I know the answer is A for this question but why is that? I am really struggling to know
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Need help with this OCR AS Biology exam question watch
- Thread Starter
- 28-02-2018 00:34
- 28-02-2018 10:22
So let's break it down
It can't be C, because amylase breaks down starch into glucose - the iodine test will only be positive if starch is present.
Cytoplasms contain proteins. Which are too large to diffuse out of the plasma membrane. So the extra cellular fluid won't show up proteins in a biuret test, but the cytoplasm will. So it cannot be B.
Finally. Starch is broken down by amylase into glucose. Glucose moves from high concentration to low concentration, so out of the cytoplasm, into the extra cellular fluid. Therefore, the extracellular fluid will test positive for the Benedictus test.
Hope this helps!