Biology Paper 1

[tensed123]

Q. In an animal cell which process is dependent upon cell surface area  and which process is dependent upon cell volume ?

mcq number 24 , june 2007 .. help me out
                           

[unknown 101]

Q. In an animal cell which process is dependent upon cell surface area  and which process is dependent upon cell volume ?

mcq number 24 , june 2007 .. help me out
                           

answer is C
hormones are the only ones dependant because if the surface area is larger then more receptors will be able to identify the hormone
all the others have nothing to do with surface area, carbon dioxide is dependant of cell volume because if its larger then more cell organelles are present so more respiration occurs!

hope this helped..

[unknown 101]

Q 21, jun 07

why is it 20

[3ishakay]

Q 21, jun 07

why is it 20

hey, its like

a double stranded DNAs got 120 nucleotides ..

its askin fr the max length of the poly peptide chain

so first the mRNA only uses the 60 nucleotides as the template
cus it wont use both strands ..

and then 60/3 = 20 ..

i hope i made sens ..
im horribl at explainin things ..

[unknown 101]

hey, its like

a double stranded DNAs got 120 nucleotides ..

its askin fr the max length of the poly peptide chain

so first the mRNA only uses the 60 nucleotides as the template
cus it wont use both strands ..

and then 60/3 = 20 ..

i hope i made sens ..
im horribl at explainin things ..

i know the first part about 60 nucleotides, but why do u divide it by 3?
and Thanks anyways

[nid404]

1 amino acid=3 nucleotides

[unknown 101]

1 amino acid=3 nucleotides

yea i got it, Thanks

[ruby92]

m/j 2006 q 17
and o/n 2006 1

[unknown 101]

m/j 2006 q 17
and o/n 2006 1

m/j Q17: if it was first put in 0.35 mol.dm-3, and no change occured then that means conc. gradient inside the cell and outside are the same, when u decrease conc. to 0.1, sucrose inside the cell will diffuse outside down a conc. gradient.
so that means that solutes r lost from the cell, increasing pressure potential.
hope this helped

[ruby92]

wont pressure potential increase if water moves into cell.
here water is moving out.
the pressure potential should decrease.
the cell will become flaccid??

[unknown 101]

wont pressure potential increase if water moves into cell.
here water is moving out.
the pressure potential should decrease.
the cell will become flaccid??

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]

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

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]

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......

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