This is a presentation designed to help explain the section of the Edexcel IGCSE Biology course about cell differentiation and organisation. For more help with IGCSE Biology please visit mrexham.com

1. IGCSE Biology – 4BI0
MAKING SENSE OF
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1.1 Life Processes – Differentiation and organisation
Objectives
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• Can you explain the organisation of an
organism using the following terms:
organelles, cells, tissues, organs and organ
systems?

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1.1 Life Processes – Differentiation and organisation
Cell division
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• Multicellular organisms begin life as a single
fertilised egg cell called a ZYGOTE.
• It then divides over and over again by MITOSIS

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1.1 Life Processes – Differentiation and organisation
Differentiation
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• As the developing embryo grows, cells
become specialised to carry out particular
roles.
• This is called differentiation and is controlled
by genes.
• As all cells have the same genes, some must
be switched on and some switched off for this
to work. This is discussed further in the IGCSE
course.

5. Copyright © 2015 Henry Exham
1.1 Life Processes – Differentiation and organisation
Specialised cells
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• Here are a few examples of specialised cells
that you will meet throughout the IGCSE
Biology course.
• They will be mentioned briefly here as they
will be explained fully in each relevant section.

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1.1 Life Processes – Differentiation and organisation
Specialised cells
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• Very long cell for carrying impulses around
the body along its axon.
• Insulated by a myelin sheath to make the
signal travel quicker.

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1.1 Life Processes – Differentiation and organisation
Specialised cells
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• Sperm cells have a tail for swimming.
• The head contains the genes from the father
in the nucleus.
• The acrosome digests its way into the egg for
fertilisation.

8. Copyright © 2015 Henry Exham
1.1 Life Processes – Differentiation and organisation
Specialised cells
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• This cell is found in the
leaves of plants.
• It is packed full of
chloroplasts for
photosynthesis.
• It is a regular shape in order
to pack many into the leaf.

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1.1 Life Processes – Differentiation and organisation
Specialised cells
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• This carries the water up the
stem of a plant.
• It is dead, hollow and
strengthened in order to do
this.

10. Copyright © 2015 Henry Exham
1.1 Life Processes – Differentiation and organisation
Cells tissues and organs
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• Each cell has many organelles inside it’s
cytoplasm to help it carry out its function.
• Cells with a similar function are grouped
together in TISSUES.
• A collection of similar tissues carrying out a
particular function is called an ORGAN.
• In animals, jobs are usually carried out by
several different organs working together. This
is called an ORGAN SYSTEM.

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1.1 Life Processes – Differentiation and organisation
Cells tissues and organs
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Organelles
Cells
Tissues
Organs
Organ Systems

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1.1 Life Processes – Differentiation and organisation
Cells tissues and organs
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Some of the key major human organs

13. Copyright © 2015 Henry Exham
1.1 Life Processes – Differentiation and organisation
Cells tissues and organs
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