1. Cells: structure & function
Biology ATAR Unit 2
Text: Chapter 7
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2. Endoplasmic reticulum Golgi body (apparatus) Lysosome Mitochondria
Keywords
Making connections
Organelles
Cell membrane
Cell wall
Chloroplast
Endoplasmic reticulum
Golgi body (apparatus)
Lysosome
Mitochondria
Nucleus
Plastid
Ribosome
Vacuole
Every cell in an organism is connected in some way to every other cell.
Cells make up tissues, tissues make up organs and organs work together as systems.
Cells are the basic unit of life. They are extremely complex machines with many interdependent parts.
Understanding how a cell works is the first step to understanding how organisms function.

3. Learning outcomes
Describe and explain the function of the different organelles
Relate the structure of organelles to their function
Describe and understand the difference between plant and animal cells

4. Cell theory Cells are the smallest living units of organisms
All cells come from pre-existing cells.
Each organism is made of one or more cells.

5. Cell structure Cells are made up of the following parts:
Cell membrane the skin
Cytosol the fluid
Organelles the machines
Cytoskeleton the bones
Cytoplasm = cytosol + organelles

6. Cell structure
Organelles are the internal structure of cells. Cells from all sorts of organisms have at least some, if not all, of these structures.
Cell membrane
Endoplasmic reticulum
Golgi bodies (apparatus)
Mitochondria
Nucleus
Ribosomes
ANIMAL CELLS
Centrioles
Lysosomes
PLANT CELLS
Cell wall
Chloroplasts
Vacuoles

7. Cell membrane Structure
Is a bilayer of phospholipids molecules enclosing the cytoplasm in all cells
Function
It controls the movement of substances into and out of the cell
It contains receptor proteins that allow it to communicate with other cells

8. Endoplasmic reticulum
Structure
A network of intracellular membranes that links with the plasma membrane and other membranous organelles.
Endoplasmic reticulum may be rough (associated with ribosomes) or smooth (lacking ribosomes).
Function
It is involved with the production, processing, transport and storage of materials within the cell.

9. Golgi bodies (golgi apparatus)
Structure
A stack of flat membrane sacs linked to the endoplasmic reticulum.
Function
The golgi bodies package proteins into membrane- bound vesicles before they are secreted from the cell.

10. ANIMAL CELLS: Lysosomes
Structure
Membrane-bound vesicles containing powerful enzymes
Function
The enzymes break down debris and foreign material

11. Structure
The nucleus is a large organelle that is surrounded by a porous membrane.
The nucleus contains genetic material (DNA)
Function
The nucleus controls all cellular activity
Nucleus

12. Mitochondria Structure
Mitochondria are composed of many folded layers of membrane
Function
The mitochondria are involved in energy production

13. Ribosomes
Structure
Tiny organelles located in the cytosol, sometimes associated with endoplasmic reticulum.
Function
They are sites of production of proteins.

14. ANIMAL CELLS: Centrioles
Structure
A pair of small cylindrical structures composed of microtubules.
Function
They are involved in the separation of chromosomes during cell division in animal cells and protists. They are not found in plant cells.

15. PLANT CELLS: Cell wall Structure The cell wall is found in plant cells
It is made of cellulose and surrounds the cell membrane
Lignin is present in the cell wall of the xylem of woody plants to give them further support
Function
provides support
prevents expansion of the cell
allows water and dissolved substances to pass freely through it

16. PLANT CELLS: Chloroplasts
Structure
Found mostly in plant leaf cells
Contains chlorophyll – a green pigment that absorbs light energy
Function
photosynthesis

17. PLANT CELLS: Vacuole Structure A vacuole is found in most plant cells
They may contain food, enzymes and waste products
Function
Vacuoles are filled with fluid and provide physical support

18. SUMMARY: Cell structures
Function
Cell membrane
Border patrol: controls movement of substances in and out of the cell
Enables chemical communication between cells
Centrioles
Separate chromosomes during cell division (protista and animalia only)
Endoplasmic
reticulum
Processing and transport centre
Rough (+ribosomes) or smooth (-ribosomes)
Golgi bodies
Packaging & export centre – vesicles
Lysosomes
Recycling & waste disposal centre (animalia only)
Mitochondria
Power supply centre

19. SUMMARY: Cell structures
Function
Nucleus
DNA – blueprint for building specifications
Ribosomes
Assembly line – manufacture of proteins
Vacuoles
Storage centre – food or enzymes
Support – fluid (plantae)
Contractile vacuole
Osmoregulation (maintaining fluid balance)
Protists and unicellular algae
PLANT CELLS ALSO CONTAIN:
Cell wall
Structure and support
Chloroplasts
Food manufacturing centre - photosynthesis
Plastids
Class of organelles which include:
Amyloplasts (starch storage)
Chromoplasts (pigmentation organelles)

20. Contractile vacuole