UNIT 2: Movement through cell membranes

Question 1

selective permeability

Answer 1

refers to the cell membrane controlling what substances enter and leave the cell.
is controlled by proteins embedded in the cell membrane

Question 2

diffusion

Answer 2

the movement of particles from a region of high concentration to a region of low concentration (i.e. down a concentration gradient) e.g. oxygen and carbon dioxide diffuse across the alveolus membranes from regions of relatively high concentration to a region of relatively low concentration.

Question 3

osmosis

Answer 3

the movement of water molecules from a region of high water concentration to a region of low water concentration across a semi-permeable membrane e.g. water is continuously moving across the membrane of an amoeba by osmosis from the freshwater to the interior of the cell

Question 4

application of osmosis

Answer 4

used by the food industry for preservation of food e.g. tinned fruit / vegetables are places in concentrated sugar or salt solution.- this causes any bacteria / fungi present to die due to water leaving the cells

Question 5

turgor

Answer 5

The outward pressure of the cytoplasm and vacuole against the cell wall of a plant

Question 6

plasmolysis

Answer 6

the loss of water from a plant cell such that the cell membrane detaches from the cell wall