Qualification > Sciences

Biology Paper 1

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unknown 101:

--- Quote from: ruby92 on May 23, 2010, 09:52:30 am ---wont pressure potential increase if water moves into cell.
here water is moving out.
the pressure potential should decrease.
the cell will become flaccid??

--- End quote ---
water will not move out!! because  we are not increasing the conc. of sucrose, we are decreasing it.
so that  means that the sucrose will diffuse out of the cell down a conc. gradient, from an area of higher conc. ( in the cell ) to an area of lower conc. ( in the solution ).

check the possibilites in the question:

A The pressure potential of the cells will become more positive.

B The solute potential of the cell will become more negative. ( more -ve means that more solutes are being taken up into the cell, which is not happening)

C The water potential of the cells will become more negative. ( if it becomes more negative in the cell it means that sucrose is being taken in from the solution, which is not happening)

D The water potential of the solution will become less negative. ( this means that water is mpvong out of the cell and thats not happening)

ruby92:
i get it now thnkx a lot :) :)
any idea on o/n 2006 q1???

unknown 101:

--- Quote from: ruby92 on May 23, 2010, 02:04:40 pm ---i get it now thnkx a lot :) :)
any idea on o/n 2006 q1???

--- End quote ---

anytime ;)

nov 06 :

it tells you to measure the size of a chloroplast ( measure the big one between 60 -70, its about 8 )

now from the first part of the question it shows u that:
1 unit on the stage micrometer = 80 units on the ocular eyepeice
so that means that
if...    1  =  80
then.  x  =  8

cross multiply ( 8/80 = 0.1)
and since the stage micrometer has small divisions of 0.1 mm, multiply the answer to the top part ( 0.1 ) by 100 to get ur answer in micrometres ( which will become 0.1 x 100 = 10 micrometres)
so the answer is B

hope this helped... :)

cashem'up:
hey guys one more tough question

Which function can be carried out by a mature red blood cell?
A active transport
B cell division
C phagocytosis
D protein synthesis

Now answer is A.........how is it possible......???

unknown 101:

--- Quote from: ima_shah2002 on May 23, 2010, 06:23:22 pm ---hey guys one more tough question

Which function can be carried out by a mature red blood cell?
A active transport
B cell division
C phagocytosis
D protein synthesis

Now answer is A.........how is it possible......???

--- End quote ---

answer is A because if u look at the other options :

B cell division ( can not occur because there is no nucleas in the RBC, this is to increase volume available for oxygen transport )

C phagocytosis ( does not have any lysosomes, so it cannot be this option )

D protein synthesis ( as there is no nucleas, thus no DNA is present, so mRNA cannot be formed and so proteins can not be made even if there were any ribosomes )

hope you understood :)

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