What are the molecules that make the cell surface fuzzy sticky and sugar rich?
Ch. 3 Test
| Question | Answer |
|---|---|
| The molecules that make the cell surface fuzzy, sticky, and sugar-rich are the: | glycoproteins |
| Protein synthesis occurs on the Golgi apparatus in the cell. | False |
| The greater the osmotic pressure, the greater the tendency of water to move into that area. | True |
Which type of membrane protein will be used to bind to hormones?
When a hormone binds to its membrane receptor, a G-protein that is associated with the receptor is activated; G-proteins are proteins separate from receptors that are found in the cell membrane. When a hormone is not bound to the receptor, the G-protein is inactive and is bound to guanosine diphosphate, or GDP.
What proteins bind to molecules and ions on the outside of the cell?
Two classes of proteins that mediate facilitated diffusion are generally distinguished: carrier proteins and channel proteins. Carrier proteins bind specific molecules to be transported on one side of the membrane.
What molecules are responsible for membrane transport?
Carrier proteins and channel proteins are the two major classes of membrane transport proteins. Carrier proteins (also called carriers, permeases, or transporters) bind the specific solute to be transported and undergo a series of conformational changes to transfer the bound solute across the membrane (Figure 11-3).
What structures are responsible for cell transport?
Role of Cytoskeleton in the Cytoplasm Two of these three structures function to aid intracellular transport within the cytoplasm. Microfilaments and microtubules are both components of intracellular transport.
How do large molecules pass through the membrane?
Larger molecules wold require a transport protein in order to cross the cell membrane. There are three modes of transport across the cell membrane: diffusion, facilitated diffusion, and active transport. Facilitated diffusion also transports substances down a concentration gradient.
Why can’t large molecules pass through membrane?
Large polar or ionic molecules, which are hydrophilic, cannot easily cross the phospholipid bilayer. Charged atoms or molecules of any size cannot cross the cell membrane via simple diffusion as the charges are repelled by the hydrophobic tails in the interior of the phospholipid bilayer.
Why do the large molecules stay on their own side of the membrane?
Why are they assuming the large molecules will stay on their own side of the membrane? Because molecules will move from one side to another to come to an equilibrium, or balance of concentration, the _________________________moves from side B to side A, so the water level on side A goes _____________________________.
Which requires a membrane bound carrier for transport?
Lipid-insoluble solutes are transported across the membrane by a carrier protein. Cellular energy is required for the transport. A solute pump is required. Lipid-insoluble solutes are transported across the membrane by a carrier protein.
Can polar molecules pass through the membrane?
Small uncharged polar molecules, such as H2O, also can diffuse through membranes, but larger uncharged polar molecules, such as glucose, cannot. Charged molecules, such as ions, are unable to diffuse through a phospholipid bilayer regardless of size; even H+ ions cannot cross a lipid bilayer by free diffusion.
Can proteins pass through cell membrane?
Proteins cannot passively diffuse across the cell membrane due to their size and polarity. Thus, a delivery system or technique is always required, similar to nucleic acid transfection.
What kinds of molecules pass through a cell membrane most easily?
Explanation: Small and simple molecules like water, H2O , can pass through the cell membrane easily as it is partially permeable.
What is the ability of non polar molecules to move across a membrane unassisted called?
The cell membrane’s main trait is its selective permeability, which means that it allows some substances to cross it easily, but not others. Small molecules that are nonpolar (have no charge) can cross the membrane easily through diffusion, but ions (charged molecules) and larger molecules typically cannot.
What is a common large molecule that uses facilitated diffusion to move across the cell membrane?
A common example of facilitated diffusion is the movement of glucose into the cell, where it is used to make ATP. Although glucose can be more concentrated outside of a cell, it cannot cross the lipid bilayer via simple diffusion because it is both large and polar.
What are the two types of membrane transport?
Movement of solutes across membranes can be divided into two basic types: passive diffusion and active transport.