Inside the cell Outside the cell lextracellular fluid) Substances X and Y may be

Question

Inside the cell Outside the cell lextracellular fluid) Substances X and Y may be any substances other than water Letter size indicates relative concentrations of substances X and Y on each side of the membrane. Therefore, the concentrations of X and Y are greater inside the cell than outside. The solute concentrations of the extracellular fluid and cytoplasm are measured in milliosmols (mOs), which is the number of dissolved particles per milliliter (ml) of solution. 13. Substance X can passively cross the membrane in the direction of the green arrow by binding to a membrane transport protein. By which mechanism does substance X cross the membrane? a. simple diffusion b. osmosis c. active transport d. facilitated diffusion e. filtration Solute concentration: 300 mOs Solute concentration: 500 mOs Plasma membrane lipid bilayer) Provide an explanation for your answer: Substance Y is an ion that binds to a membrane transport protein to cross the mem- brane in the direction of the blue arrow: By which mechanism does substance Y cross the membrane? 14. a. simple diffusion b osmosis c. active transport ion pump) d faciltated diffusion e. receptor-mediated endocytosis Provide an explanation for your answer:

Explanation / Answer

13) facilitated diffusion (it is diffusion as the solute is moving down the gradient across a semi- permeable membrane. The movement is driven by its concentration gradient. It is termed as facilitated because it us unable to cross/diffuse across the membrane without help. It is aided by a specialized membrane protein called carrier which helps its transport from one side of the membrane to the other.

14)c. Active transport (ion pump) = a transport mechanism us termed as active when energy is spent in fulfilling the process. As can be seen since Y is transported against its concentration gradient there would be no force driving it and hence energy is to be provided in doing so. Hence u can say that the ion is pumped from one side of the membrane(low concentration) to the other (high concentration).

15)a. From extracellular to cytoplasm.

The osmotic pressure is high in the cytoplasm (500mOsm) as compared to the extracellular matrix. High osmotic pressure/ osmolarity would mean that solute concentration is more and water amount is less. Thus water is more outside and less inside(cytoplasm. Hence it will move down its concentration/ amount gradients.

16)there are 3types of endocytosis -phagocytosis, pinocytosis and receptor assisted.

Similarity between all 3 is that they all enter the cell engulfed in a vesicle (endosome in general) which pinches off from the membrane in the cytoplasm and it's contents gets absorbed by the cell.

Difference lies in the substance engulfed involved. Pagocytosis involves engulfing food or foreign entities which are digested as lysosome fuses with the endosome. Pinocytosis involves engulfing fluids, the solutes in which are later absorbed. Receptor mediated allows engulment of ligand of the receptor which are bound to it. Hence the 1st 2 is nonspecific while the last one is highly specific.

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

---