1. Cells, tissues and organs
Human Biology ATAR Year 11
Chapter 3
Pages

2. Keywords Making connections
Cells Tissues Organs Cell membrane Cytoplasm Cytosol Organelles Nucleus Centrioles Endoplasmic reticulum Ribosomes Golgi bodies Lysosomes Mitochondria
Every cell in our bodies 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 our body functions.
Keywords
Making connections

3. Cells There is a hierarchy of structural organisation within the body
Cells tissues organs systems
Cells are the basic unit

4. Tissues & organs
Tissues are composed of cells with similar structure and function.
Example: cardiac muscle
Organs are structures of definite form and structure. The have a specific function within a system. Organs are usually composed of different types of tissues.
Example: heart as part of the circulatory system

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 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

7. 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.

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

11. Nucleus
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

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. 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
Endoplasmic
reticulum
Processing and transport centre
Rough (+ribosomes) or smooth (-ribosomes)
Golgi bodies
Packaging & export centre – vesicles
Lysosomes
Recycling & waste disposal centre
Mitochondria
Power supply centre
Nucleus
DNA – blueprint for building specifications
Ribosomes
Assembly line – manufacture of proteins

15. Internet links – student resources