Question

A single piant cell is placed in an sotoric solution. Salt is then odded to the sokutlion. wwich ot me totowing wouid occur as a resut of the solt addition Water wouid leave the cell by osmoss. causing the volume of the cytoplosm to decreone. Water would entor the cel by osmosis, and the cel would swe t T The added salt would enter the cel cousing the cell to take up water and swel. There would be no osmotic movement of water in response to the odded san What wil happen to a red blood cell (RBC), which has anintornal ion content of Obou109%, "" is pooed into a beaker of pure water? a. The cell will remain the same size because the solution outside the celis isotonic the cel would swell because the water in the beaker is hypotonic relative to the cytoplasm ot the RBC. c. The coll would shrink because the water in the beaker is hypertonic relative to the cytoplasm of tme RBC. d. The cell would shrink because the water in the beaker is hypotonic relotive to the cytoplasm ot the RBC. 8. True or false: In exocytosis, transport vesicles migrate to the membrane, fuse with it, and release ther contents outside the cell True b. False ?. A bacterium engulfed by a white blood cell through phagocytosis will be digested by enzymes containe in a. Nucleus Lysosomes c. Golgi vesicles d. Chlargslests of the following is a correct difference between active transport and facilitated diffusion? a. Active transport requires energy from ATP, and facilitated diffusion does not. b. Active transport involves transport proteins, and facilitated diffusion does not. c. Facilitated diffusion involves transport proteins, and active transport does not. d. Facilitated diffusion can move solutes against a concentration gradient, and active trar Which cannot.
I dont understabd the last 3 questions .

Answer 1

• When two solutions of different concentrations are separated by a selectively permeable (semipermeable or differentially permeable) membrane, the solvent molecules spontaneously move from the zone of lower solute concentration (higher solvent concertation) to the region of higher solute concentration (lower solvent concertation), to reach an equal concentration state on each side of the membrane. This process is termed as osmosis.
• Cell membranes are selectively permeable membrane. When a cell is surrounded by different concentrations of solutions, different effects are observed:
• Hypertonic solution: Concentration of solution outside the cell is higher compared to cell cytoplasm, water from the cell moves out of the cell and the cell shrinks.
• Hypotonic solution: Concentration of solution outside the cell is lower compared to cell cytoplasm, water enters the cell moves out of the cell and the cell swells (become turgid).
• Isotonic solution: Concentration of solution outside the cell is same as that of cell cytoplasm, no net water movement.

6. Answer: a

• When salt is added to a previously isotonic solution, the solution becomes hypertonic.
• Thus, water will move out of the cell by exosmosis and cytoplasm will decrease in volume causing the cell to shrink.

7. Answer: b

• 0.9 % NaCl is isotonic for RBC.
• If it is shifted to pure water, which is hypotonic, water will enter the cell by endosmosis.
• Thus, RBC will swell.

8. True

• Exo is outside, cytos is cell
• Exocytosis is a process of exporting of substances out of the cell, using energy. Usually mediated by vesicles.

• The vesicles move to the cell surface and fuse with the plasma membrane and remove the contents outside the cells by exocytosis.

9.  Answer: b

• Exogenous antigens like bacteria are engulfed by White blood cells, like phagocytes, by the process of phagocytosis.
• Phagocytosis is aided by the presence of pseudopodia like membrane protrusion. A phagosome is thus formed, with ingested material.
• Lysosomes fuse with the phagosomes to form phagolysosomes.
• The lytic enzymes of lysosome help in digestion of the ingested material (bacteria), followed by exocytosis.

10. Answer: a

• Facilitated diffusion or transport: Movement of molecules or ions through membranes, with aid of transmembrane integral proteins, from higher to lower concentration or towards concentration gradient. (without energy expenditure).

  Example: Oxygen binding to hemoglobin in RBC.

• Active transport: Movement of molecules or ions from lower to higher concentrations or against concentration gradient, thus, energy (in primary active transport- in form of ATP, in secondary active transport-in form of electrochemical gradient) is required.

  Example: Electron transport across membranes of mitochondria and chloroplast.