Evidence 4
Do not move to evidence 5 until instructed to do so
Starch in plants
Plants need glucose (a kind of sugar) to
perform cellular activities
Glucose
The sugars are stored together as starch
until the plant needs it.
Starch
Scientists wanted to learn more about
where starch is stored in a plant, so
they did an experiment.
They chose a plant that had leaves with
white stripes.
Ask your partner: Predictions
Before moving to the next slide, make a
prediction with your partner:
How do you think the different colors of the plant relate
to the number of chloroplasts? Do you think the white
or green part will have more chloroplasts? Do both
colors have the same number of chloroplasts? WHY??
Move to the next slide when you and your
partner have provided solid reasoning for
your prediction
They used a microscope to look at the
white part and the green part of the
leaf to see if there were any
differences.
White Part of leaf
Green Part of leaf
Ask your partner
Before moving to the next slide, ask you
partner:
Which part of the leaf had the most
chloroplasts?
Move to the next slide when you and your
partner agree on an answer
Then, the scientists used iodine to
see what parts contained starch.
Parts that turn blue show that starch is
present. Brown areas are where there is
no starch.
Ask your partner
Before moving to the next slide, ask you
partner:
What color did the white part of the
plant turn when exposed to iodine? What
does that mean?
Move to the next slide when you and your
partner agree on an answer
Ask your partner
Before moving to the next slide, ask you
partner:
What color did the green part of the
plant turn when exposed to iodine? What
does that mean?
Move to the next slide when you and your
partner agree on an answer
Ask your partner
Before moving to the next slide, ask you
partner:
Which part of the plant indicated
starch? Which part of the plant did not?
Move to the next slide when you and your
partner agree on an answer
They took a leaf and covered part of it
with a black piece of paper. Then they
exposed the plant to light.
Ask your partner
Before moving to the next slide, ask you
partner:
What purpose does the black paper
have? What is the independent variable
(what is changed) in this experiment?
Move to the next slide when you and your
partner agree on an answer
They removed the paper, and observed
that the covered part of the leaf that was
green had become much lighter in color.
There was no change to the white part.
Ask your partner: Predictions
Before moving to the next slide, make a
prediction with your partner:
Why did the part of the leaf that was covered by
the black paper get lighter? Why did the white
part of the leaf stay the same?
Move to the next slide when you and your
partner have provided solid reasoning for
your prediction
Then, the scientists used iodine to
see what parts contained starch.
Parts that turn blue show that starch is
present. Brown areas are where there is
no starch.
Ask your partner
Before moving to the next slide, ask you
partner:
What color did the plant under the black
paper turn? What does that mean?
Move to the next slide when you and your
partner agree on an answer
Ask your partner
Before moving to the next slide, ask you
partner:
How are starch, chloroplasts, and light
related? How do you know?
Move to the next slide when you and your
partner agree on an answer
End of Evidence 4
Based upon the evidence you have seen,
construct and initial model explaining what the
chloroplast does, and how! Do not move to
evidence 5 until instructed to do so
Evidence 5
Evidence 5: What makes chloroplasts work?
Chloroplasts have smaller
structures called grana inside
them.
In normal chloroplasts, the grana
are stacks of little disks with
chlorophyll in them.
Chlorophyll is a green chemical
found in the grana.
Scientists are interested in
whether the grana influences
how much glucose is produced
by chloroplasts.
Ask your partner
Before moving to the next slide, ask you
partner:
Where are grana found and what are
scientist’s trying to study about grana?
Move to the next slide when you and your
partner agree on an answer
Evidence 5: Procedure
We studied the structure of chloroplasts from barley. Sometimes
plants have mutated chloroplasts. Mutated chloroplasts do
not have normal grana.
We looked at barley plants with normal chloroplasts, mutated
chloroplasts, and very mutated chloroplasts by looking
through very powerful microscopes.
You can see what we saw on the next slides.
We also measured how much glucose is produced in each kind
of barley plant.
Evidence 5: Results
Plant type
What the chloroplasts
look like through a very
powerful microscope
Leaf
color
How much glucose was
produced in the leaves?
Barley
plants with
normal
chloroplasts
dark
green
Large amounts of glucose
Barley
plants with
mutated
chloroplasts
pale
green
Small amounts of glucose
Barley
plants with
very
mutated
chloroplasts
yellow
No glucose
Ask your partner
Before moving to the next slide, ask you
partner:
What happened to the color of the leaves
as the barley chloroplasts became more
mutated?
Move to the next slide when you and your
partner agree on an answer
Ask your partner
Before moving to the next slide, ask you
partner:
What happened to the amount of glucose
produced in the leaves as the barley
chloroplasts became more mutated?
Move to the next slide when you and your
partner agree on an answer
Ask your partner
Before moving to the next slide, ask you
partner:
How are color of chloroplasts and
glucose production related?
Move to the next slide when you and your
partner agree on an answer