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Corso metodologico didattico CLIL Inglese Emilia Romagna 2013 -‘14
Unità di apprendimento CLIL
LANGUAGE
ENGLISH
LEVEL
B1 Common European Framework of Reference
TITLE
Inside and Outside the Cell
AUTHORS
Carla Cardano, Giovanna Ferrari, Simona Santoro, Claudia Terzi
SUBJECT
SCIENCE (BIOLOGY)
CONTENTS
Passive and active transport across the cell membrane
CLASS
3 Liceo Linguistico (Scuola Secondaria Superiore)
TIME
12 hours
STEP 1: Activities presentation (1h)
STEPS
STEP 2: Introducing passive and active transport across the cell
membrane, lessons with activities (2 + 2 h)
STEP 3: Lab activity: observation of osmosis in plant cells using
microscopes (3h)
STEP 4: Lab activity: observation of osmosis in animal cells
watching and transcribing a video (2h)
STEP 5: Assessment and final review (2h)
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Corso metodologico didattico CLIL Inglese Emilia Romagna 2013 -‘14
Unità di apprendimento CLIL
Inside and Outside the cell
Carla Cardano, Giovanna Ferrari, Simona Santoro, Claudia Terzi
1. CONTEST
Subject: Science (Biology)
Teacher: subject teacher
Target: learners from 3rd year Liceo Linguistico (Scuola Secondaria Superiore)
Timing: 12 hours
2. CONTENTS
Active and passive transport across the cell membrane
All the contents are taught in L2 (English)
2.1 Detailed contents
Diffusion and osmosis as physical phenomena
Osmosis, diffusion and facilitated diffusion across the cell membrane
Active transport across the cell membrane: sodium-potassium pump as the main example
Endocytosis and exocytosis (phagocytosis and pinocytosis)
3. OBJECTIVES
3.1 Content objectives
General objectives
To learn how to work in a team
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To develop analysis, synthesis, reprocessing and abstraction skills
To develop a scientific way of reading facts
Specific objectives
To distinguish between passive transport and active transport
To identify the involvement of membrane proteins in active transport processes and cell
communication
To explain passive transport across membranes by diffusion and osmosis
To explain turgor and plasmolysis in plant cells
To explain the meaning of the words hypotonic, isotonic and hypertonic with respect to
solutions of different solute concentration
To describe and explain the role of the ion pump in the active transport of materials in and out
of cells
To recognize that endocytosis and exocytosis are active transport processes that move
material into and out of the cell
Prerequisites
The student knows the general features of animal and plant cells
The student knows the fluid mosaic model of the plasma membrane
The student knows the function of ATP
The student knows the meaning of hydrophobic and hydrophilic characters of molecules
The student knows how to use a microscope
The student knows how to prepare a wet mount
Learning outcomes
At the end of the unit, students should be able to describe the role of the plasma membrane in
separating and connecting the internal environment of the cell from and with the external
environment
3.2 Language
General objectives
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To motivate the learner
To encourage the learner's self-development in dealing with new topics
To promote the learner's language autonomy
To guide and support the learner in the process of language-learning through scientific
contents
To show more autonomy and improvement in spoken activities in L2
To develop self-confidence in using L2
To activate cognitive processes (implicit and explicit) in L2
To get used to consult on-line monolingual dictionaries, which exhibit pronunciation both in
the phonetic alphabet and as spoken words
To recognize some common origins of words and to consult the on line etymology
dictionaries, when necessary
To recognize special words: those scientific words that are used in a more general context,
those that are “false friends”, others that are “italianised” when translated in Italian, etc.
Specific objectives
To explain the main concepts of active and passive transport in English
To recognize and explain the key words
To build a specific glossary and define the terms in it
To pronounce difficult words correctly
Prerequisites
Students can understand simple written and spoken language (level B1)
Students can produce simple written texts
Students can report on a given topic
Learning outcomes
At the end of the unit students should be able:
To read short scientific texts and analyse information for operative purposes
To understand simple instructions to carry on experiments
To produce simple lab reports using a given scheme
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To summarize information about the active and passive transport
To report about the active and passive transport using a clear specialized lexicon (CALP)
correctly
To use and re-employ the acquired knowledge in L1 or in L2 independently of the language of
acquisition
4. ORGANIZATION
Activities
Whole-class lesson, brainstorming, texts reading, videos and animations watching and
listening, lab experiments, lab reports, team work
Materials
Step 1: everyday school material (blackboard, copybooks, pens...), textbook
Step 2: everyday school material, student’s worksheet with written texts and links, computer
lab with Internet connection and earphones and IWB (Interactive White Board) in the
classroom.
Step 3: everyday school material, student’s worksheet, lab materials
Step 4: everyday school material, student’s worksheet, computer lab with Internet connection
and earphones
Step 5: everyday school material, computer lab with Internet connection and IWB (Interactive
White Board) in the classroom
Lab activities
In step 3 and 4
ASSESSMENT
In CLIL the primary focus of assessment is on content even if language is always present.
Language evaluation should be closely linked to the achievement of content objectives using
performance-based assessments.
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Students will receive marks between 0 and 10 based on:
­ Knowledge of the main concepts
­ Comprehension of the main concepts
­ Ability in logical elaboration (analysis, synthesis, interpretation)
And a formative assessment based on:
­ Communication
­ Use of a specific lexicon (CALP)
Assessment test
Intermediate: at the end of steps 2, 3 and 4 both summative (content) and formative
(language)
Final: at the end of steps 5 both summative (content) and formative (language)
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Step 1: ACTIVITIES PRESENTATION (1 hour)
Aims:
1- To motivate the students
2- To inform the students about the activities they will perform
3- To explain the importance of using L2 (English) studying a Science topic
4- To explain how this approach can improve both their linguistic and scientific skills
5- To recall and review previous knowledge on the cell and the plasma membrane
6- To build a glossary
Methodology:
1- Whole class lesson
2- Warm up activity
3- Team work
Activities:
1. Whole class lesson: the teacher presents the topic of the learning unit, the main
steps and the methodology (time, assessment, …). The teacher explains the
importance of studying a scientific subject in English. The teacher explains that the
students will improve both their linguistic and specific scientific skills using this
approach.
2. Warm up activity: the teacher elicits the recalling of previous knowledge about the cell
structure, the difference between eukaryotic animal and plant cell, the structure of the
cell membrane and hydrophilic/lipophilic characters of molecules, asking questions
such as:
• Do you remember the difference between a membrane and a wall?
• Does anybody want to come and draw a phospholipids molecule on the
blackboard? Do you remember the different behaviour of the head and the
tails of this molecule?
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• Do you remember if other compounds are found in the structure of the cell
membrane?
• How many names of cellular organelles do you recall?
• Which ones of these are found in animal cells?
• What are their functions?
• And what about plant cells?
• Can we make a list of common and different features between these cells?
• ……
At the end of the brainstorming the students should have guided the teacher to draw on
the blackboard a scheme of the eukaryotic animal and plant cell, and a scheme of the
structure of the cell membrane.
3. Team work: the students are divided in small groups (3-4 students) and they are
asked to build a glossary with terms related to parts of the cell (they can use the book
and their notes). The glossary and the schemes will be collected in the student’s
worksheet.
Material:
Student’s worksheet, blackboard, copybooks, pens, textbook
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Students worksheet step 1
CELL GLOSSARY
Cell: A basic unit of living matter separated from its environment by a plasma membrane; the
fundamental structural unit of life.
Plasma (or cell) membrane: Thin, two-layered film that surrounds entire cell and acts as a selective
barrier. Consists of two layers of phosphlipid molecules embedded with proteins.
Phospholipids: Molecules that constitute the inner bilayer of biological membranes, having a polar,
hydrophilic head and a nonpolar, hydrophobic tail.
Cytoplasm: The fluid like material inside the plasma membrane and outside the nucleus of the cell.
Various organelles are found here and many reactions occur here.
Cytoskeleton: A network of microtubules, microfilaments, and intermediate filaments that branch
throughout the cytoplasm and serve a variety of mechanical and transport functions.
Nucleus: Structure containing the chromosomes and DNA of the cell, which carry hereditary
information and direct the biochemical activities. This is separated from the rest of the cell by the
nuclear membrane.
Another scientific meaning: the positively charged central portion of an atom that comprises nearly all
of the atomic mass and that consists of protons and usually neutrons.
Origin of the word: New Latin, from Latin, First Known Use: 1704. The origin explains the most used
plural form, nuclei
Chromatin: The complex of DNA and proteins that makes up a eukaryotic chromosome. When the
cell is not dividing, chromatin exists as a mass of very long, thin fibres that are not visible with a light
microscope.
Nucleolus: Structure within the nucleus that is involved in the synthesis of RNA found in ribosomes.
Origin of the word: New Latin, from Latin, first used in 1845, diminutive of nucleus; plural form: nucleoli
Endoplasmic reticulum (ER): A network of channels in the cytoplasm that function in synthesizing,
transporting, and storing substances made in the cell.
Smooth ER: That portion of the endoplasmic reticulum that is free of ribosomes.
Ribosomes: Small structures made of RNA and protein, which are the sites of protein synthesis.
There are large numbers of ribosomes in the cell, which may be free in the cytoplasm or attached to
the surface of the endoplasmic reticulum.
Rough endoplasmic reticulum (RER): That portion of endoplasmic reticulum with embedded
ribosomes.
Mitochondria: Sites of aerobic (requiring oxygen) cellular respiration. Most ATP (form of usable
cellular energy) is made in the mitochondria.
Coined in 1898, from Greek mitos, ”thead” and “khondrion” little granule, diminutive of khondros. Sing:
mitochondrion
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ATP: Abbreviation of adenosine triphosphate the principal energy-carrying compound of the cell.
Golgi body (Golgi apparatus): Membrane bound channels in which materials are synthesized or
packaged.
Apparatus: from Latin, new Latin, 1620s: apparatus
Lysosomes: Structures that contain digestive enzymes and which take part in the digestion of food
materials.
Origin: 1950–55, lyso- and -some. Lyso-: “loosening, dissolving”, from Greek lysis
Vacuoles: Membrane enclosed spaces in the cytoplasm containing water and other materials. Many
one-celled organisms have food vacuoles in which ingested food is stored and digested, and
contractile vacuoles that pump excess water out of the cell.
1853, from French vacuole, from Latin vacuus, “empty”
Centrioles (found in a centrosome): Cylindrical structures found just outside the nucleus in animal
cells. These participate in animal cell division.
Cell Wall: A nonliving structure composed mainly of cellulose, which surrounds the cell (outside
plasma membrane) and gives it strength and rigidity; usually present in plant cells. It has pores or
openings that permit free passage of water and dissolved substances.
Chloroplasts: Structures found in plant cells, algae, and some other Protists that contain the green
pigment chlorophyll and are the sites of photosynthesis.
From Greek chlōrós: light green, greenish, yellow
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Step 2: INTRODUCING PASSIVE AND ACTIVE TRANSPORT ACROSS THE CELL
MEMBRANE (2 + 2 h)
Aims:
1- To learn how to work in a team
2- To understand the difference between passive and active transport
3- To understand the process of diffusion and osmosis
4- To understand the role of membrane proteins
5- To recognize the different mechanisms of active transport
6- To build a glossary
7- To focus on key words and forms
8- To focus on grammar structures
Methodology:
1- Whole class lesson using IWB
2- Working in pair or in a team
3- Individual work
4- Computer work
Activities:
1a) The teacher gives a short lesson on Passive transport using animations on the IWB from
the following sites (1+1h):
http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter2/animation__how_di
ffusion_works.html How Diffusion Works
http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter2/animation__how_o
smosis_works.html How Osmosis Works
http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter2/animation__how_fa
cilitated_diffusion_works.html How facilitated diffusion works
2a) Students are divided into small groups (2-3 students). Each group has to work on a
student’s worksheet given by the teacher. On the worksheet students find a guide to what
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they have seen, a text to read and a link to a Biology site with animations:
http://www.phschool.com/science/biology_place/biocoach/biomembrane1/osmosis.html
Student should now write the key words related to passive transport and build a specific
glossary. The glossary will be collected in the student’s worksheet.
The teacher makes a list of new or difficult words asking the students to participate. Irregular
plurals, irregular verbs, difficult pronunciations are pointed out (Focus on words).
The teacher asks the students to underline common structures used in the texts and to
recognize active and passive forms (Focus on structures)
1b) The teacher gives a short lesson on active transport by means of animations on the IWB
from the following sites: (1 + 1h)
http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter2/animation__how_th
e_sodium_potassium_pump_works.html How the Sodium Potassium Pump Works
http://www.sophia.org/tutorials/endocytosis-and-exocytosis--2 Endocytosis and Exocytosis
http://www.youtube.com/watch?v=InG6xF9D4EM Pinocytosis
http://www.youtube.com/watch?v=a1xPpsxvhVA Phagocytosis
2b) Again student are divided into small groups and receive a worksheet. Student should now
write the key words related to active transport and build a specific glossary. The glossary will
be collected in the student’s worksheet.
The teacher makes a list of new or difficult words asking the students to participate. Irregular
plurals, irregular verbs, difficult pronunciations are pointed out (Focus on words).
The teacher asks the students to underline common structures used in the texts and to
recognize active and passive forms (Focus on structures)
3) Intermediate test (reading and listening comprehension, questions, definitions) to check
concepts, glossary and structures (1+1h).
Materials:
Student’s worksheets, computer, blackboard, pens
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Students Worksheet on Passive Transport step 2
1a) Listen to the lesson on Passive transport: diffusion, osmosis, facilitated diffusion on the
IWB
2a) Perform the following class activities:
1) Remember this short description of passive transport:
In passive transport, a solute moves down its concentration gradient and no energy
input is required. Diffusion, facilitated diffusion and osmosis carry out passive
transport
2) Read about concentrations of solutions: Isotonic, Hypotonic, and Hypertonic Solutions
Water moves readily across cell membranes and if the total concentration of all dissolved
solutes is not equal on both sides, there will be net movement of water molecules into or out
of the cell. Whether there is net movement of water into or out of the cell and which direction it
moves depends on whether the cell’s environment is isotonic, hypotonic, or hypertonic.
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3) Read about Plant and Animal Cells in Hypotonic Environments
Turgor in Plants
Plant cells are surrounded by
rigid cell walls. When plant cells
are exposed to hypotonic
environments, water rushes into
the cell, and the cell swells, but is
kept from breaking by the rigid
wall layer. The pressure of the
cell pushing against the wall is
called turgor pressure, and is the
desired state for most plant
tissues. For instance, placing a
wilted celery stalk or lettuce leaf
in a hypotonic environment of
pure water, will often revive the
leaf by inducing turgor in the plant
cells.
Lysis in Animals
Animal cells lack rigid cell walls. When they
are exposed to hypotonic environments, water
rushes into the cell, and the cell swells.
Eventually, if water is not removed from the
cell, the pressure will exceed the tensile
strength of the cell, and it will burst open, or
lyse. Many single-celled protists living in
freshwater environments have contractile
vacuoles that pump water back out of the cell
in order to maintain osmotic equilibrium and
avoid lysis.
4) Read about Cells in Hypertonic Solutions
Hypertonic comes from the Greek "hyper," meaning over, and "tonos," meaning
stretching. In a hypertonic solution the total concentration of all dissolved solute
particles is greater than that of another solution, or greater than the concentration in a
cell.
If concentrations of dissolved solutes are greater outside the cell, the concentration of
water outside is correspondingly lower. As a result, water inside the cell will flow
outwards to attain equilibrium, causing the cell to shrink. As cells lose water, they lose
the ability to function or divide. Hypertonic environments such as concentrated brines
or syrups have been used since antiquity for food preservation because microbial cells
that would otherwise cause spoilage are dehydrated in these very hypertonic
environments and are unable to function.
Texts from: Pearson Education, Inc. or its affiliates and
http://learn.genetics.utah.edu/content/cells/insidestory/
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5) What do you think would happen to cells in an isotonic solution? ………………………….
…………………………………………………………………………………………………………
6) Watch the following animation:
http://www.phschool.com/science/biology_place/biocoach/biomembrane1/osmosis.html
7) Now write the key words related to passive transport and build a specific glossary, paying
attention to the origin of words (etymology), irregular plural forms, irregular verbs, and difficult
or unlikely pronunciations. You may use a monolingual on-line dictionary.
8) Underline common structures and recognize active and passive forms
9) Then listen to the teacher and answer to questions
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Students Worksheet on Active Transport step 2
1a) Listen to the lesson on Active transport: The sodium Potassium Pump, Exocytosis and
Endocytosis (pinocytosis, phagocytosis) on the IWB
2a) Perform the following class activities:
1) Remember this short description of active transport:
Active transport uses energy to move a solute "uphill" against its concentration
gradient. Pumps work, Exocytosis and Endocytosis carry out active transport.
2) Read the following text:
Most living cells maintain internal environments that are different from their extracellular
environment, as well as concentration differences between the cytosol and internal
compartments. In human tissues, for example, all cells have a higher concentration of Na+
outside the cell than inside, and a higher concentration of K+ inside the cell than outside.
Like pushing an object uphill, moving a molecule against a concentration gradient requires
energy. Cells have evolved active transport proteins that can use energy to establish and
maintain concentration gradients.
3) Transcribe the spoken and written text in the video
http://www.sophia.org/tutorials/endocytosis-and-exocytosis--2 Endocytosis and Exocytosis
4) Transcribe the text written in the animations
http://www.youtube.com/watch?v=InG6xF9D4EM and
http://www.youtube.com/watch?v=a1xPpsxvhVA on pinocytosis and phagocytosis
5). Read the following short text on cell communication:
Cells communicate by sending and receiving signals. Signals may come from the
environment, or they may come from other cells. In order to trigger a response, these signals
must be transmitted across the cell membrane. Sometimes the signal itself can cross the
membrane. Other times the signal works by interacting with receptor proteins. Signals may
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simultaneously trigger many different signalling pathways. Each step in a signalling pathway
provides an opportunity for cross-talk between different signals. Through cross-talk, the cell
integrates information from many different signalling pathways to initiate an appropriate
response
Texts from: Pearson Education, Inc. or its affiliates and http://learn.genetics.utah.edu/content/cells/insidestory/
6) Now write the key words related to active transport and cell communication and build a
specific glossary, paying attention to the origin of words (etymology), irregular plural forms,
irregular verbs, and difficult or unlikely pronunciations. You may use monolingual on-line
dictionary.
7) Underline common structures and recognize active and passive forms
8) Then listen to the teacher and answer to questions
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PASSIVE AND ACTIVE TRANSPORT GLOSSARY
Passive transport: a form of transport that requires no energy from the organism, i.e. diffusion of a
substance from an area of high concentration to one of a lower one.
Active transport: the movement of a substance across a cell membrane against its concentration
gradient, which requires energy from the cell and specific transport proteins.
Carrier proteins: proteins that bind a specific molecule on one side of the membrane, change shape,
and release it on the other.
Channel proteins: proteins forming a pore that a specific ion (or other substance) can pass through.
Concentration gradient: change in concentration of a solute across distance, as a gradient within a
cell or across a membrane; if molecules are free to move, they will diffuse along the gradient from
higher to lower concentrations.
Diffusion: the movement of a substance from an area of high concentration to an area of lower
concentration until equilibrium is reached.
Dissolving: the process by which a substance breaks apart into distinct particles (atoms, molecules,
or ions) upon encountering or being placed in a solvent.
Evaporating: the process by which molecules of a liquid change state and become molecules of a
gas; the molecules themselves remain unchanged; the speed of the molecules and the space between
them increases significantly.
Facilitated diffusion: a form of passive transport that requires protein carriers to cross cell
membranes. A solute moves down its concentration gradient and no energy input is required.
Hypertonic: having a higher concentration of solutes compared to another solution.
From Greek hyper: "over, beyond, overmuch, above measure"
Hypotonic: having a lower concentration of solutes compared to another solution.
From Greek hypo: “under”
Isotonic: two solutions having the same concentrations of solutes.
From Greek isos: “equal to, the same as”
Osmosis: the phenomenon whereby water flows across a selectively permeable membrane from a
hypotonic environment to a hypertonic environment.
Semipermeable (selectively permeable) membrane: a physical barrier which only allows certain
particles (based on size and charge) to pass through it; membranes of organelles and cells are
semipermeable membranes through which small, uncharged molecules such as water, oxygen and
carbon dioxide pass freely.
From Latin semi-: “half”
Saturated solution: condition when a solvent contains so much dissolved solute that no more solute
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can be dissolved without adding more solvent or increasing the temperature.
Solute: a substance that has been dissolved or could be dissolved in another substance (solvent).
Solution: homogeneous mixture of two or more substances formed when one substance (solute) has
been dissolved in another (solvent).
Solvent: a substance capable of dissolving other substances.
Osmoregulation: the ability of a cell or an organism to regulate its internal concentration of water or
salts in order to maintain itself in a specific environment.
Phenomenon: something that can be observed and studied and that typically is unusual or difficult to
understand or explain fully
plural phe·nom·e·na or phe·nom·e·nons
Origin: Late Latin phaenomenon, from Greek phainomenon: ”that which appears or is seen”
Sodium-potassium pump: a special transport protein in the plasma membrane of animal cells that
transports sodium out of and potassium into the cell against their concentration gradients.
Endocytosis: is the movement of materials into a cell via membranous vesicles.
Origin: New Latin, from endo- and –cytosis First Known Use: 1963
Phagocytosis: or "cell eating," (a form of endocytosis) the cell engulfs debris, bacteria, or other
sizable objects.
From Greek phago- “ eating, devouring” and –cytosis.
Pinocytosis: or "cell drinking," (a form of endocytosis) the cell engulfs extracellular fluid, including
molecules such as sugars and proteins.
From Greek pinein “to drink” and -cytosis
Receptor-mediated endocytosis (RME): another form of endocytosis, that requires specific
membrane receptors that recognize a particular ligand and bind to it.
Exocytosis: is the movement of materials out of a cell via membranous vesicles.
New Latin, from exo-, “out” and -cytosis
Plasmolysis: the act of becoming plasmolysed.
First Known Use: 1883 From Greek lysis, “a loosening”.
Plasmolysed: when a living cell with a cell wall is placed in a hypertonic solution it loses water by
osmosis, if sufficient water is lost the cell membrane is pulled away from the cell wall and the cell is
said to be plasmolysed.
Turgid: firm, the opposite of flaccid, cells with wall become firm as a result of the uptake of water by
osmosis.
Turgor: (pressure) the force exerted on a cell wall by a cell membrane as a result of osmotic uptake of
water.
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Step 3: LAB ACTIVITY (3 h)
Aims:
1- To understand and follow simple instructions
2- To learn how to work in a team
3- To prepare a wet mount of a plant tissue (red radish)
4- To watch turgor and plasmolysis
5- To explain the role of osmosis in plant cells
6- To prepare a lab report
7- To assess students’ learning/understanding
8- To focus on key words and forms
9- To focus on grammar structures
Methodology:
1- Laboratory work
2- Team work
Activities:
Students working as individuals or in pairs, depending on the number of microscopes
available could carry out this activity. If a video camera connected with a microscope is
available the images can be projected for all to see.
Students work following oral instructions given by the teacher. When the teacher gives
instructions the students are asked to take notes about them, and about the materials and the
tools they need, ready on the counter, and to write down the procedure they will follow (they
already know how to use a compound microscope and how to prepare a wet mount of a plant
tissue).
A single layer of plant cells is placed on a microscope slide and either distilled water, 0,9% or
10% sodium chloride solution is added to the cells. Osmosis will occur resulting in either
turgid cells or plasmolysed cells.
Students draw and take picture of what they see in the microscopes, write their own
observations and fill a lab report within a given scheme. They also answer questions about
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the observed data.
Materials
Student’s worksheet with assessment questions and lab report scheme. Light microscopes.
Microscope with camera if available. Lab material: red radish cut into slices approximately 1
cm wide, microscope slides (1 per specimen), cover slips (1 per specimen), distilled water,
sodium chloride solution 0.9% and 10% w/v, teat pipettes, forceps, pieces of filter paper.
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ASSESSMENT ACTIVITIES STEP 3
Answer with no more than five lines the following questions on the lab activity,
before writing the lab report.
1- How do you calculate the total magnification
of a microscope?
2-­‐ Which is the concentration of the saline
solution? 3-­‐ A hypotonic solution has a concentration of…………….while a hypertonic one is of…….. 4-­‐ Which is the procedure to focus a
microscope? 5-­‐ How do you prepare a wet mount? 6-­‐ Which is the best magnification in order to
observe the osmosis phenomenon? 7-­‐ Why did you choose the red radish as a
sample? 23
8-­‐ Could you distinguish the cell wall from the
membrane? 9-­‐ What happens when you put the tissue in a
hypertonic solution? Does the cell wall
influence this phenomenon? 10-­‐ Describe what you observe when you put
the tissue in a hypotonic solution. How do
you name this process? 24
LAB REPORT
Date
Class
Name of the
student/students:
Title of the
experiment:
Objective/s of the
experiment:
Context, topics,
definitions..:
Materials:
Lab tools:
Procedure:
Data collection:
Data analysis:
Data processing:
Conclusion (related
to the objective/s):
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Step 4: LAB ACTIVITY (2 h)
Aims:
1- To understand and follow simple instructions
2- To learn how to work in a team
3- To explain the role of osmosis in animal cells
4- To write a transcription of a video
5- To assess students’ learning/understanding
6- To focus on key words and forms
7- To focus on grammar structures
Methodology:
1- Laboratory activity
2- Group work
Activities:
The teacher explains to the students that they are going to watch a short video on osmosis:
Egg Osmosis (Hypertonic vs. Hypotonic solution) where two shell-less eggs are used as
single cells to observe osmosis.
The teacher tells the students what happens in the first part of the video: at the beginning egg
shells are removed using acetic acid, leaving the semi-permeable membranes exposed. Only
afterwards one egg is put in a hypertonic solution, the other in a hypotonic one.
The teacher makes the student notice that in the video the term semi-permeable membrane is
used, instead of simply membrane as in a previous animation (but meaning again a
membrane that allows the passage of water molecules only).
Then, working in very small groups students follow the instructions given in the student’s
worksheet
Materials:
Everyday school material, attached student’s worksheet, personal pcs with Internet
connection and earphones.
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Students Worksheet step 4
- Listen to the teacher and take notes
- Watch the video http://www.youtube.com/watch?v=SSS3EtKAzYc on osmosis on your
computer, until minute 2’ 57’’, take notes and write observations.
- Work in pair for transcribing the script of the video starting from minute 2’ 57’’, when the title
“ Placing eggs in a hypotonic and hypertonic solution” appears, till the end (minute 5’ 37’’).
- Select the most significant words in the script and explain them using a monolingual on-line
dictionary.
………………………………………………..………………………………………………..
………………………………………………..………………………………………………..
………………………………………………..………………………………………………..
………………………………………………..………………………………………………..
………………………………………………..………………………………………………..
………………………………………………..………………………………………………..
………………………………………………..………………………………………………..
………………………………………………..………………………………………………..
………………………………………………..………………………………………………..
- Listen to the pronunciation of the following words using a dictionary on line:
Dehydration
Semi-permeable membrane
27
STEP 5: FINAL ASSESSMENT (2 h)
FINAL REPORT
(writing and speaking)
Students work in small groups using interactive speaking and produce a final paper with the
discussion and the integration of the results and observations of the lab activities of steps 3
and 4 on osmosis in plant and animal cells. All the papers are read to the class.
Personal computers are used.
FINAL TEST
(writing and reading)
Students work individually and answer to multiple-choice questions, fill-in-the-blanks
questions and complete a crossword scheme.
FINAL REVIEW
Students watch a short, enjoyable video (Cell membranes rap), using IWB to review and reenforce what learnt in the unit
http://www.youtube.com/watch?v=Pfu1DE9PK2w (3’ 40’’)
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Student worksheet step 5
Answer to the following multiple-choice questions:
1. What is the difference between active transport (AT) and facilitated diffusion (FD)?
❏
AT requires protein carriers; FD does not
❏
AT requires energy; FD does not
❏
AT requires a concentration gradient; FD does not
❏
All of the above
2. In a lipid bilayer the lipids have:
❏
their water repelling tails facing inward
❏
their water repelling heads facing inward
❏
no relationship with water
❏
very rigid and strong bonds
3. Which of the following is necessary in order for osmosis to occur?
❏
a permeable membrane
❏
a semi-permeable membrane
❏
an isotonic solution
❏
ATP
4. If a cell has a solute concentration of 0.07% which of the solutions would be hypotonic
to the cell?
❏
0.01% solute
❏
0.1% solute
❏
1% solute
❏
10% solute
5. During surgery, exposed tissues are moistened with sterile solution to prevent
shrinkage or lysis of the cells. This solution must be _________ relative to cells in the
tissue.
❏
hypertonic
❏
hypotonic
❏
isotonic
❏
it doesn’t matter
6. Why do plant cells behave differently to animal cells when placed in a hypotonic
solution?
❏
Plant cells are permeable to water
❏
Plant cells do not carry out active transport
❏
Plant cells contain a vacuole
❏
Plant cells have a cell wall
29
7. The sodium-potassium pump is an example of:
❏
active transport
❏
endocytosis
❏
exocytosis
❏
passive transport
8. After eating a salty snack like potato chips, the cells in your mouth become saturated
with salt. What happens to the cells in your mouth as they react to the elevated salt
environment?
❏
water moves out of the cell causing them to shrink.
❏
salt moves into the cell causing them to burst.
❏
water moves into the cell causing them to burst.
❏
salt moves out of the cell causing them to shrink.
9. When a cytoplasmic vesicle fuses with the cell membrane and releases its contents
outside the cell, this process is called:
❏
endocytosis
❏
pinocytosis
❏
phagocytosis
❏
exocytosis
10. A contractile vacuole is an organelle that pumps excess water out of many freshwater
protozoan cells. A freshwater protozoan was placed in solution A and observed to form
contractile vacuoles at a rate of 11 per minute. The same protozoan was then placed in
solution B and observed to form contractile vacuoles at a rate of 4 per minute. Based
on this information, which of the following statements is correct?
❏
solution A is hypertonic to solution B
❏
solution B is hypertonic to solution A
❏
solution A and B are isotonic
❏
solution A and B are isotonic to the protozoan cell
Fill-in-the-blanks
For each of the following sentences, fill-in-the-blanks with the correct word selected from the
list. Use each word only once.
channel; hydrophilic; passive; active; carrier
A. Carrier proteins and channel proteins can provide a ________ pathway through the
membrane for specific polar solutes or inorganic ions.
B. A substance is transported down its concentration gradient by ________ transport.
C. A substance is transported up its concentration gradient by ________ transport.
D. ________ proteins can transport a substance down its concentration gradient only.
E. ________ proteins are highly selective in the solutes they transport, binding the solute at a
specific site.
30
CROSSWORD from http://hrsbstaff.ednet.ns.ca/macinness/BIO11__cells.htm
Across 5. Taking in water droplets. 7. Transport that requires energy. 9. Environment that results in net movement of water into cell. 10. Form of active transport out of cell. 13. Small sac formed by plasma membrane. 14. Form of active transport into cell. 15. Environment that results in net movement of water out of cell. 16. Diffusion of water. Down 1. Concentration of water inside cell = outside cell. 2. Transport proteins that change shape. 3. Movement of particles from areas of high to low concentration. 4. Simple type of transport proteins. 5. Amoeba feeding technique. 6. Protein aided passive diffusion. 8. Transport that does not require energy. 10. No net movement of particles. 11. Pressure formed in vacuoles of plant cells. 12. Results from dehydration of plant cells. 31