.
Describe the role of glycoproteins and glycolipids in cell adhesion and cell recognition.
Glycoproteins interact with glycoroteins on neighbooring cells, allowing formation of tissues.
Glycoproteins and glycolipids allows the immune system to recongize which cells are its own or invaders.
Draw the fluid mosaic model
What processes depend on active transport in biological systems? (3)
Some procceses that depend on active transport in the biological system are Nutirent uptakes, cell detoxification, and uptake and release of neurotransmitters. Nutrients like glucose use active transporters to enter the cell. The export of wastes like drugs and toxins happens due to active transporters. Vesicular transporters actively transpot neurotransmitters to synaptic terminals.
What are the roles of cell membranes in the interaction of a cell with its environment (3
Selective permeability, cell recognition, and cell communication are very important roles of cell membranes during interactions with other cells in it environment. Selectiv permeability allows for the membrane to transport specific ions and molecules to obtain the flow of nutrients and more. Cell recognition allows the immune system to differentiate itself from others. FInally, cell communication plays a role in cell adhesion allowing cells to communicate and form tissues.
