Transcript National 4/5 Biology - Multicelluar Organisms

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Section 1 – Cells, tissues & organs
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1) Which of the labelled structures above
Indicates this is a plant cell?
2) What is the name of this structure?
3) Identify the structures labelled
above
4) Which of these would NOT be found
In an animal cell?
All of these are different
cells found in humans
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*Why are there so many
different types of cells?
*How do we get all these
different types of cell?
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* Today we will learn:
* - how cells are organised
* - examples of tissues and organs in the human
body
* - why many different cell types can arise from
an original cell
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Cells are the basic unit of life
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So, cells are arranged into tissues
- they can carry out all the functions needed for life
Many living organisms are composed of only one cell
- e.g. an amoeba
Most living organisms are made of many millions of cells
It would be inefficient if every cell performed exactly the same
function
- groups of cells specialised to form a particular function
Some of these are arranged into distinct structures – organs
- e.g. nerve cells form tissues which form the brain
How many other organs do you know?
Lungs
(Breathing
system)
Heart (Circulatory
system)
Liver
Stomach (Digestive
system)
Large intestine
Small intestine
SCN 3-12a
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* An organism with many different cells is
multicellular
* Cells will vary in size, shape, and structure
* - this allows these cells to perform different
functions
* - e.g. a liver cell and brain cell have very
different structures and functions
Liver Cell
Brain cell
* All cells in a particular organism start off
identical
* All of these will contain the same genes
* As they start to specialise, some genes
switch off, whilst others stay on
* The genes left on will carry information for
specific functions
* E.g. a nerve cell will have genes for
producing nerve fibres switched on
* http://www.twigonglow.com/films/differen
t-types-of-cell-1042/
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* 1) Genes control the activity of the cell. In
which part of a cell are they found?
* 2) Which substance do red blood cells transport
around the body?
* 3) Which organelle allows leaf cells to absorb
sunlight
* 4) What is the function of a root cell in a plant?