2d - Movement of Substances

Diffusion

扩散 (kuòsàn) The net movement of particles from an area of high concentration to an area of low concentration.

Osmosis

渗透作用 (shèntòu zuòyòng) The net movement of water molecules across a partially permeable membrane from a region of high water potential (more water) to low water potential (less water).

Active transport

主动运输 (zhǔdòng yùnshū) The movement of substances across a cell membrane from a region of low concentration to high concentration (against the gradient), requiring energy.

Passive processes

被动过程 (bèidòng guòchéng) Movement of substances across cell membranes that does not require energy from the cell (e.g., diffusion, osmosis, facilitated diffusion).

Rate of diffusion

扩散速率 (kuòsàn sùlǜ) How fast diffusion occurs; affected by concentration gradient, temperature, and surface area.

Turgid

膨胀的 (péngzhàng de) / 细胞饱胀 (xìbāo bǎozhàng) Describes a plant cell that is swollen and firm due to being full of water; helps support the plant.

Hypertonic

高渗的 (gāoshèn de) Describes a solution with a higher solute concentration (lower water potential) than another solution (e.g., inside a cell). Water tends to move out of the cell.

Isotonic

等渗的 (děngshèn de) Describes a solution with the same solute concentration (same water potential) as another solution (e.g., inside a cell). No net movement of water.

Hypotonic

低渗的 (dīshèn de) Describes a solution with a lower solute concentration (higher water potential) than another solution (e.g., inside a cell). Water tends to move into the cell.

Endocytosis

内吞作用 (nèitūn zuòyòng) The process where a cell takes in large substances from the outside by engulfing them with its cell membrane, forming a vesicle. Requires energy.

Exocytosis

外排作用 (wàipái zuòyòng) The process where a cell releases large substances from inside by fusing a vesicle containing the substance with the cell membrane. Requires energy.

Facilitated Diffusion

易化扩散 (yìhuà kuòsàn) / 协助扩散 (xiézhù kuòsàn) The passive movement of specific molecules across a cell membrane through transport proteins, down their concentration gradient (no energy needed).

Transport Proteins

转运蛋白 (zhuǎnyùn dànbái) Proteins embedded in the cell membrane that help move specific substances across it (e.g., in facilitated diffusion and active transport).

Flaccid

萎蔫的 (wěiniān de) / 松弛的 (sōngchí de) Describes a plant cell that has lost some water and is soft or limp; the cell membrane is not pressing firmly against the cell wall.

Plasmolysed

质壁分离的 (zhìbì fēnlí de) Describes a plant cell where the cytoplasm and cell membrane have pulled away from the cell wall due to significant water loss by osmosis (e.g., in a hypertonic solution).

Crenation

细胞皱缩 (xìbāo zhòusuō) The shriveling of an animal cell when it loses water by osmosis in a hypertonic solution.

Lysis

细胞裂解 (xìbāo lièjiě) / 溶血 (róngxuè - for RBCs) The bursting of an animal cell when it takes in too much water by osmosis in a hypotonic solution.