All living organisms are made up of cells. Find how cells work and their structure.

1. THE CELL STRUCTURE AND CELL
ORGANISATION
BY MR. NATHAN SSEKAMATTE

2. Learning Objective
• To draw and label the different parts of an animal and plant cell
• To explain the functions of a the different parts of a cell
• To give the similarities and differences between the plant and animal
cell.

3. THE CELL STRUCTURES
• All living things are made up of cells
• A cell is the smallest unit of life that carries out all life processes.
• We have 2 kinds of cells that is to say the animal cell found in animals
and the plant cell found in plants
• In both the animal and plants the cell combine to form tissues, the
tissues combine to form organs and the organs also combine to form
system which make up the body.
• Cells tissues organs system

4. THE STRUCTURE OF THE ANIMAL CELL

5. THE STRUCTURE OF A PLANT CELL

6. FUNCTIONS OF DIFFERENT PARTS OF CELLS.
CELL WALL
• it binds the protoplasm and allows exchange of materials between
the cell and its environment
• NB The cell wall is found only in pant cell
• The cell wall is made up of cellulose which is rigid and therefore gives
a plant its definite shape

7. CELL MEMBRANE/ PLASMA MEMBRANE
The cell membrane is a semipermeable lipid bilayer that surrounds the
cytoplasm of all cells. In animal cells, it is the outermost layer of the
cell. In plants, fungi and some bacteria, a cell wall surrounds the cell
membrane to form the cell's outermost layer
1. The cell membrane separates the interior of all cells from the
outside environment which protects the cell from its environment
2. It controls the exchange of materials between the cell and the
environment

8. CYTOPLASM
This is where all the activities of the cell take place
It contains the cell organelles which are outside the nucleus
NUCLEUS
This located in the center of the cytoplasm in animal cell and at the
sides for the plant cell.
It contains the genetic material. This material is organized as DNA
molecules, along with a variety of proteins, to form chromosomes
It controls cell division

9. NUCLEAR MEMBRANE
• It binds the nucleus therefore it separates the nuclear material from
the cytoplasm
• It allows exchange of material between the nucleus and the
cytoplasm
CELL VACUOLE
It contains a fluid called cell sap which acts as a temporary food store
It stores waste products from the cell

10. CHLOROPLAST
They are found only in the plant cell.
They contain a structure called chlorophyll therefore they are sites for
photosynthesis

11. MITOCHONDRIA
This is where respiration takes place which leads to production of
energy. This is a site for aerobic respiration

12. ENDOPLASMIC RETICULUM
There are two types of ER: rough endoplasmic reticulum (RER) and
smooth endoplasmic reticulum (SER). The outer face of the rough
endoplasmic reticulum has ribosomes that are the sites of Protein
synthesis. The smooth endoplasmic reticulum lacks ribosomes and
functions in lipid synthesis

13. .

14. • NB. 1. All cells have the mitochondria and rough endoplasmic
reticulum except prokaryotic cells
2. Ribosome is a site of biological protein synthesis

15. SIMILARITIES OF THE PLANT AND ANIMAL CELL.
• They both contain a nucleus
• They both have a cytoplasm
• They both have a mitochondria
• They both undergo cell division

16. DIFFERENCES

17. .

18. Microscopic view of animal and plant cells.

19. CATEGORIES OF CELLS

20. RED BLOOD CELLS
Red blood cells in blood
These transport oxygen in our bodies

21. WHITE BLOOD CELLS
This defends the body against infections and diseases

22. .

23. PLATELETS
These are used for blood clotting.

24. NERVE CELL
These help in the transmission of impulses

27. ROOT HAIR CELLS
They are found in plant roots
They absorb water and mineral salts from the soil

28. XYLEM VESSELS
These transport water to different parts of the plant

29. PHLOEM
This transports dissolved food to different parts of the plant.

30. PALLISADE MESOPHYLL CELLS
These are found in leaves of green plants
They carry out the process of photosynthesis

31. .

32. .

33. .

34. .

35. Levels of organisation

36. Learning Objective
By the end of the lesson, I should be able to;
• Describe the meaning of the terms: cell, tissue,organ, organ system
and organism

37. TISSUE
• This is a group of cells with similar structures working together to perform a
shared function.
•A tissue may be made up of single type of cell or may comprise of different
types of cells. E.g.
i) Blood tissue made up of red blood cells, white blood cells and platelets. Blood
transports materials in the body and offers protection.
ii) Nervous tissue made up of nerve cells. It transmits impulses in the body.
iii) Muscular tissue made up of muscle cells which cause movement of body parts
iv) Photosynthetic tissue made of palisade cells for photosynthesis.

38. .

39. ORGAN
This is a structure made up of a group of tissues, working together to perform
specific functions.
• e.g. i) eye for sight ii) Heart for pumping blood iii) Ear for hearing
iv) Kidney for purifying blood v) Leaves for photosynthesis
vi) Roots for absorbing water and mineral salts

40. .

42. ORGAN SYSTEM
This is a group of organs with related functions, working together to perform body
functions.
•e.g.
•i) nervous system (Brain, Spinal cord),
•ii) circulatory system (Heart, Lungs and Blood vessels),
•iii) Digestive system (gullet, stomach, small intestines).
•iv) Shoot system (leaves stems. flowers)
•v) Root system (roots)

43. .

44. .

45. .

46. .