Qualification > Sciences
Biology Paper 1 and 3 help HERE ONLY!!!
hmh:
--- Quote from: goin4dakill on June 07, 2009, 04:36:07 pm ---
--- Quote from: hmh on June 07, 2009, 04:29:33 pm ---
--- Quote from: ang3l on June 07, 2009, 04:28:55 pm ---Can anyone help me with these questions..
Q:Describe how the structure of Xylem tissue is adapted to its functions And the Mechanism of water movement through Xylem.
Q:How blood provides suitable conditions for the reproduction of viruses.
--- End quote ---
The tracheids, fibres, and vessels present in the xylem, become lignified during development, losing their living contents. This makes the tissue impermeable (to water) so none is lost as water is transported via the xylem. The tracheids' bordered pits allow for the rapid movement of water from cell to cell.
As is with tracheids, the lignification of vessels can occur as rings, spirals, scalariform or reticulate. In the first formed xylem, rings and spirals occur more frequently. This allows for a limited amount of stretching which may occur in young structures.
Both tracheids and vessels provide a pathway for the transportation of water, whilst also contributing to support.
Hope tht helps!
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--- End quote ---
Is that depth needed in the bio syllabus.. please say no!
No its not needed. :)
goin4dakill:
--- Quote from: hmh on June 07, 2009, 04:29:33 pm ---
--- Quote from: ang3l on June 07, 2009, 04:28:55 pm ---Can anyone help me with these questions..
Q:Describe how the structure of Xylem tissue is adapted to its functions And the Mechanism of water movement through Xylem.
Q:How blood provides suitable conditions for the reproduction of viruses.
--- End quote ---
The tracheids, fibres, and vessels present in the xylem, become lignified during development, losing their living contents. This makes the tissue impermeable (to water) so none is lost as water is transported via the xylem. The tracheids' bordered pits allow for the rapid movement of water from cell to cell.
As is with tracheids, the lignification of vessels can occur as rings, spirals, scalariform or reticulate. In the first formed xylem, rings and spirals occur more frequently. This allows for a limited amount of stretching which may occur in young structures.
Both tracheids and vessels provide a pathway for the transportation of water, whilst also contributing to support.
Hope tht helps!
--- End quote ---
I really dont know any of that!!!!!!!!!!!!!! i mean tracheids?
What i know is..
Xylem:
-no cytoplasm
-cells arranged in columsn up the plant
-impregnated with waterproofing and reinforcing materials
-no cross walls (so water doesnt leak)
hmh:
Tracheids are elongated cells in the xylem of vascular plants that serve in the transport of water and mineral salts.
You dont need to know tht in depth m8... i guess i answered in too much detail... srry guys.. dnt be scared :(
nid404:
heyy guys
BEST OF LUCK!!!! for ur exam(s) tomorrow. I hope every1 does well
goin4dakill:
--- Quote from: hmh on June 07, 2009, 04:42:04 pm ---Tracheids are elongated cells in the xylem of vascular plants that serve in the transport of water and mineral salts.
You dont need to know tht in depth m8... i guess i answered in too much detail... srry guys.. dnt be scared :(
--- End quote ---
oh no its fine! just wondering hehe
but now i know what tracheids are :)
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