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Introduction
Every
individual living thing is made of smaller parts. The smaller
parts have different functions, but all of the parts work
together to enable the individual to live and survive in
its environment. The smaller parts are made of even smaller
parts, which are made of smaller parts, and smaller parts,
until you reach the smallest part of all: the cell. The
cell is the basic building block of all living things.
Characteristics of Life
The
7 life processes are what all living organisms do. You must
learn these for the exam. A good way of doing this is remembering
the phrase "Mrs Gren"
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M
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Movement
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Animals
move to find food and away from predators. Plants
move towards light. |
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R
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Reproduction
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Both
animals and plants reproduce to make their species
carry on. |
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S
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Sensitivity
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Animals
and plants are sensitive to light. |
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G
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Growth
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Animals
grow larger and stronger which helps them hunt better.
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R
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Respiration
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Animals
and plants must turn their food into energy.
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E
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Excretion
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Waste
products must be excreted from plants and animals.
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N
|
Nutrition
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Animals
need food for respiration and plants need minerals
from the soil. |
Cells
| Protoplasm |
Consists
of cytoplasm and nucleus. |
| Cytoplasm |
Jelly
like substance where chemical reactions take place and
other parts are embedded. |
| Nucleus |
Controls
reproduction and also contains the characteristics of
the cell. |
| Cell
membrane |
Surrounds
the cell and controls what moves in and out of the cell. |
| Mitochondria
|
Found
only in plant cells where respiration occurs. |
| Chloroplasts
|
These
makes plants green. They contain chlorophyll which is
needed for photosynthesis. |
| Cell
wall |
Gives
the cell its shape. The cell's "skeleton". |
| Vacuoles |
Where
the cell sap is stored. |
Plant and Animal Cells
Typical
plant cell
Typical
animal cell
| Plant
cell |
Animal
cell |
| Fixed
structure. |
Can
change shape.
|
| Has a
cellulosecell wall and a cell membrane |
No
Cellulose cell wall |
| Chlorophyll
in chloroplasts |
No
Chlorophyll or chloroplasts |
| Large
vacuoles |
Small
or no vacuoles
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Tissues, Organs and Organ Systems
Some
tiny organisms, called protists, are made of only one cell.
Since the single cell must work alone, it has to do everything
to make sure that the organism survives. Protists can not
be seen with the human eye. To observe tiny organisms in
their microworlds, you can use a microscope.
Multi-celled
organisms are more complex. Different parts have different
functions, each part sharing the work and cooperating to
make sure that the organism survives.
In a
plant, for example, the cells working together in the roots
make sure that the plant gets the water and nutrients from
the soil that the plant needs to survive. The cells working
together in the leaves make sure that the plant exchanges
oxygen for the carbon dioxide that the plant needs to survive.
The roots and the leaves work together as a system for the
plant to survive.
The
parts of an animal also work together to make sure that
the animal is able to survive in its environment. An animal's
anatomy must be adapted for its survival.
Tissues
- Made up of lots of cells of the same type. (e.g. muscle
tissue is made up of many muscle cells)
Organs
- Different tissues working together to carry out a certain
function. An organ can contain different types of tissue
(e.g. the heart).
Organ
Systems - Organ systems are composed of two or more
different organs that work together to provide a common
function.
Observing Cells
How
can you find out more about the cell organelles and the
jobs they do? The microscope allows scientists to examine
cells in detail. Either an electron microscope or a light
microscope may be used.
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