Cell form and function
Rosalie Crawford - Veronica Revel
biologyCourmayeur
FondazioneCLIL
Liceo Linguistico
The cell theory
1
• Every organism is made of cells and every cell comes from
another cell.
• A cell is the basic unit of form and function.
• Every organism is made of one or more cells, and each cell
carries on functions so that the organism can live.
• The form and structure of a cell provide protection and
support, forming a protective barrier between the cell and its
environment, transporting materials, building and repairing,
storing and releasing energy and waste materials and
reproducing.
1- The main source for this presentation is Cecie Starr, Biology: Progetto
Bioenglish, LifeSciences, Garzanti Scuola, 2009.
Specialized cell
• Smallest unit that can live
and reproduce on its own
or as part of a muticelled
organism.
• A cell has DNA, an
outermost membrane and
other components.
Tissue
• Organized array of cells
and substances that are
interacting in some task.
• Bone tissue consists of
secretions from cells such
as this one.
Organ
• Structural unit of two or
more tissues that interact
in one or more tasks.
• This parrotfish eye is a
sensory organ used in
vision.
Organ system
• Organs that interact in
one or more tasks.
• The skin of this
parrotfish is an organ
system with tissue layers,
organs such as glands and
other parts.
The cell wall
• The cell wall is made of cellulose, which is a
non-living material.
• It is made up of a chain of sugar molecules.
• This stiff, rigid wall is found only in plant
cells, not in animal cells.
• This wall allows certain gases and water to
enter ths cell.
The cell membrane
• Inside a plant cell, it’s inside the cell wall.
• In an animal cell, it forms an outer covering
for the cell.
• It maintains the correct chemical environment
within the cell.
• The functions of the membrane are to help
control movement of materials in and out of
the cell and to change its shape under
pressure.
The nucleus
• The nucleus controls the cell activities
(growth, development and reproduction).
• It could be said it is the brain of the cell that
regulates and controls the various cell
activities.
• The nucleus is surrounded by a membrane as
well.
• This nuclear membrane lets materials pass
into and out of the nucleus.
• Pores (small openings) act as entryways.
Chromosomes
• Chromosomes are rod-shaped and delicate.
• They are located in the nucleus and direct all the activities of the
cell, including reproduction and growth.
• Chromosones are large and complex molecules that are compounds
referred to as nucleic acids, which store information that help the
cell make its necessary proteins.
• Some proteins are made up of different enzymes and hormones.
These substances regulate many cell activities.
• The two nucleic acids found in cells are DNA (deoxyribonucleic
acid) and RNA (ribonucleic acid)
• The DNA stays in the nucleus and the RNA carries its information
(mostly protein building) outside the nucleus through the pores.
• It is important to know that chromosomes and nucleolus are
located in the nucleus.
• The nucleolus is responsible for the production of ribosomes.
The endoplasmic reticulum
• These are passageways that make up the transportation
system of the cell. They are important cell organelles that
carry proteins and are located in the cytoplasm, the material
inside a cell between the cell’s nucleus and the cell membrane.
• On the inner surface of the endoplasmic reticulum the
ribosomes are attached. Produced in the nucleolus, they leave
the nucleolus via the nucleus.
• Ribosomes are made up of the nucleic acid RNA and they are
an important protein producing place.
• The RNA directs the production of proteins.
• NB the production of RNA is controlled by the DNA in the
chomosomes, and the DNA is the main control centre of the
cell.
Mitochondria
• Mitochondria supply energy to the cell.
• They are larger than the ribosomes, are rod-shaped, and are
said to be the “powerhouses” of the cell.
• This is where energy is released from food in the process
known as respiration.
• Plant cells and some animal cells have
vacuoles, which are water-filled, round and sac-like
structures that float in the cytoplasm and act as storage
tanks that hold food and other materials.
• In healthy plants they are large and help support the cell.
Lysosomes
• Lysosomes are structures involved with the
digestive processes of the cell.
• They contain enzymes that break down food
molecules into smaller ones. When the
lysosomes have done their work, food
molecules are then transported to the
mitochondria where they are used to make
energy for the cell.
Chloroplasts
• Chloroplasts are structures that contain the
green pigment chlorophyll which absorbs the
light energy that plants need to make food.
This process is called photosynthesis.
• Chloroplasts and chlorophyll only exist in
plant cells.
Animal cell diagram
Plant cell diagram
Language focus
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Although – sebbene
As a result of – di conseguenza
Because of – a causa di
Despite – nonostante
Even though – anche se
First of all – innanzitutto
For instance – per esempio
However – sebbene
In addition – inoltre
In order to – in modo da
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In spite of – invece di
Instead – invece
Once – una volta
On the other hand – d’altra parte
Moreover – inoltre
So that – cossichè
Thanks to – grazie a
Therefore – pertanto
Unless –a meno che
Until – fino a che
Whereas/ while - mentre
Glossary
• The cell membrane keeps all the components
of the cell close together and controls
chemicals in and out of the cell.
• The cell wall gives strength and support to the
cell.
• A chromosome is a structure in the nucleus
composed of DNA and proteins.
• Endoplasmic reticulum is found in cytoplasm
and is a system of tubules or vesicles.
• Mitochondria is where respiration takes place.
Glossary continued
• The nucleolus is part of the cell nucleus
producing ribosomes.
• The nucleus controls all chemical reactions
and it carries all the information of the cell.
• An organ is tissue working together.
• An organism is the smallest unit that can live
and reproduce of its own.
• A ribosome is a particle in the cell which
assembles proteins .
• Tissue is a group of specialized cells.
CELL SPECIALIZATION
• So far, we have spoken
about “typical” cells.
• Different cells are
specialized to function at a
variety of jobs.
• An example of a
specialized cell is the
sperm cell, whose job is to
swim to the egg and
fertilize it.
The sperm cell
• It has a tail to enable it to swim;
• It has many mitochondria to
provide energy for this
swimming;
• The acrosome contains
digestive enzymes that make an
opening in the egg cell
membrane to allow entry;
• The nucleus contains
chromosomes which carry the
genetic material that will be
transmitted to the offspring.
CELL ORGANIZATION
• There is a division of labour within a
multicellular organism, which is an
expression meaning that the work of keeping
the organism alive is divided among the
different parts of the body. The arrangement
of specialized parts within an organism is
often referred to as levels of organization.
ORGAN SYSTEMS AND FUNCTIONS
• THE INTEGUMENTARY SYSTEM: protects body from
injury, dehydration and some pathogens; controls its
temperature; excretes certain wastes; receives some external
stimuli.
• THE NERVOUS SYSTEM: detects external and internal
stimuli; controls and coordinates the responses to stimuli;
integrates all organ system activities.
• THE MUSCULAR SYSTEM: moves body and its internal
parts; maintains posture; generates heat by increases in
metabolic activity.
ORGAN SYSTEMS AND FUNCTIONS
• THE SKELETAR SYSTEM: supports and protects body
parts; provides muscle attachment sites; produces red blood
cells; stores calcium, phosphorus.
• THE CIRCULATORY SYSTEM: rapidly transports many
materials to and from interstitial fluid and cells; helps
stabilize internal PH and temperature.
• THE ENDOCRINE SYSTEM: hormonally controls body
functioning; with nervous system integrates short- and longterm activities.
• THE LYMPHATIC SYSTEM: collects and returns some
tissue fluid to the bloodstream; defends the body against
infection and tissue damage.
ORGAN SYSTEMS AND FUNCTIONS
• THE RESPIRATORY SYSTEM: rapidly delivers oxygen to the tissue
fluid thus bathes all living cells; removes carbon dioxide wastes of cells;
helps regulate pH.
• THE DIGESTIVE SYSTEM: ingests food and water, chemically breaks
down food and absorbs small mollecules into internal environment;
eliminates food residues.
• THE URINARY SYSTEM: maintains the volume and compostion of
internal environment; excretes excess fluid and bloodborne wastes.
• THE REPRODUCTIVE SYSTEM: female: produces eggs; after
fertilization, ensures a protected, nutritive environment for the
development of new individuals; male: produces and transfers sperm to
the female; hormones of both systems also influence other organ systems.
Without great minds, these
discoveries would never have
happened
• The existence of
organelles was not known
until the 17th century,
when the microscope was
invented by a Dutchman,
Anton von Leeuwenhoek
(1632-1723).
The first man to see cells….
• An English scientist, Robert Hooke (1635 -1703), using a
very simple microscope, saw dead plant cells on a thin
piece of cork.