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Georgia Lofts

Georgia Lofts

Email: georgialofts@gmail.com

Total Article : 115

About Me:I am a second year student studying BioMedical Science. I am interested in a wide range of topics but particularly like to focus on Biology, Art and Philosophy.

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GCSE Revision: Cell Specialisation

GCSE Revision: Cell Specialisation

GCSE BIOLOGY REVISION: CELL SPECIALISATION

 

Students should be able to, when provided with appropriate information, explain how the structure of different types of cell relate to their function in a tissue, an organ or organ system, or the whole organism.

Cells may be specialised to carry out a particular function:

 • sperm cells, nerve cells and muscle cells in animals

 • root hair cells, xylem and phloem cells in plants.

 

Definitions:

 

Specialisation- the process by which cells develop into specific cells that are meant to carry out the correct function.

 

Tissue- a group of cells which work together to perform a particular function, for example epithelial tissue in animals and mesophyll tissue in plants.

 

Organ- a group of tissues which work together to perform a specific function. The lungs are an example of an organ in animals, and the stem is a plant example.

 

Organ system- a group of organs working together to perform a particular function for example the circulatory system and the respiratory system.

 

Often examiners will ask a rather vague question about being able to describe a specialised cell, explaining how it is well adapted. Sperm cells and root hair cells are the perfect examples to use when answering these types of questions. The question might be more specific, as the specification clearly states which cells to learn, you must learn all of them! Additionally, they could ask for two examples, in this case it is your choice which two specialised cells you talk about. But there are plenty of other specialised cells you could choose to learn about if you are interested. However, learning unique examples will not give you any extra marks.

 

Sperm cells

 

The acrosome (the head) contains digestive enzymes which penetrate through the egg

The middle piece is filled with lots of mitochondria for energy release to help propel the cell towards the egg

The tail allows the cell to swim efficiently

 

 

Nerve cells

 

Nerve cells extend to reach various parts of the body so that communications can be sent to and from the central nervous system

Extra branches allow further extension and so that the cell can communicate with other nerve cells, muscles and glands

Covered in a fatty myelin sheath which provides insulation, this speeds up the rate of action potentials. The name for this is called salutatory conduction.

 

Muscle cells

 

Contain protein filaments that slide over one another to cause contraction

Contain many mitochondria to provide energy for contraction

Skeletal muscle merges for contractions to be in unison

 

Root hair cells

 

Found in the root of plants

They have the role of absorbing water and minerals found in the soil

They have a large surface area (hair-like projections) allowing easier and efficient uptake

Each root hair cell contains a large number of mitochondria, this provides more energy for active transport.

 

Xylem

 

Absence of end walls to allow easy flow of water

Walls are thick and contain a woody substance called lignin to provide support and prevent collapse

 

 

Phloem

 

Assimilates can be transported up and down the stem

Has a companion cell to provide energy for transport

 

image-http://kmbiology.weebly.com/cell-specialization---notes.html

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