1. What are these cells?
How are they specialised to perform their function?

2. Cells
Living organisms can be made up of a single cell, e.g. bacteria, or they can be made up of many cells e.g. plants, animals or fungi. Unicellular organisms, like bacteria, are able to perform all life functions within one single cell. Multicellular organisms require a number of different cells to perform all life functions.

3. Which organism has the highest surface area to volume ratio?
The single celled amoeba.
Polar bear or other multicellular organism.

4. Which organism has the highest surface area to volume ratio?
The single celled amoeba
12:8 = 3:2
Polar bear or other multi cellular organism
20:25

5. All cells exposed to environment. Effective exchange surface.
Single celled organisms
Multicellular organisms
Large s/a:volume.
All cells exposed to environment.
Effective exchange surface.
All cells perform all functions.
Smaller s/a:volume.
Not all cells in contact with external environment.
Therefore: specialised cells to perform different functions.

6. Specialised Cells What do you think a specialised cell can do?
Eukaryotic organisms (e.g. humans and plants) are not usually made of generalised cells.
We have developed specialised cells that have adaptations to allow them to complete specific functions.

7. Specialised Cells
Certain cells in the human body are specialised so that they can carry out particular jobs.
This allows the body to function more efficiently.
What types of specialised cells are there in the body?

8. Specialised Cells – examples
Fat cells Root hair cells Palisade mesophyll (leaf) cells Sperm cells Red blood cells Nerve cells Phloem cells Muscle cells

9. How do cells become specialised?
As organisms develop, cells differentiate to form different specialised cells. This differentiation is usually at an early stage of development. While it is differentiating, the cell produces different organelles that allow it to do a certain function. Remember, some specialised cells will work on their own, while others will work as a part of a tissue, organ or even a whole organism.

10. Cell Differentiation – summary
As an organism develops, cells differentiate to form different types of cells. 1 Most types of animal cell differentiate at an early stage. 2 Many types of plant cells retain the ability to differentiate throughout life. In mature animals, cell division is mainly restricted to repair and replacement. As a cell differentiates, it acquires different organelles to enable it to carry out a certain function.

11. Can you define the key words?
Unicellular Specialised cell Cell differentiation
Made up of one cell
A cell that has gone through cell differentiation and become a cell that has a special function
The process by which cells become specialised to do their different functions

12. What is differentiation?
Young cell
Cell division
Cell growth
Cell specialisation
Mature cell
-Unlikely to divide again
What is differentiation?
When a cell becomes specialised to carry out a particular function.
What categories of differentiation are there?
Change number of particular organelle e.g. muscle cell.
Change the shape of the cell e.g. root hair cell.
Change some of the contents of the cell e.g. RBC.
ALL 3!

13. How the cell is specialised for its function Erythrocyte Neutrophil
Specialised Cells
Specialised Cell
How the cell is specialised for its function
Erythrocyte
Neutrophil
Sperm cell
Palisade cell
Root hair cell
Guard cell
Ciliated epithelial cell

14. Describe the cell's shape and how it helps it do it job.

15. Describe the cell's shape and how it helps it do it job.
Ciliated epithelium cell - has hairs (cilia) which 'waft' to trap dirt and germs

16. Describe the cell's shape and how it helps it do it job.

17. Describe the cell's shape and how it helps it do it job.

18. Describe the cell's shape and how it helps it do it job.

19. Describe the cell's shape and how it helps it do it job.

20. Describe the cell's shape and how it helps it do it job.

21. Describe the cell's shape and how it helps it do it job.

22. Describe the cell's shape and how it helps it do it job.
Red blood cell - disc shaped to carry oxygen around the body.

23. Describe the cell's shape and how it helps it do it job.
Palisade leaf cell- filled with green chloroplasts to get energy from sunlight.

24. Describe the cell's shape and how it helps it do it job.
Nerve cell - long, thin and 'wire-like' to send messages around the body.

25. Describe the cell's shape and how it helps it do it job.
Root hair cell - hair-like projections to absorb water.

26. Describe the cell's shape and how it helps it do it job.
Sperm cell - tail to help it swim to the egg cell.

27. Describe the cell's shape and how it helps it do it job.
Egg cell - large contains a lot of food for the baby to grow.