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urgent and quick biology help please! (1 Viewer)

misericordia

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hi people, i'm just wondering how do you show the relation ship betwn SA:V ratio and rate of reaction in experiment...i'm completely lost...please help me out:worried:
 

yoakim

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Heya. Well, to start off with: the surface of the cell is the outside area of the cell, and the volume of the cell is the capacity inside the cell.
The surface area controls the rate of removal and absorption of wastes and nutrients, and the volume determines the metabolic needs and waste products. So as the cell grows larger, its rate of exchanging and removing of materials and wastes also decreases, so if the cell grows too big it divides into two cells so that it can maintain an efficient surface area to volume ratio.
Hope that helps :)
 

misericordia

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mmm yoakim thanks...i do get what the task is asking for now, but how can experiment this thingo!? urrgh lost again into another dimension... X(
 

yoakim

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oh right, IN an experiment....haha sorry can't help you there :(
 
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w00dy.

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i found this in my bio book. i hope this is what your asking for...

purpose
to use a model to investigate the effect of
size on sa/v ratio
shape on sa/v ration
sa/v ratio on the rate of diffusion into an object

requirements
agar-phenolphthalein- sodium hydroxide jelly. 4cm thick. cut into cubes. of 3 sizes (sides, 3cm, 2cm, 1cm)
0.1m hcl acid
ruler, blade
paper towel, 250ml beaker, plastic spoon

procedure a effect of sixe on sa/v ratio
take the 3 agar cubes
for each cube calculate suface area:
surface area of 1 side = length (squared) (use cm2 as unit)
total surface area = 6 x length2
calculate volume:
volume = length3 (cubed)
calculate sa/v ratio:
sa/v = cm2/cm3
conclusion: as the cube size decreases the sa/v ratio increases

procedure b effect of shape
(we were given a table with various shapes on it, and had to work out the sa/v ratio)
conclusion: spheres have lower sa/v ratios, flat objects have a higher sa/v ratio

procedure c rate of diffusion
place 3 cubes in a beaker
cover in hcl acid
turn the cubes over every 2 mins with plastic spoon
remove from acid quickly blot dry with paper towel cut each cube in 2 and measure the depth of penetration of the acid in each cube
conclusion: the acid diffused into the smallest cube

overall statement about the significance of sa/v ratio for cell function:
the greater the sa/v ratio the faster diffusion can occur, cells are small often flatish with many internal membranes this maximises their sa/v ratio and thus maximises diffusion


---> i hope at least some or all of the above helped in some way:)
 

misericordia

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Dear wOOdy
yes!!! this is exactly the experiment that i was supposed to come up with!!!!!!!!
you seriously don't know how much you helped me out(seriously
love you mwaaaaah(in friendly way ;-p
thanx A LOT!!!!
 

w00dy.

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misericordia said:
Dear wOOdy
yes!!! this is exactly the experiment that i was supposed to come up with!!!!!!!!
you seriously don't know how much you helped me out(seriously
love you mwaaaaah(in friendly way ;-p
thanx A LOT!!!!
its ok. i kinda sorta had this feeling that what id said was what you needed.


anytime:)
 

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