WHAT IS CLIL ???
Da alcuni anni nel Liceo Linguistico “Da Vinci” di Alba viene sperimentata la
metodologia CLIL (Content and Language Integrated Learning), anticipando
quanto previsto dalla recente riforma dei Licei.
La metodologia CLIL ha come obiettivo principale l'apprendimento integrato di
lingua straniera (in questo caso: la lingua Inglese) e contenuti di una disciplina
specifica (Biologia).
Nell’anno scolastico 2010/2011 due classi dell’indirizzo linguistico (2aB e 2aC)
hanno affrontato lo studio della fotosintesi in Inglese; allo studio teorico
dell’argomento ha fatto seguito un’attività pratica di laboratorio, nella quale gli
alunni hanno allestito dei vetrini per l’osservazione microscopica della struttura
degli stomi vegetali; l’attività di laboratorio è stata relazionata in lingua Inglese.
Le diapositive che seguono contengono una sintesi dei testi utilizzati per lo
studio della fotosintesi.
Classi coinvolte: 2aB e 2aC Linguistico
Docente Lingua Inglese (classe 2aB): prof.ssa Renata Ceste
Docente Lingua Inglese (classe 2aC): prof.ssa Gabriella Martinelli
Docente Biologia (classi 2aB e 2aC): prof.ssa Roberta Bruno
PHOTOSYNTHESIS
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Autotrophes and Eterotrophes
Equation of photosynthesis
Products of photosynthesis
Factors affecting photosynthesis
Stages of photosynthesis
Chloroplasts
Stomata
AUTOTROPHES AND HETEROTROPHES
An autotroph, also called a
producer, is an organism
that produces complex
organic compounds (such as
carbohydrates) from
simple inorganic molecules
using energy from light (by
photosyntesis) or inorganic
chemical reactions
(chemiosyntesis).
They are the producers in
a food chain, such as
plants on land or Algae in
water.
An heterotroph (such as animals and human beings) is an
organism that cannot produce organic compounds from
inorganic molecules and uses organic carbon for growth and
as energy source.
EQUATION OF PHOTOSYNTHESIS
Photosynthesis comes from
the words synthesis
(formation or putting
together) and photo (light).
In the context of plants
and cell enrgy, the word
photosynthesis means using
light to produce food.
Green plants can absorb
water from the the soil and
carbon dioxide from the
air, and with the help of
light, transform them into
sugar. The residue oxygen
produced during this
process in released into the
air: it is the same oxygen
that human beings and
animals use to breathe.
Plants in this way nurture themselves by transforming raw
materials onto organic products. Plants need an enormous
amount of energy. In this case the radiant energy is given by
solar light from the sun which is captured in the photosynthetic
pigment called chlorophyll.
Glucose is needed for a process called respiration; it is
necessary for the growth of the plant and for plant cell wall;
when glucose is not used immediately, it can be stored as
starch; this is insoluble, and plants use it as a food store.
FACTORS AFFECTING PHOTOSYNTESIS
The rate of photosyntesis may be limited by factors including:
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insufficient carbon dioxide;
insufficient light levels;
low temperature;
insufficient water.
Plant growers may make an artificial environment in their greenhouses so
that the plants grow quickly. They may use electric lighting, and heaters to
keep the plants warm. They may also release carbon dioxide into the air to
increase its concentration.
STAGES OF PHOTOSYNTHESIS
Photosynthesis is a complex process that can be divided into two
related stages.
1) The first stage (light-dipendent reactions) takes place at the
chloroplast’s inner thylakoid membrane system (grana). In the course
of these reactions, sunlight energy splits water; oxygen is a byproduct of these reactions. The sunlight-dependent reactions also
result in the formation of reduced coenzyme NADPH and ATP.
2) ATP and NADPH, together with carbon dioxide, are reactants in
the second stage (light-independent reactions), that occurs in the
stroma. Carbon and oxygen from carbon dioxide are combined with
hydrogen to make sugar (glucose). This is the synthesis part of
photosynthesis. ATP and NADPH are converted back into ADP and
NADP+.
The light-dependent and light-indipendent reactions thus from a
cycle in which the net inputs are water and carbon dioxide, and the
net outputs are oxygen and carbohydrates.
CHLOROPLASTS
Chloroplasts are the photosynthetic organelles in green part of plants
such as leaves. They contain chlorophyll. Chloroplasts are biconvex discs
found in the plant cells. They have a double membrane around them, and
the inner part forms a system of branching membranes called thylakoids.
These membranes are stacked up in some parts of the chloroplast to form
grana (singular granum). Grana are linked together by lamellae (thin, flat
pieces of thylakoid membrane). Chlorophyll is located in the grana.
Between grana there is a water matrix called stroma.
STOMATA
The leaf blade is thin to allow carbon dioxide to diffuse from the air into
the leaf cells and enter the pores called stomata (singular stoma).
A stoma consists of two guard cells. They separate to form a pore
between them. Through these pores pass all the gases (oxygen and carbon
dioxide).
When guard cells are swollen, stomata are open; when they are limp, they
close.