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Biology
CCEA GCSE biology - osmosis
Osmosis and transpiration are crucial processes in plant biology. Osmosis involves water movement across semi-permeable membranes, while transpiration is the evaporation of water from plant leaves. Both processes are essential for plant survival and are affected by various environmental factors. Understanding these concepts is vital for GCSE and IGCSE biology students.
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Osmosis and transpiration are crucial processes in plant biology. Osmosis involves water movement across semi-permeable membranes, while transpiration is the evaporation of water from plant leaves. Both processes are essential for plant survival and are affected by various environmental factors.... Show more
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This page covers two essential processes in plant biology: osmosis and transpiration. It explains the mechanisms behind these processes and methods to measure transpiration rates.
Osmosis is defined as the movement of water molecules from a dilute solution to a more concentrated solution through a semi-permeable membrane. In plant cells, this process is crucial for maintaining cell structure and function.
Definition: Osmosis is the movement of water from a dilute solution to a more concentrated solution through a semi-permeable membrane.
The semi-permeable membrane allows smaller molecules like water to pass through while blocking larger molecules such as sugar. This selective permeability is key to the osmotic process.
Highlight: The cell wall in plant cells plays a crucial role in osmosis by limiting water uptake and preventing cell damage.
When a plant cell is placed in a hypotonic solution :
In rare cases when a plant cell is surrounded by a hypertonic solution :
Vocabulary: Plasmolysis is the shrinking of the cell contents away from the cell wall due to water loss in a hypertonic environment.
Transpiration is the process of water evaporation from plant leaves. It involves the evaporation of water from mesophyll cells, followed by diffusion through leaf air spaces and stomata.
Definition: Transpiration is the evaporation of water from mesophyll cells, followed by diffusion through leaf air spaces and stomata.
Several environmental factors influence the rate of transpiration:
Example: On a hot, windy day, plants will transpire more rapidly than on a cool, humid day due to increased evaporation rates.
Several methods are used to measure transpiration rates in plants:
Highlight: When using a weight potometer, the compost must be covered with polythene to prevent soil water evaporation from affecting the results.
Example: To compare transpiration rates in sun and shade, leaves could be hung on strings in both locations and their mass loss compared after a set time period.
Understanding these processes and measurement techniques is crucial for students studying plant biology at the GCSE, IGCSE, and A-level stages. These concepts form the foundation for more advanced studies in plant physiology and ecology.
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Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
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This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
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