- Messages
- 924
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- Points
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20: be careful. It says number of DNA molecules. In the prophase, each chromosome has two chromatids, and each chromatid contains one DNA molecule so 46*2=92. After division, each chromosome consists of only one chromatid each. So 46.http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w04_qp_1.pdf
question
7.answer is A.I had marked B.In which conditions do we add HCl before the Bendicts test or in all?
20.Answer is D.
30.Answer is A.
30: fungi growing in xylem cannot affect development of root pressure, as this is done by the root hair cells moving ions by active transport, not xylem. They certainly cannot affect stomata, and uptake of water by root hair cells also has nothing to do with xylem.
If fungus = affecting xylem, then, we should look for functions of xylems, as THOSE will be affected.
Fungi growing in xylem can affect water passing through it, just like putting our hand in a lake affects the hydrogen bonds the water molecules had before our hand interfered. I think the fungal cell wall or membrane may have hydrophobic or hydrophilic properties that affect the water