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Working Document The ForeST greenhouSe
THEORETICAL CAPSULE
(This document is intended for adults.)
2010-2011
Working Document Theoretical capsule
It is important to know …
The objective of this capsule is to give the teaching personnel the opportunity to
acquire a quick and accurate comprehension of what photosynthesis is.
Activity 1 – The characteristics of living organisms and the parts of
plants
Characteristics of living organisms
Several characteristics allow for the distinction between a living organism and a
non living organism. For primary school students, we will concentrate on the
main characteristics. First, we will determine the characteristics that the students
will automatically name:
• breathing
• feeding itself
• growing
• reproducing
• dying
The suggested activities will allow two other characteristics to be brought to the
forefront. It will be important to ensure they are named by the end of the LES:
• moving independently
• cellular organisation.
Here are other characteristics of living organisms:
• reacting to changes in the environment
• adapting
The number of characteristics varies from one source to the other depending on
how they are grouped. A living organism must possess all the characteristics.
Non-living organisms are mostly found in one of the following groups: air, water,
light or earth.
The Allô prof library contains a capsule (in French only) that may guide you.
Here you will find a description of living organisms as well as examples of living
and non-living organisms.
http://biblio.alloprof.qc.ca/PagesAnonymes/DisplayFiches.aspx?ID=6076
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Working Document Parts of the plant
The roots
Usually below ground, the roots allow the plant to affix itself to the earth and to
draw from it the elements that it needs (water, minerals salts) to feed itself. The
roots also allow the sap to circulate, acting somewhat like a pump. They also
are used to store nutrients for hard times.
The stem
The stem is the main part of the plant. The part of the plant located at the earth
level is called the collar. The part where a leaf is affixed is called the node.
The stem's function is to support the other parts of the plant. It also makes the
nutrients (sap) circulate throughout the plant.
The leaves
The leaf is a part of the plant affixed to the stem. Photosynthesis occurs in the
leaves. It is also through the leaves that the plant breathes at night.
The flower
The reproductive organs of plants are found in the flower. It has the male organ
(stamen) or the female organ (pistil) (unisexual) or sometimes even both sexes
(hermaphrodite).
The fruit
The fruit is formed by the plant after the flower, to protect the seeds it produces.
The seed
The seed will one day become another plant.
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Working Document Activity 2 – What is photosynthesis?
PHOTOSYNTHESIS: In plants, photosynthesis ensures food production. In other
words, photosynthesis is the capacity of a plant to transform organic matter from
carbon dioxide (CO2), water (H2O) and solar energy.
This energy, coming from the Sun, allows the leaf containing chlorophyll to
transform the carbon dioxide from the air, and the water and mineral salts from
the earth, into sugar (glucose).
Finally, photosynthesis also produces oxygen, used for living organisms to
breathe.
Photosynthesis
Carbon dioxide (CO2)
Energy
Oxygen (O2)
Phloem sap
(sugar towards the roots)
Xylem sap
(water + mineral salts towards the leaf)
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Working Document Here is an equation that explains the main principles of photosynthesis as well as
an analogy to a cake recipe.
Ingredients
Energy
Result
Cast off
H2O + minerals salts + CO2
Milk + flour + eggs
+
sugar + O2
+
Oven
Cake + vapour (cast off)
… And breathing?
It is important to mention that all parts of a plant (the roots, stem, leaves, flowers
and fruit) breathe. Air exchanges mainly take place in regularly dispersed small
openings called stoma (under the leaves). Breathing takes place regularly day
and night, unlike photosynthesis, which only takes place by day.
The sugar produced during photosynthesis is stored by the plant cells and during
respiration the sugar is burned by the oxygen. The combustion of sugar
(glucose) produces energy, water vapour (H2O) and carbon dioxide (CO2). This
energy will be used in plant reproduction and growth, and will help it to
accomplish its other activities.
Here is a chemical equation that explains the principle of cellular respiration of
the plant:
Sugar + O2
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Energy + CO2 + H2O
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Working Document Perspiration
Just like humans and animals, plants perspire. The plant thus loses water in the
form of vapour. In plants, this phenomenon occurs day and night. Plant
perspiration is essential to photosynthesis.
Three factors influence plant perspiration on our planet, namely temperature,
light and wind.
What is chlorophyll ?
CHLOROPHYLL: Chlorophyll is a coloured pigment present in plants. This pigment
plays a primordial role in photosynthesis in plants. Thus, when plants (their leaves)
are exposed to the light of the Sun, it is chlorophyll, the pigment present in some
of its cells, that absorbs the light.
The plants then use the light, the water absorbed by their roots and the carbon
dioxide absorbed by the leaves, to produce glucose. Glucose is the name of
the sugar that feeds plants.
Once this sugar has been produced in the leaves, it is transported by the sap
towards the other parts of the plant (roots, stem) to feed it. In ecology, it is said
that plants are "producers" (autotrophic living organisms) because they use their
leaves to make their own food.
What is sap ?
SAP: Sap is a liquid that circulates thanks to specialised cells called "vessel
elements" between the various parts of the plant in order to transport the
nutrients necessary to growth. There are two types of sap: xylem sap and
phloem sap.
Xylem sap (before photosynthesis) is a solution of mineral salts, absorbed by the
roots and that mainly circulates in the xylem, or the vessels in the wood. These
wood vessels have the capacity to transport great quantities of water and
nutrients from the ground all the way to that photosynthesis factory: the leaves.
Phloem sap (or feeding) (after photosynthesis) comes mainly from the leaves
following the photosynthesis carried out by the plant. This sap circulates mainly
in the phloem. It contains soluble organic substances, for instance amino acids
and sugars.
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Working Document It is interesting to note that it is phloem sap that man gathers to make sweet
products. Here are some examples: birch sap (syrup, wine, beer, vinegar), sugar
palm sap (supplies palm wine), gum arabic (or acacia) (chewing gum, Turkish
delight, dragées).
Finally, contrary to popular belief, maple syrup is made not from phloem sap
(sap produced after photosynthesis) but rather from the xylem sap of the maple
in springtime, even before photosynthesis has resumed its activity.
The following diagram shows the location of the vessels of a tree trunk through
which the sap circulates.
Bark
Phloem
Xylem
Marrow
Source : http://svt.ac-creteil.fr/local/cache-vignettes/L150xH142/arton534-85733.jpg
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Working Document Some collective demonstrations!
Do plants perspire?
 Materials:
o A green plant
o A plastic bag
 Protocol:
To carry out this experiment, using the plastic bag, you need only hermetically
cover the plant for a few days. You can then observe the droplets of
perspiration that form on the plastic bag.
For more details and photos, refer to the preparation guide, page 2 .
The production of oxygen (O2) by plants
 Materials:
o 2 small fresh aquatic plants (e.g. elodea, also called water weed or
pond weed);
o 2 big beakers (ideally 1000 mL), 2 funnels, 2 test tubes;
o 1 - 100w lamp;
o 1 cardboard box to create obscurity;
To learn about the protocol and the preparation technique, please refer to
pages 3 to 5 of preparation guide.
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Working Document Activity 3 –tropisms
The Online Universalis Encyclopaedia defines tropism thus:
"In plants, tropism, (from Greek tropein: to turn) is a modification of the
direction of growth, that is a curvature caused by an exterior stimulus
and in relation to the direction of the stimulus."
http://www.universalis.fr/encyclopedie/tropismes-vegetaux/
You may consult pages 6 to 8 of the preparation guide in order to familiarise
yourself with the materials necessary to the preparation of various assemblies if
you wish to have them in class, rather than using photos.
There are various tropisms in plants. In primary school, we concentrate on
phototropism, geotropism and hydrotropism.
Phototropism or heliotropism
The stimulus is light. You can see phototropism when the leaves move towards
a light source.
Geotropism or gravitropism
The stimulus is weight. The roots moving downwards and the stems moving
upwards are the result of geotropism.
Hydrotropism
The stimulus is water. Hydrotropism can be observed when we see roots moving
towards the damp side of the assembly.
To go a little further...:
Haptotropism ou thigmotropism
The stimulus is a contact. A climbing plant that rolls itself around a trellis
represent this tropism quite well.
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Working Document Activity 4 – Extraction of chlorophyll by chromatography
The objective of this activity is to experience an experiment that will allow you to
show that there are a variety of pigment colours in a plant leaf.
Pages 9 to 15 of the preparation guide give you various information related to
this laboratory: laboratory materials list, everyday usage materials, labels...
Chromatography is a technique that allows a homogenous mixture to be
separated. In order to demonstrate that a variety of pigment colours exist in the
leaves of a plant, we must extract the chlorophyll from the leaf. In other words,
to separate the coloured elements (the pigments) from our leaf and to make
them move (or spread) onto a piece of chromatographic paper. The principle
is simple: to proceed with the separation and migration of the coloured
pigments from our leaf, we need a strip of filter paper or chromatographic paper
whose end is soaking in a liquid mixture (the solvent (alcohol) and a colour
pigment (chlorophyll)). The elements of the mixture that dissolve better in the
solvent will then migrate quickly to the paper, while those that have a lower
solubility will migrate less quickly or not at all.
In the laboratory in activity 4, we will use chromatography in order to find out
what types of pigments are contained in the leaves we have chosen.
Types of chlorophyll and colour
•
•
•
•
Carotene
Chlorophyll a
Chlorophyll b
Xanthophyll
: Yellowish - orange
: Bluish - green
: Greenish - yellow
: Yellow
http://scienceamusante.net/wiki/index.php?title=La_chlorophylle
Video link:
http://rea.decclic.qc.ca/dec_virtuel/biologie/101-NYA05/Cellule_et_evolution/1.La_Cellule/Chromatographie/cromos.htm
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Working Document Here are websites that allow for the exploration of other facets of plants
Canadian Space agency (characteristics of living organisms and tropisms)
http://www.asc-csa.gc.ca/eng/educators/resources/mars/default.asp
Natural Resources Canada
http://ecosys.cfl.scf.rncan.gc.ca/dynamique-dynamic/respiration-eng.asp
In French only :
A diagram of a plant with definitions http://www.infovisual.info/01/003_fr.html
Maison Léon Provancher - Green life - various activities
http://www.maisonleonprovancher.com/vert.htm
La main à la pâte (Does the water go up the plant? sequence of activities
http://lamap.inrp.fr//?Page_Id=6&Element_Id=44&DomainScienceType_Id=3&ThemeType_Id=9
La main à la pâte (Where does the water from the watering can go? sequence
of activities
http://lamap.inrp.fr//?Page_Id=6&Element_Id=38&DomainScienceType_Id=3&ThemeType_Id=9
Activities relating to photosynthesis:
Resources in chemistry and biology: @chimiebiologie (Extraction of chlorophyll)
http://atchimiebiologie.free.fr/chlorophylle/chlorophylle.html
Resources in chemistry and biology: @chimiebiologie (Oxygen production)
http://atchimiebiologie.free.fr/oxygene/oxygene.html
In French only :
ScienTIC
http://www.scientic.ca/affiche_Article.asp?IdArticle=1006&dest=selection#conclusion
Flash animations related to photosynthesis:
In French only:
Cité des sciences (Animation flash de la photosynthèse)
http://www.citesciences.fr/francais/ala_cite/expo/tempo/planete/portail/labo/carbone/photosyntese.html
BrainPop
http://www.brainpop.fr/fr/category_20/subcategory_215/subjects_1678/
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