Thursday, October 14, 2010

6.2/6.3 Reflections

- I learned that Membranes regulate the transport of substances across the boundary, which only allows only certain substances to pass. Also the membrane maintains a specific chemical environment within each compartment it encloses.
- What I have found difficult to learn about is the selectively permeable membrane and how it just chooses to select some substances over other substances and how it blocks the passages of some substances altogether.
- How do biological systems regulate?- They are able to regulate the transport of substances across the boundary which allows certain to substances to pass so membranes can maintain a specific chemical environment.

4 comments:

  1. A good start. Interesting that you chose regulation. Many students will choose form and function. Make sure to focus on the U-tube demo we did in class to understand how selectively permeable membranes work.

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  2. A part of the reason the selectively permeable membrane cannot allow some substances to cross the membrane is because of there structure. For instance, substances that are hydrophilic cannot pass directly through the membrane because the interior of the membrane is hydrophobic. Another reason is that some particles are too large to pass across the membrane, which is why they need a transport protein. hope this helps O.o

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  3. Only a few molecules like oxygen, carbon dioxide, and water, diffuse freely through the plasma membrane. Selective permeable membrane allows those small molecules to cross the membrane more easily than bigger molecules which need facilitated diffusion to cross the membrane.

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  4. The selectively permeable membrane allows some substances to cross the membrane more easily than others and blocks the passage of some substances all together. In most cells, a few molecules diffuse freely through the plasma membrane.

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