Transcript Diffusion and Agar Cube Lab Ppt

Determine which cube size shows the
most amount of diffusion using surface
area to volume ratio calculations
Relate lab data to explain why cells
remain small.
Safety: Goggles and Gloves
Using NaOH –wash immediately with water
Always cut away from you when using a knife
Phenolphtalein is an indicator! It is colorless but
Will change color when mixed with a base
Calculate the surface area and volume for the cubes.
Calculate the surface area to volume ratio for the cubes.
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Obtain beaker, knife, spoon, and cardboard
tray.
Carefully cut a 2cm x 2cm x 2cm and a
4cm x 4cm x 4cm agar cube.
Place the 1cm, 2cm and the 4 cm cube into
the beaker.
Carefully pour enough NaOH to cover
cubes. Let stand for 10 minutes. Record
start time.
Complete questions 8, 2, 3, 4, 5, 6, and 7
on the student data sheet.
Why was phenolthalien used in this lab?
Smallest cube showed 100% diffusion and the
Largest had the least. Why?
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Remove the cubes from the NaOH solution
with spoon. Place cubes on your cardboard
tray and carefully blot if necessary with
paper towel.
Cut each block in half and measure the pale
yellow area in the center in centimeters.
Calculate the volume of this yellow region
by multiplying length x width x height.
Complete Table 3.
Draw diagrams of each cube using graph
paper.
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The agar cubes are models which represent cells.
What made each cell different?
What living process is being modeled when you
line up the cubes in the following order: 1cm,
2cm, 4cm?
Which part of the cell cycle would the 1cm cube
be associated with?
Which size cube would represent a cell after
mitosis?
What transport process is represented by the pink
color found within the cubes?
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Someone tells you that a human cheek cell is much larger
than a human blood cell. Which cell would have the larger
surface area to volume ratio?
The _________________ of a cell is being affected faster than
its ____________________ as the amount of cytoplasm
increases within it.
As a cell grows in size, what happens to it nutritional
needs? What transport process needs to change to
accommodate this need?
What does a cell do make sure that it does not grow too
big?
How would an increase in cell size affect the cell’s ability to
get nutrients?
In the lab, what material represented needed nutrient?
A rod shape (rectangular shape) bacterium has the
following dimensions: 4mm long, 2mm wide, and 2mm
deep. (a) What is its surface area to volume ratio? Show all
work.