Transcript THE CELL
Docenti: Aniello Terracciano
Maria Rosaria Barbarito
Classe : 2 b Linguistico
Anno sc.: 2006/07
Human red blood cells
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’
Leggere e comprendere testi scientifici/ to read and to understand scientific
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?
MATCH THE ENGLISH WORDS WITH THE ITALIAN ONES
DNA double helix
a. Respirazione cellulare
e. Molecola nutriente
h. Doppia elica del DNA
Fase di trascrizione
k. Codice genetico
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.
A single-celled bacteria
of the type: E. coli
The one-celled organism
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
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
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.
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 ………….
Small cells (>5mm)
Larger cells (>10mm)
No nucleus or any membrane bound Always have nucleus and membrane
DNA is circular ,without proteins
DNA is linear and associated with
protein to form chromatin
Ribosomes are small(70s)
Ribosomes are large (80s)
Cell division is by binary fission
Cell division is by mitosis or meiosis
Reproduction is always asexual
Reproduction is sexual or asexual
Prokaryotic cells are larger
Eukaryotic cells are unicellular
Prokaryotic cells have no cytoskeleton
Eukaryotic cells have a linear DNA
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
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
Have you ever seen a cell?
What do you remember about it?
The microscope is a crucial magnifying tool for
examining cells, their processes, and their
interactions with the environment.
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 lenses
Arm: Supports the tube and connects it to the base
Base: The bottom of the microscope, used for support
Illuminator: A steady light source
Stage: 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
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
Tools & Materials
- 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
h. Describe in a few sentences what you saw while looking
at the cell through the microscope.
Now compare and contrast what you have observed. The following vocabulary should be
discussed and or defined:
Plants have thick cell walls to strengthen
the plant stem.
Cell Membranes Animals have thin membranes because they
have other forms of skeletons.
Green colored structures that produce food.
Both plants and animals have these; they
control heredity and cell division.
A clear liquid where most of the cells life
(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.
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
A DNA fragment is transferred from one
organism to a self-replicating genetic
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.
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
Risks of cloning
Compromised immune function
Cloned animals can die very young
They can be abnormally large
Write 5 sentences about clonation.
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
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.