TOPIC:
Transport Across Membrane (Experiment 1,2 and 3)
1.1.1 Experiment 1. Introduction: The study of transport across membrane focuses on effects of different solution concentration on a plant cell. Isotonic, hypotonic and hypertonic solution give different effect on the plant cell whether it shrinks, swells or maintain its shape.
Hypotonic solution is when water molecules move from a high water potential to a low one because of diffusion. The net movement of water is into the cell by osmosis. Isotonic solution is when the cell content has the same solute potential as the solution the cell is in. Thus, there is no net movement of water. Hypertonic solution is the movement of water to a higher solute concentration outside the cell. Hence, the net movement of water is out of the cell by osmosis. In this experiment, onion cell was used to differentiate its shape when a drop of different concentration of sucrose solution is added to it. Any observation and results are recorded.
Materials and Apparatus: 1.nion
1!. "agnetic stirrer# stirring rod
$. Table sugar# sucrose
11. %patula
&. 'istilled water (. %mall knife ). *lass slide +. over slip -. "icroscope . /eakers 0$)! ml )!! ml2 3.4ilterpaper
Results:
The structure of onion in distilled water.
The structure of onion in )5 of sucrose solution.
The structure of onion in &!5 of sucrose solution.
DISCUSSION
In the experiment,the changes in the shape of onion cell when a drop of )5 of sucrose solution is added to the glass slide is unnoticable.This is because )5 of sucrose solution is an isotonic solution. Isotonic solution has same solute potential with the cell content. Therefore,the water molecules move in and out of the cell at the same rate. Thus,the cell maintains its shape.
However , the onion cell swells when a drop of distilled water is added to the glass slide.This is due to the distilled water being a hypotonic solution.Hypotonic solution causes water molecules to move from a high water potential to a low one because of diffusion. Thus,water moves into the cell by osmosis. Hence, the cell will swell and become turgid but will not burst because of the existence of the cell wall.
6hen a drop of &!5 sucrose solution is added to the onion cell,the cell shrink.This results from &!5 sucrose solution is a hypertonic solution. Hypertonic solution is solution which contains low concentration of water than the concentration of water in cell content .Hence,water from the cell moves out of the cell to the suroundings.The plasma membrane begins to pull away from the cell wall and undergoes plasmolysis.
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1.1.2 Experiment 2 Introduction:
The study of transport across membrane focuses on effects of different solution concentration on a plant cell. Isotonic, hypotonic and hypertonic solution give different effect on the plant cell whether it shrinks, swells or maintain its shape.
Hypotonic solution is when water molecules move from a high water potential to a low one because of diffusion. The net movement of water is into the cell by osmosis. Isotonic solution is when the cell content has the same solute potential as the solution the cell is in. Thus, there is no net movement of water. Hypertonic solution is the movement of water to a higher solute concentration outside the cell. Hence, the net movement of water is out of the cell by osmosis.
In this experiment, potato sticks are used to differentiate the effects of different concentration of solution when they are immersed in different concentration of solution in different test tubes respectively.
Materials and Apparatus: 1.otato $.Table salt# 9al &.'istilled water (. %mall knife ). Test tubes +./enchtop digital balance -. %patula
Results %alt concentrati on, w#v
Initial weight of potato stick, g
4inal weight of potato stick, g
T
t
hange in weight, g
t
T
Water loss / gain
T
t
1!5 9al
$.!$
!.)
1.3) !.1
B!.!- B!.!( &.(-
(.-1
Water loss
&.)5 9al
1.3(
!.)
$.!! !.+
!.!+
!.!1
&.!3
1.1
water gain
!.5 9al
$.1$
!.(
$.$1 !.3!
!.!3
!.!+
(.$)
-.1(
Water gain
'istilled water
1.3+
!.-
$.!3 !.3(
!.1&
!.!-
+.+&
.!)
Water gain
0T=thick potato strip, t=thin potato strip2
T
hange in weight, 5
t
Discussion: /ased on the results,there is an increase in the mass of potato sticks when they are immersed in !.5 9al solution and in distilled water%o,!.5 9al solution and distilled water are categorised as hypotonic solution.This is because water molecules diffuse from outside which has high water potential into the cell which is low water potential. However,potato sticks decrease in siCe when immersed in 1!5 9al solution and &.)5 9al solution.Thus,1!5 9al solution and &.)5 9al solution ar e hypertonic solution.This is because water molecules diffuse out of the cell of potato sticks by osmosis resulting in smaller siCe of potato sticks.
Reerence: 1.http:##answers.yahoo.com#;uestion#index<;id=$!!+1!!1$!$!!3AA;(>$.http:##internalandexternalenvironments$!1$.wikispaces.com#Hypertonic, @hypotonic@and@isotonic@effects@on@plants@and@animal@cells.
1.1.! Experiment ! Introduction:
The study of transport across membrane focuses on effects of different solution concentration on a plant cell. Isotonic, hypotonic and hypertonic solution give different effect on the plant cell whether it shrinks, swells or maintain its shape.
Hypotonic solution is when water molecules move from a high water potential to a low one because of diffusion. The net movement of water is into the cell by osmosis. Isotonic solution is when the cell content has the same solute potential as the solution the cell is in. Thus, there is no net movement of water. Hypertonic solution is the movement of water to a higher solute concentration outside the cell. Hence, the net movement of water is out of the cell by osmosis.
In this experiment, red blood cells are used to differentiate the effects of different concentration when the red blood cells are mixed with different solution concentration in different test tubes respectively.
Materials and Apparatus: 1.Table salt# 9al
-. Test tubes
$.'istilled water
. /eakers 0$)! ml )!! ml2
&.-!5 ethanol
3. otton
(. *lass slide
1!. Dancet
). over slip
11. "agnetic stirrer# stirring rod
+. "icroscope
1$. %patula
Results:
The structure of red blood cell in
The structure of red blood cell in
distilled water.
(.!5 9al solution
The structure of red blood cell in !.)5 9al solution
Discussion:
12
/ased on the results, there is no difference in the shape of the red blood cell when
mixed with !.)5 9al solution. This is because !.)5 9al solution is an isotonic solution. Thus, there is no net movement of water. Isotonic solution is when the cell content has the same solute potential as the solution the cell is in.
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However, the red blood cell burst when it is mixed with distilled water. This is because
distilled water is a hypotonic solution. Hypotonic solution is when molecules move from a high water potential to a low one because of diffusion. Thus, net movement of water is into the cell by osmosis. Hence, the red blood cell will burst. The bursting of the red blood cell is known as haemolysis. &2
/ut when the red blood cell is mixed with (.!5 9al solution, the cell shrink.This is
because (.!5 9al solution is a hypertonic solution. Hypertonic solution is the movement of water to a higher solute concentration outside the cell. The net movement of water is out of the cell by osmosis. Thus, the red blood cell shrinks. The shrinking of red blood cell is known as crenation.
Reerences: 1.http:##answers.yahoo.com#;uestion#index<;id=$!!+1!!1$!$!!3AA;(>$.http:##www.google.com.my#search
