Movement Of Substances Into And Out Of Cells + Enzymes MOCKS Flashcards
What is osmosis
Osmosis is the net movement of water molecules from an area of high water potential to an area of low water potential
across a permeable membrane
What is diffusion
Diffusion is when particles spread from an area of high concentration to an area of low concentration. The particles move along a “concentration gradient” and this process uses no energy
What is active transport
Active transport uses energy to move substances against their concentration gradient.The energy comes respiration
Factors affecting rate of diffusion
- Surface Area : Volume- if surface are is large compared to the volume, the rate of diffusion will be faster
- concentration gradient
- distance (travelling a shorter distance)
- temperature (particles move quicker with a higher temperature)
Main biologically important groups of inorganic molecules
Respiratory gases
Water
Minerals
Turgid
When a plant cell is placed in distilled water, the distilled water starts to move by osmosis across the cell membrane and into the vacuole. The cell swells up and the cytoplasm begins to push against the cell wall
Placid
Water leaves the cell by osmosis. The cytoplasm pulls away from the cell wall (plasmolysis) and the cell becomes flaccid and the plant wilts
Role of enzymes
Enzymes are proteins that function as biological catalysts. So, they are molecules that speed up a chemical reaction without being changed by the reaction.
Factors affecting enzyme activity
An increase in temperature beyond the optimum causes the enzyme’s active site to become denatured.
Deviating from the optimum pH (too high or too low) causes the enzyme’s active site to become denatured and the active site loses its important shape
The higher the enzyme concentration, the more enzymes there are to form enzyme-substrate complexes, leading to an increase in enzyme activity.
