THE CELL

Docenti: Aniello Terracciano Maria Rosaria BarbaritoClasse : 2 b LinguisticoAnno sc.: 2006/07

CLIL PROJECT

Human red blood cells

OBIETTIVI/OBJECTIVES

Sviluppare un atteggiamento positivo verso lo studio della biologia in lingua inglese/ To develop a positive attitude towards the study of Biology

Migliorare la competenza linguistica degli studenti / to improve the students’ linguistic competence

Leggere e comprendere testi scientifici/ to read and to understand scientific texts

Identificare le parole chiave utili per spiegare un argomento/ to identify useful key words in order to explain a topic

Usare termini scientifici appropriati/ to use appropiate scientific terms Spiegare differenze e similarità tra cellule animali e vegetali e

riconoscerle/ to explain differences and similarities between animal cells and plant cells

Comprendere e spiegare la struttura della cellula/ to understand and to explain the structure of the cell

Comprendere che cosa è la clonazione e spiegarlo in modo semplice/ to understand what clonation is and to explain it in a very simple way

What do you know about cells?

Are cells alive? Where are cell located in our body? How do cells know what to do?

Fat Cells

ACTIVITY:MATCH THE ENGLISH WORDS WITH THE ITALIAN ONES

1. Nucleus2. DNA double helix3. Genetic code4. Protein syntesis5. Transcription phase6. Ribosomes7. Lysosomes8. Mitochondrion9. Cellular respiration10. Organelle11. Enzyme12. Digestion13. Nutrient molecule

a. Respirazione cellulare

b. Enzima

c. Ribosoma

d. Lisosoma

e. Molecola nutriente

f. Digestione

g. Nucleo

h. Doppia elica del DNA

i. Fase di trascrizione

j. Sintesi proteica

k. Codice genetico

l. Mitocondrio

m. Organello

WHAT IS THE CELL? The cell is one of the most basic units of life.  There are millions of

different types of cells.  There are cells that are organisms onto themselves, such as microscopic amoeba and bacteria cells.  And there are cells that only function when part of a larger organism, such as the cells that make up your body.  The cell is the smallest unit of life in our bodies.  In the body, there are brain cells, skin cells, liver cells, stomach cells, and the list goes on.  All of these cells have unique functions and features.  And all have some recognizable similarities. 

The one-celled organism 

amoeba proteus

A single-celled bacteria 

of the type: E. coli

A plant cell from the leaf  of a poplar tree

PLASMA MEMBRANE AND NUCLEUS

All cells have a 'skin', called the plasma membrane, protecting it from the outside environment.  The cell membrane regulates the movement of water, nutrients and wastes into and out of the cell.  Inside of the cell membrane are the working parts of the cell.  At the center of the cell is the cell nucleus.  The cell nucleus contains the cell's DNA, the genetic code that coordinates protein synthesis

. Model of a portion of the DNA double helix

The transcription phase of protein synthesis takes places in the cell nucleus.  After this step is complete, the mRNA leaves the nucleus and travels to the cell's ribosomes, where translation occurs.  Another important cellular organelle is the mitochondrion (PLURAL: MITOCHONDRIA) where cellular respiration takes place.

 Other important elements in the life of a cell are the lysosomes.  Lysosomes are organelles that contain enzymes that aid in the digestion of nutrient molecules and other materials. 

Students’activity Give a definition of the cell What types of cells do you know? Give examples of cells of our body What is the function of plasma nembrane? What is at the centre of the cell? What does it contain? Where does the transcription phase of proteins

take place? Where does translation occurr? What is the mitochondrion? What is the mitochondria?

Animal cell and plant cell

    There are many different types of cells.  For example we can make a distinction

between plant cells and animal cells.  While both plant and animal cells contain the structures discussed above, plant cells have some additional specialized structures.  Many animals have skeletons to give their body structure and support.  Plants do not have a skeleton for support .  This is because of a unique cellular structure called the cell wall.  The cell wall is a rigid structure outside of the cell membrane composed mainly of the polysaccharide cellulose.The cell wall gives the plant cell a defined shape which helps support individual parts of plants.  In addition to the cell wall, plant cells contain an organelle called the chloroplast.  The chloroplast allow plants to receive energy from sunlight.       

ANIMAL CELL

PLANT CELL

FILL IN THE BLANK

Plant cells are different from animal cells because they don’t have a ……….Their cell wall is a rigid…… outside of the cell membrane. The chloroplast in an ………. Thanks to it plants can receive …… from ………….

PROKARYOTIC CELL EUKARYOTIC CELL

PROKARYOTIC CELLS EUKARIOTIC CELLS

Small cells (>5mm) Larger cells (>10mm)

Always unicellular Often multicellular

No nucleus or any membrane bound organelles

Always have nucleus and membrane bound organelles

DNA is circular ,without proteins DNA is linear and associated with protein to form chromatin

Ribosomes are small(70s) Ribosomes are large (80s)

No cytoskeleton Always cytoskeleton

Cell division is by binary fission Cell division is by mitosis or meiosis

Reproduction is always asexual Reproduction is sexual or asexual

true/false Prokaryotic cells are larger F

T Eukaryotic cells are unicellular F

T Prokaryotic cells have no cytoskeleton

F T Eukaryotic cells have a linear DNA

F T

CELL SIZE  Cell size can vary: some cells are visible to the eye. For example

an egg of a bird is a single cell and is visible to our eyes. Instead a bacterial cell is very small. It had a diametre from 0.35

to 0.40 micrometer. Cells vary greatly in size. Most cannot be seen without a

microscope, although a few varieties are visible to the naked eye.

The diameter of an average animal cell is about 10 micrometers (or 0.01 millimetre) and of an average plant cell is about 100 micrometers (0,1 millimetre).

Some cells are quite large. Eggs of animals are single cells before their development begins, and they are usually visible to the eye.

Bacterial cells are very small, with diameters of only 0.35 to 0.40 micrometer, near the limit of resolution of an ordinary light microscope.

THE MICROSCOPE

Have you ever seen a cell?When?What do you remember about it?

The microscope is a crucial magnifying tool for examining cells, their processes, and their interactions with the environment.

The Microscope Parts and Specifications

 Historians credit the invention of the compound microscope to the Dutch spectacle maker, Zacharias Janssen, around the year 1590.

Eyepiece Lens:  the lens at the top that you look through.  Tube:  Connects the eyepiece to the objective lensesArm:  Supports the tube and connects it to the baseBase:  The bottom of the microscope, used for supportIlluminator:  A steady light sourceStage:  The flat platform where you place your slides.  Stage clips hold the slides in place.  Revolving Nosepiece or Turret:  This is the part that holds two or more objective lenses and can be rotated to easily change power.Objective Lenses:  Usually you will find 3 or 4 objective lenses on a microscope.  Rack Stop:  This is an adjustment that determines how close the objective lens can get to the slide. Condenser Lens:  The purpose of the condenser lens is to focus the light onto the specimen. Condenser lens can be moved up and down particular objective lens in use.

Examining a plant cell with the microscope

Tools & Materials microscope flat slides cover slips onion skin

USING MICROSCOPE

Objectives : - to give the students the opportunity to see cells and to discover the difference between plant and animal cells.

- To further the students understanding of cells and to give them the experience of using a microscope.

The students will be able to:

1. Describe the differences between plant and animal cells.

2. Operate a microscope.

3. Examine onion cells.

OBSERVING THE PLANT CELLS STEP BY STEP a. First take a piece of onion skin off the onion. b. Put it flat on a slide c. Carefully put on a cover slip remembering to

angle it. e. Examine the cell under low then medium power. f. Ask the teacher to put it on high power. g. Draw a few cells showing what you observed in

the space provided. h. Describe in a few sentences what you saw while

looking at the cell through the microscope.

Students’ activity Now compare and contrast what you have observed. The following vocabulary should be discussed and or defined:

Cell Walls Plants have thick cell walls to strengthen the plant stem.

Cell Membranes Animals have thin membranes because they have other forms of skeletons.

Chloroplasts Green colored structures that produce food.

Nucleus Both plants and animals have these; they control heredity and cell division.

Cytoplasm A clear liquid where most of the cells life functions occur.

(After the discussion the students should have the opportunity to observe the slides again so they may observe the items discussed)

WHAT IS CLONING? Celebrity Sheep Has Died at Age 6

Dolly, the first mammal to be cloned from adult DNA, was put down by lethal injection Feb. 14, 2003. Prior to her death, Dolly had been suffering from lung cancer and crippling arthritis. The unnamed sheep from which Dolly was cloned had died several years prior to her creation. Dolly was a mother to six lambs, bred the old-fashioned way.

QUESTIONS

Who is Dolly? How was it born? How long did it live? Had it any health problems Had it any lambs? How were they born? Why was Dolly so famous?

Are there different types of cloning?

DNA CLONING

THERAPEUTIC CLONINGREPRODUCTIVE CLONING

DNA CLONING

A DNA fragment is transferred from one organism to a self-replicating genetic element

THERAPEUTIC CLONING

Also called “embryo cloning” is the reproduction of human embryos for use in research.The aim is not to create cloned human beings but to harvest stem cells to treat disease.

REPRODUCTIVE CLONING It is a technology used to to generate

an animal that has the same nuclear DNA as another animal.Scientists transfer genetic material from the nucleus of a donor cell to an egg whose nucleus has been removed.The cloned embryo is transferred to the uterus of a female host and continues to develop until birth.

Risks of cloning

Compromised immune function Infections Tumor Cloned animals can die very young They can be abnormally large

Students’ activity

Write 5 sentences about clonation.

TEST

Answer to the following questions: 1) What type of cells are visible to naked eye? 2) Can you explain why the onion cells are not green? 3)What is absent in the plant cells? 4) What substitutes it? 5)What is the DNA? 6)Where can you put a piece of onion skin to examine it

with the microscope? 7)What animal was the first to be cloned? 8)Why should doctors harvest stem cells? 9)What are the dangers of clonation? 10)What other types of animals have been cloned?

A.S. 2006/07 - CLIL: test di Biologia Cognome ............................................. Nome ................................ Classe 2ª B Ling. Quali sono le ragioni per cui gli scienziati utilizzano il microscopio nella loro ricerca? Da che cosa è costituito un microscopio ottico composto? Che cos'è il potere di risoluzione di un microscopio? Se l'oculare di un microscopio composto dà un ingrandimento di 10x e l'obiettivo di

40x, qual è l'ingrandimento complessivo del microscopio? Un microscopio composto ha due obiettivi, uno di 10x e l'altro di 50x. a) Quale usereste per individuare un oggetto? b) Quale usereste per esaminare l'oggetto con maggiore

precisione. Scegli il complemento corretto: Al microscopio ottico composto, in una cellula eucariote, si possono vedere

distintamente: a) il nucleo, i vacuoli e i cloroplasti; b) la molecola del DNA e quella della clorofilla; c) i ribosomi e la membrana cellulare; d) il reticolo endoplasmatico liscio e quello ruvido. Scegli il complemento errato: In un microscopio ottico composto...

a) la messa a fuoco si ottiene utilizzando le viti macrometrica e micrometrica;

b) si possono osservare cellule vive; c) maggiore è l'ingrandimento, maggiore è il potere di risoluzione; d) si possono ottenere al massimo 1500 ingrandimenti.