Download Cells

Cells
“We know more about other
planets than we do about our
own”
Characteristics of life poster
 Create a poster highlighting the characteristics of
living things (MRS GREN). Your poster should be made
on computer and should contain:
 a description of each element of MRS GREN
 An image representing each element of MRS GREN.
This can be symbolic or literal
You can use the student checklist for B1 to
check your definitions
Where in the world?
Think about a city. What are some of the important requirements a city
must have to keeps its inhabitants alive and happy
From your list remove all the non essential
items (e.g. cinemas, malls), things that are
only there for entertainment
What you should have left are only
the things that maintain the function
of the city.
How does a
cell
compare to
a city?
What is a cell?
A cell is the basic unit of life, from which larger structures
such as tissue and organs are made.
 Unicellular organisms,
such as bacteria, consist of
just a single cell.
 Multicellular organisms
consists of many cells –
humans are made from an
estimated 50 trillion cells!
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How big is a cell?
Most plant and animal cells are between 0.025 µm and
60 µm in size – around half the diameter of a human hair
– and too small to see without a microscope.
The largest cell in the human
body is the female egg cell,
(ovum) at around 1,000 µm
in diameter.
The smallest human cell is
the sperm cell – the head is
around 5 µm long.
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© Boardworks Ltd 2007
Specialized cells
Most plants and animals are multicellular. The human
body is made up of around 200 different types of cell, all
working together.
Most cells are specialized, meaning
that each type of cell has a specific
structure and function.
All cells with a nucleus contain the
same genes, but different cells
activate different genes so they only
produce the proteins they need.
However, all cells have certain
common features and structures
called organelles.
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 All known living organisms are made of cells.
 Levels of organization exist in multicellular
organisms.
 Tissues are a group of cells that all perform
the same function.
What do cells contain?
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Animal or plant?
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Intro to Microscopes
• Parts of a microscope and safe handling
procedures.
Calculating Magnification
• Size in the picture = Actual size (real life) X
magnification
=
X
•
2000 mm
=
20mm
x 100x
• This equation can be re-arranged to solve for any of the
components.