Diffusion and Osmosis a). Explain why the distilled water in the beaker became
colored. Ql). An experiment using the equipment on the right was set up. .1:.1:1"1
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Diffusion and Osmosis Ql)
a)
.1:.1: "1.1
An experiment using the equipment on the right was set up. Explain why the distilled water in the beaker became colored.
b)
Explain why the sugar solution sugar solution (colored with ink)
moved up the capillary tube.
Q2)
Livadia is a Mediterranean village by the sea. In spring, there is flooding and the sea water rises and covers some of the nearby farmland owned by farmer Antonis. When this happens, Antonis has noticed that his crops begin to shrivel and die. Explain why this happens.
Q3)
For each of these sentences, indicate whether the process involved is diffusion or osmosis, by putting a
"0" for
diffusion or an
"0" for
osmosis.
a)
Oxygen crosses the alveoli of the lungs and enters the blood.
b)
Water enters guard cells in the leaves from surrounding cells.
c)
Water moves from the moist stomatal space to the drier atmosphere.
d)
Water enters blood capillaries from surrounding body cells.
e)
Water in the soil crosses into the root hairs.
f)
Water is absorbed out of the kidney tubules and back into the blood stream.
g)
In the blood vessels in the lungs, oxygen enters red blood cells.
h)
Carbon dioxide enters stomata for photosynthesis.
Q4)
Kelly set up an experiment.
She placed one prune in a beaker of
distilled water and another in a very strong sugar solution (syrup).
11
Kelly returned to her experiment 24 hours later. Explain what you would expect to have happened to Prune A and Prune B.
Section One -
Cells
II
5
Diffusion and Osmosis Q5)
Luke carved a boat out of a potato, and played with it in the kitchen sink. He placed salt inside the boat as his cargo and then left it sitting in the water for an hour while he had lunch. When he returned to his boat, he found that it had water inside. The water was not there before lunch and nobody interfered with his boat.
Explain how the water got into the boat.
Q6)
Complete the blanks with these words.
osmosis
diffusion
partially permeable
high water
low water
Osmosis is the movement of
----------------------
water molecules
from a region of concentration to a region of
concentration.
In
----------
----------- , water molecules move
across a
membrane. Osmosis is sometimes called
a special case of
---------------
because water molecules move from a high to
a low concentration of water molecules.
Q7)
This is a diagram of a guard cell: Guard cells are found in leaves and form pores called stomata between them.
a)
To bend and open the pore (stoma),
guard cells must take up water from their surrounding cells.
b)
i)
What process is involved when water enters the guard cells?
ii)
Explain why this process happens.
Gases can move through the stoma. i)
Name two gases that can enter leaves through the pore. ~
ii)
What is the name of the process when molecules move in this way?
Section One -
Cells
6
Diffusion and Osmosis Q8)
By pushing a cork-borer into a cut potato, two identical cylinders of potato were obtained. One cylinder was placed in a 20% sugar solution (a strong solution) and the other was placed in water.
a)
Explain what happens to the length of each potato cylinder.
b)
In another experiment, a range of different concentration solutions were made, from pure water to 20% sugar. It was noticed that the cylinder in one of the middle test tubes did not change length. Explain this result.
Q9)
EI
m
An amoeba is a single-celled organism found in pond water. Water from the pond continually enters the body of the amoeba. To prevent the amoeba bursting, it has vacuoles that collect water and release it to the outside.
a)
By what process does water enter the amoeba?
b)
The pond water also contains the oxygen that the amoeba needs. i) What is the oxygen needed for? ii) How does the amoeba get the oxygen it needs?
vacuole releasing water
c)
i) ii)
d)
b)
-.
Some amoebas live in the salty sea, but they do not have vacuoles. Why don'tthese organisms burst?
Q10)
a)
Name one waste product that would be harmful to the amoeba if it could not get rid of it. By what process does this waste product get into the water?
•••••••• ~
~
I -.
= water entering amoeba
I
joseph's mother showed him how she makes fruit salad. She cut fruit into a bowl and then sprinkled sugar all over the fruit. She placed the bowl in the fridge overnight. When she took out the bowl the following day, joseph noticed that the fruit had liquid all around it. His mother then placed a few drops of food coloring in the middle of the bowl and again returned it to the fridge. i) ii) iii)
What is the liquid in the bowl? Where did it come from? By what process did the liquid appear in the bowl?
Later that day, joseph noticed that the food coloring had spread through much of the liquid. What process had occurred?
Top Tips'
Things tend to spread out - that's all diffusion is. Osmosis is just a special case of • this - when you're talking about water molecules, moving across a partially permeable membrane. They're both random processes- so the organism doesn't expend any energy. If the concentration gradient is in the wrong direction, it'll use active transport instead - which does need energy.
